FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to cosmetics, more particularly, but not exclusively, to compositions and treatments useful in straightening hair.

Having a full, healthy and manageable head of hair is a common concern of men and women. Other than the number of hair fibers on a person's head, a full head of natural, healthy, manageable hair depends on the diameter and cross sectional area of the hair fibers, as well as various mechanical properties thereof. Hair fibers (about 50-100 μιη in diameter) are not continuous in their entire length, but rather the result of the combination of compact groups of cells within the follicle, from which originate three distinct layers: the cuticle, the cortex, and the medulla.

The cuticle is the outermost layer of a hair fiber which consists of flattened cells arranged in an overlapping fashion, from about 6 to 12 cells thick. The outermost layer of the cuticle is coated with a lipid substance that renders the outer surface of the hair hydrophobic. The overlapping cellular arrangement and the lipid coating confer barrier properties to the fiber and permit the cells to slide past each other as the fiber swells from within.

The cortex, immediately beneath the cuticle, consists of tightly packed, rod-like structures composed of melanin granules that pigment the shaft. The cortex accounts for about 80 % of the hair mass of the hair fiber, and provides most of the mechanical strength of a hair fiber. Much of this strength is due to the crosslinking of cysteine residues in covalent disulfide bonds; but much of hair fiber strength, as well as other properties, are also due to an extensive network of hydrogen bonding.

The innermost layer of a hair fiber, the medulla, is a core of loosely packed, cube-like cells with small packets of air between them. The width of each layer, as well as that of the entire shaft, can vary significantly even along the same hair. In some shafts, the medulla may be discontinuous or entirely absent.

The hair appearance depends considerably on the health of the cuticle. When the cuticle is strong and healthy, hair appears to be strong and healthy. Intact and closed cuticle acts as a protective shield against harmful environmental elements; when cuticle scales are open (raised), substances can be deposited in their structure. Physical-chemical manipulation of the scales of the cuticle causes the appearance of hair to be changed, creating all kinds of different effects which can vary in softness, color and even texture. Thus, from a cosmetic point of view, the cuticle is a very important component of the hair fiber [Rieger, M.M., ed. Harry's Cosmetology. 8 ^th ed., Chemical Publishing Co Inc., New York (2000)] . The cortex also has considerable cosmetic importance, as its optical properties strongly affect the color and shine of hair fiber [Kharin et al., J Biomed Optics 2009, 14: 1-7].

Hair types may be categorized into three large groups - African, Caucasian and Asian - which facilitates recognition of specific characteristics of each type of hair including color, curling and other parameters [Wolfram, J Am Acad Dermatol 2003, 48:S 106-S 114]. The amino acid composition of hair fibers is always the same and the ranges of their concentration overlap and do not appear to vary greatly with ethnicity. Moreover, apart from their ethnicity, all hair fibers have a high content of cysteine disulfide bonds, which contribute significantly to the stability of the fiber.

The natural shape and structural integrity of human hair depends, in part, on the orientation of disulfide bonds (cysteine-cysteine bonds) of keratin protein. In human hair, disulfide bonds contribute to tertiary and quaternary protein structure. It is generally thought that alteration of the disulfide bonds is necessary and/or useful to effect long term changes in the shape of hair.

Hair shaping treatments that do not rearrange the disulfide bonds result in changes in hair shape that last a relatively short time [Miranda- Vilela et al., Int J Cosmet Sci 2014, 36:2-11]. For example, the use of hairstyling products or physicochemical techniques such as dryer, flat iron and hot comb to style hair may create temporary straightening of the hair. However, the styled hair will return to its natural shape after a short time, as a result of exposure to moisture in the air or washing. The use of heat and moisture to straighten hair may break and reconfigure hydrogen bonds in the hair, but the disulfide bonds are not substantially affected. It is commonly believed that hydrogen bonds, by themselves, are insufficient to hold the shape of hair for a significant time, because the stronger disulfide bonds eventually force the hair to reassume its original shape.

Thus, a permanent straightening of the hair is commonly considered to involve the cleaving and reforming of a substantial number of disulfide bonds. Various chemical treatments for doing this are known in the literature. Depending on the straightening agent used, damage to the protein structure may be controlled to a more or less degree. That is, various types of protein structures of the treated hair may be broken down, or only a particular type of protein structure. For example, hair straightening products that alter primary structure do so by weakening and/or breaking the internal chemical bonds of hair protein amino acids. Regardless of where the protein structure is altered, effective straightening treatments cause natural curls to loosen and straighten. While some straightening agents may be more effective and/or efficient than others, the tradeoff is usually in the damage done to the hair and scalp, and the need for adjunct treatments to limit that damage. On the other hand, treatments which may be somewhat less damaging to the hair and scalp, may require a longer time to operate, or the application of significantly more product, or multiple applications to achieve a desired result.

Alkaline agents can stabilize straightened hair by altering primary structure, converting cysteine dimers to lanthionine, a monosulfide (thioether) analog of a cysteine disulfide dimer, in a process referred to as lanthionization [Bouillon & Wilkinson, J. The Science of Hair Care, 2nd edn. Taylor & Francis Group, New York, 2005; Wong et al., J Soc Cosmet Chem 1994, 45:347- 352]. However, lanthionization weakens hair fibers and it is well known that repeated use of alkaline hair straightening products can damage hair considerably.

Sulfur-containing agents, such as ammonium thioglycolate, ammonium sulfite, ammonium bisulfite, sodium metabisulfite (Na ₂ S205) and cysteine, act via milder mechanism, by reducing disulfide bonds (-S-S-) to thiosulfate groups (-S-SO ₃ ), also known as a Bunte salts. It has been reported that the formation of Bunte salts in hair treatment can be slowly reversed with water rinsing, to rebuild the disulfide bonds, or an oxidizing agent may be used to help form new disulfide bonds. Following reduction of disulfide bonds and application of mechanical stress, new disulfide bonds form in a new arrangement, stabilizing the desired conformation [Feughelman, J Soc Cosmet Chem 1990, 41:209-2120].

U.S. Patent Application Publication No. 2012/0186596 describes a use of a combination of transglutaminase and polylysine for hair straightening. The topically applied transglutaminase is reported to covalently bind the polylysine to glutamine in proteins near the hair surface, which results in a continuous film on the surface of the hair.

Cellulose nanocrystals (CNC) represent a bio-material made from cellulose, which can be obtained from waste streams such as those of paper mills and municipal sewage system sludge. In its almost pure form, CNC has a tiny crystalline molecular structure, with a 200-300 nm length and 10-20 nm width, and is about 10 times stronger than steel. CNC is a highly crystalline form of nano structured cellulose; due to the high aspect ratio, CNC fibres are typically obtained by controlled acid hydrolysis, during which the amorphous regions of the cellulose are attacked and removed. Suitably modified CNC, including CNC hydrolyzed by H ₂ S0 ₄ , self-assembles and forms nematic liquid crystals in solution [Sakurada et al., J Poly m Sci 1962, 57:651-660].

Resilin is found in specialized cuticle regions in many insects, and displays unique mechanical properties that combine reversible deformation with very high resilience. The structure of resilin is essentially an amorphous, polymeric hydrogel held together via di- and tri- tyrosine crosslinks [Qin et al., Biomaterials 2011, 32:9231-9243; Andersen, Biochimica Biophysica Acta 1964, 93:213-215], which imparts near perfect rubberiness. Qin et al. [Biomacromolecules 2009, 10:3227-3234] describe the cloning, expression and purification of resilin-chitin binding domain (6H-resilin ChBD) proteins, which lay the foundation for a resilin- cellulose binding domain (CBD) construct.

International Patent Applicant Publication WO2013/030840 describes elastomeric materials prepared from recombinant proteins comprising resilin with a chitin binding domain (resilin-ChBD) or with a cellulose binding domain (resilin-CBD), by cross-linking dihydroxyphenyl moieties. International Patent Applicant Publication WO 2015/068160 describes further artificially cross-linked elastomeric materials prepared from resilin-ChBD or resilin-CBD, as well as composite materials comprising resilin-CBD bound to nanocrystalline cellulose. Verker et al. [Cellulose 2014, 21:4369-4379] describes direct insertion of resilin-CBD bound to nanocrystalline cellulose into a hydrophobic epoxy matrix, giving a 50 % improvement in the Young's modulus and a higher elasticity of the nanocomposite compared to the neat epoxy.

U.S. Patent Application Publication No. 2010/0015070 describes a use of resilin proteins in cosmetics, wherein the proteins comprise 1-100 repeat units with the consensus sequence SXXYGXP (SEQ ID NO: 20).

Additional background art includes Abraham et al. [Surg Cosmet Dermatol 2009, 1: 178- 185]; Ardell & Andersen [Insect Biochem Mol Biol 2001, 31:965-970]; Elvin et al. [Nature 2005, 437:999-1002]; Rivkin et al. [Industrial Biotechnology 2015, 11: 144-158]; Shoseyov et al. [Microbiol Mol Biol Rev 2006, 70:283-295]; Weis-Fogh [J Mol Biol 1961, 3:520-531]; Weis- Fogh [J Mol Biol 1961, 3:648-667]; International Patent Applicant Publication WO2009/069123; and U.S. Patent Application Publication No. 2012/0125358.

SUMMARY OF THE INVENTION

According to an aspect of some embodiments of the present invention there is provided a method of straightening hair, the method comprising:

(a) applying at least one cationic agent to the hair and/or subjecting the hair to a plasma treatment;

(b) applying cellulose nanocrystals to the hair; and

(c) applying heat and pressure to the hair, at a degree sufficient to cause hair straightening without causing damage to hair,

thereby straightening the hair.

According to some of any of the embodiments described herein, the method further comprises, prior to (a), applying to the hair an agent capable of cleaving disulfide bonds in hair. According to some of any of the embodiments described herein, the method further comprises applying resilin to the hair.

According to some of any of the embodiments described herein, the resilin is a modified resilin comprising a cellulose-binding domain (CBD).

According to some of any of the embodiments described herein, the method comprises applying at least a portion of the resilin to the hair subsequently to applying the hair- straightening composition.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected at least one day subsequently to applying the hair- straightening composition.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected at least one week after applying the hair- straightening composition.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected on at least two different days.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected on at least 5 different days.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected during a time period in a range of from one week to two years after applying the hair- straightening composition.

According to some of any of the embodiments described herein, the method is for maintenance of straightened hair after each application of the hair- straightening composition and the heat and pressure.

According to an aspect of some embodiments of the present invention there is provided a hair-straightening composition comprising cellulose nanocrystals, and a carrier suitable for application to hair.

According to an aspect of some embodiments of the present invention there is provided a method for maintenance of straightened hair following a hair-straightening treatment, the method comprising applying resilin to the hair.

According to some of any of the embodiments described herein, the hair-straightening treatment comprises applying cellulose nanocrystals to the hair, for example, a treatment as described herein in any of the respective embodiments and any combination thereof.

According to some of any of the embodiments described herein, the resilin is a modified resilin comprising a cellulose-binding domain (CBD). According to some of any of the embodiments described herein, the applying of resilin to the hair is effected on at least two different days.

According to some of any of the embodiments described herein, the applying of resilin to the hair is effected on at least 5 different days.

According to some of any of the embodiments described herein, the applying of resilin to the hair is effected at least one week after applying the hair- straightening composition.

According to some of any of the embodiments described herein, the applying of at least a portion of the resilin to the hair is effected during a time period in a range of from one week to two years after applying the hair- straightening composition.

According to an aspect of some embodiments of the present invention there is provided a hair-straightening composition comprising resilin, and a carrier suitable for application to hair.

According to some of any of the embodiments described herein, the composition is for maintenance of straightened hair following a hair- straightening treatment.

According to some of any of the embodiments described herein, the hair-straightening treatment comprises applying cellulose nanocrystals to the hair, for example, a treatment as described herein in any of the respective embodiments and any combination thereof.

According to some of any of the embodiments described herein, the resilin is a modified resilin comprising a cellulose-binding domain (CBD).

According to an aspect of some embodiments of the present invention there is provided a kit for straightening hair, the kit comprising, as separate containers:

a) a first container comprising cellulose nanocrystals, and a carrier suitable for application to hair; and

b) a second container comprising a pre-treatment composition comprising at least one cationic agent.

According to some of any of the embodiments described herein, the kit further comprises a third container comprising the composition comprising resilin and a carrier suitable for application to hair.

According to some of any of the embodiments described herein, the resilin is a modified resilin comprising a cellulose-binding domain (CBD).

According to some of any of the embodiments described herein, the kit further comprises a fourth container comprising an agent capable of cleaving disulfide bonds in hair.

According to an aspect of some embodiments of the present invention there is provided a kit for straightening and maintenance of hair, the kit comprising, as separate containers: a) a first container comprising cellulose nanocrystals, and a carrier suitable for application to hair; and

b) a second container comprising resilin and a carrier suitable for application to hair. According to some of any of the embodiments described herein, the resilin is a modified resilin comprising a cellulose-binding domain (CBD).

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying images. With specific reference now to the images in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the images makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micro graphic images at xlOOO magnification (C) of the hair samples after a hair-straightening treatment using 5 mM SMBS + 0.01 % polylysine (Sample 1-1), 5 mM SMBS + polylysine + CNC (Sample 1-2), 0.5 % SDS + 1% NaCl + 5 mM SMBS + 0.5 M Cys + 2 % cetrimonium chloride (Sample 1-3), 0.5 % SDS + 1% NaCl (Sample 1-4), or 0.5 % SDS + 1% NaCl + 5 mM SMBS + 0.5 M Cys + 2 % cetrimonium chloride + CNC (Sample 1-5).

FIG. 2 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x2500 magnification (C) of the same treated hair samples as depicted in FIG. 1.

FIG. 3 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x6500 magnification (C) of the same treated hair samples as depicted in FIG. 1.

FIG. 4 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at xlOOO magnification (C) of the hair samples after a hair-straightening treatment using 5 mM SMBS + 200 mM Cys + 2 % chitosan + CNC (Sample 2-1), 5 mM SMBS + 200 mM Cys (Sample 2-2), 5 mM SMBS + 2 % chitosan (in 5 % vinegar + 0.2 M NaCl) + CNC (Sample 2-3), 5 mM SMBS + 2 % chitosan (Sample 2-4), or 5 mM SMBS + 2 % chitosan + CNC (Sample 2-5).

FIG. 5 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x2500 magnification (C) of the same treated hair samples as depicted in FIG. 4.

FIG. 6 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x6500 magnification (C) of the same treated hair samples as depicted in FIG. 4.

FIG. 7 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at xlOOO magnification (C) of the hair samples after a hair-straightening treatment using 5 mM SMBS + aldehyde-CNC (Sample 3-1), 5 mM SMBS + 0.5 M Cys + 2 % gelatin (Sample 3-2), 5 mM SMBS + 0.5 M Cys + 2 % chitosan + CNC (Sample 3-3), 5 mM SMBS + 0.5 M Cys + 0.5 M Arg + CNC (Sample 3-4), or 5 mM SMBS + 0.5 M Cys + 2 % gelatin + CNC (Sample 3-5).

FIG. 8 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x2500 magnification (C) of the same treated hair samples as depicted in FIG. 7.

FIG. 9 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x6500 magnification (C) of the same treated hair samples as depicted in FIG. 7.

FIG. 10 presents photographic images of hair samples before (A) and after (B) treatment, and scanning electron micrographic images at x 13000 magnification (C) of the same treated hair samples as depicted in FIG. 7.

FIG. 11 presents photographic images of a hair sample before and at successive stages after a hair straightening treatment (using 1 M cysteine, 0.5 M arginine in 1 % BTMS, and 3 % CNC), as follows: before (image 1) and immediately after (image 2) treatment, after washing with water (image 3) and 5 times with SLS-free shampoo (images 4, 5, 6, 7, 8) over the course of about 2.5 weeks after treatment, followed by washing with 4 mg/ml (image 9) and 2 mg/ml (image 10) RES-CBD (resilin with cellulose binding domain) in water over the course of one week, and washing 4 times with SLS-free shampoo and 1 mg/ml RES-CBD in water over the course of 2 weeks (images 11, 12, 13, 14), followed by application of 50 mg/ml RES-CBD (image 15), and (over the course of about 3 weeks) alternating washes with SLS-free shampoo and 2 mg/ml RES-CBD in water (images 16, 18, 21, 22 and 25), application of 10 mg/ml RES- CBD (images 17, 19, 20, 23, 24) (images 19 and 23 show hair before washing with water after RES-CBD treatment, and images 17, 20 and 24 show hair after washing with water).

FIG. 12 presents photographic images of a hair sample about 3 months after an exemplary hair straightening treatment, before (FIG. 12A) and several hours after (FIG. 12B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 12C), SLS-free shampoo (FIG. 12D), and again with SLS- free shampoo (FIG. 12E).

FIG. 13 presents photographic images of a hair sample about 3 months after an exemplary hair straightening treatment, before (FIG. 13A) and several hours after (FIG. 13B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 13C), SLS-free shampoo (FIG. 13D), and again with SLS- free shampoo (FIG. 13E).

FIG. 14 presents photographic images of a hair sample about 2 months after an exemplary hair straightening treatment, before (FIG. 14A) and several hours after (FIG. 14B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 14C), SLS-free shampoo (FIG. 14D), and again with SLS- free shampoo (FIG. 14E).

FIG. 15 presents photographic images of a hair sample about 3 weeks after an exemplary hair straightening treatment, before (FIG. 15A) and several hours after (FIG. 15B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 15C), SLS-free shampoo (FIG. 15D), and again with SLS- free shampoo (FIG. 15E).

FIG. 16 presents photographic images of a hair sample about one month after an exemplary hair straightening treatment, before (FIG. 16A) and several hours after (FIG. 16B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 16C), SLS-free shampoo (FIG. 16D), and again with SLS-free shampoo (FIG. 16E).

FIG. 17 presents photographic images of a hair sample about 3 months after an exemplary hair straightening treatment, before (FIG. 17A) and several hours after (FIG. 17B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 17C), SLS-free shampoo (FIG. 17D), and again with SLS- free shampoo (FIG. 17E). FIG. 18 presents photographic images of a hair sample about one month after an exemplary hair straightening treatment, before (FIG. 18A) and several hours after (FIG. 18B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 18C) and SLS-free shampoo (FIG. 18D).

FIG. 19 presents photographic images of a hair sample about 1.5 months after an exemplary hair straightening treatment, before (FIG. 19A) and several hours after (FIG. 19B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 19C), SLS-free shampoo (FIG. 19D), and again with SLS-free shampoo (FIG. 19E).

FIG. 20 presents photographic images of a hair sample about 2 months after an exemplary hair straightening treatment, before (FIG. 20A) and several hours after (FIG. 20B) application of 10 mg/ml RES-CBD (resilin with cellulose binding domain) in water, followed by washing (at intervals of 2 days) with water (FIG. 20C), SLS-free shampoo (FIG. 20D), and again with SLS- free shampoo (FIG. 20E).

FIGs. 21A-D present scanning electron micrographic images of untreated hair sample at xlOOO magnification (FIG. 21A) and at x6,500 magnification (FIG. 21B) and of the hair sample following sequential treatment with 1M cysteine in 100 mM MES pH 3.5, 0.5M arginine in 1% BTMS in DDW, and 2 % CNC, at xlOOO magnification (FIG. 21C) and at x6,500 magnification (FIG. 21D).

FIGs. 22A-D present scanning electron micrographic images of untreated hair sample at xlOOO magnification (FIG. 22A) and at x23,000 magnification (FIG. 22B) and of the hair sample following sequential treatment with 1M cysteine in 100 mM MES pH 3.5, 0.5M arginine in 1% BTMS, and 3 % CNC, at xlOOO magnification (FIG. 22C) and at x23,000 magnification (FIG. 22D).

FIGs. 23A-E present scanning electron micrographic images of untreated hair sample at xlOOO magnification (FIG. 23A) and at x23,000 magnification (FIG. 23B) and of the hair sample following sequential treatment with 1M cysteine in 100 mM MES pH 3.5, 0.5M arginine in 1% BTMS in DDW and 2% CNC containing 10: 1 RES-CBD, at xlOOO magnification (FIG. 23C) and at x23,000 magnification (FIG. 23D), and of a side incision of the treated hair sample at x23,000 magnification (FIG. 23E).

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to cosmetics, more particularly, but not exclusively, to compositions and treatments useful in straightening hair. Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

The present inventors have uncovered that cellulose nanocrystals are surprisingly effective for use in straightening hair, and can enhance the efficacy of existing techniques for straightening hair.

While reducing the present invention to practice, the inventors have further uncovered that application of resilin to hair is surprisingly effective at enhancing and restoring the hair- straightening effect of treatments utilizing cellulose nanocrystals, even when applied many weeks after the original hair- straightening treatment.

Without being bound to any particular theory, it is believed that the cellulose nanocrystals affect the hair by forming a rigid or semi-rigid film, long-lasting coating on the hair surface.

According to an aspect of some embodiments of the invention, there is provided a method of straightening hair, the method comprising applying cellulose nanocrystals (CNC) to the hair, in combination with conditions suitable for altering a shape of hair, for example, by applying heat and pressure to the hair, preferably at a degree sufficient to cause hair straightening without causing damage to hair.

Herein, a "degree" of an applied heat and/or pressure encompasses a temperature (regarding applied heat), duration (of heat and/or pressure), and/or amount (e.g., of pressure).

Suitable degrees of heat and pressure for effecting hair-straightening, as well as devices (e.g., hot irons) and techniques suitable for applying such heat and pressure, will be known to one of ordinary skill in the art.

The cellulose nanocrystals utilized in any of the embodiments of the invention may optionally be chemically non-modified (which does not exclude naturally-occurring chemical modifications commonly present in cellulose nanocrystals, such as the presence of sulfate groups) or modified. Various suitable forms of modified cellulose nanocrystals are described elsewhere herein.

Hair-straightening treatment according to any of the respective embodiments described herein optionally comprises one or more pre-treatment stages, performed prior to and/or concomitantly with (preferably prior to) application of cellulose nanocrystals. Examples of such pre-treatments include, without limitation, treatments with cationic agents and/or with plasma (e.g., by subjecting the hair to an air plasma jet, using any suitable device).

Thus, in some embodiments, the method comprises: a) applying at least one cationic agent to the hair and/or subjecting the hair to a plasma treatment;

b) applying cellulose nanocrystals to the hair; and

c) applying heat and pressure to the hair, at a degree sufficient to cause hair straightening without causing damage to hair.

The hair is optionally washed after pre-treatment (e.g., pre-treatment with a cationic agent), and optionally both washed and dried, prior to applying cellulose nanocrystals.

Examples of suitable cationic compounds include, without limitation, amino acids, such as arginine and lysine; cationic polymers, such as chitosan, polylysine (e.g., poly-L-lysine) and polyethyleneimine (PEI); and cationic surfactants, such as behentrimonium salts (e.g., behentrimonium methosulfate (BTMS), cetrimonium (a.k.a. cetyltrimethylammonium, hexadecyltrimethylammonium or HDTMA) salts (e.g., cetrimonium chloride or cetrimonium bromide (CTAB)) and cetylpyridinium salts (e.g., cetylpyridinium chloride (CPC)), and any combination of the foregoing.

Without being bound by any particular theory, it is believed that the surface of CNC is negatively charged (e.g., by sulfate groups introduced during CNC production CNC) and that cationic compounds bind to the negatively charged surface of CNC and/or hair via coulombic attraction, thereby facilitating binding of CNC to the hair surface. It is further believed that cationic surfactants can facilitate binding of CNC to the hair surface by binding to the negatively charged surface of CNC via coulombic attraction and to the hair surface via hydrophobic interactions (as the hair surface is naturally hydrophobic due to the presence of lipids such as 18- methyl eicosanoic acid (18-MEA).

Alternatively or additionally, pre-treatment may optionally comprise plasma treatment - for example, cold plasma treatment - for modifying the hair surface. Plasma treatments are known in the art to be particularly suitable for modifying surface properties without significantly affecting bulk properties.

Plasma treatment may optionally be used to introduce positive charges to the hair surface, in addition to or instead of use of cationic agents.

In some embodiments of any of the respective embodiments described herein, the hair- straightening treatment further comprises applying an agent capable of cleaving disulfide bonds in hair, for example, by reducing disulfide bonds to two free thiol groups or derivatives of thiol groups. Such agents are also collectively referred to herein interchangeably as "a reducing agent". Examples of suitable agents capable of cleaving disulfide bonds in hair include, without limitation, sulfites and bisulfites (e.g., ammonium sulfite, ammonium bisulfite), metabisulfites (e.g., sodium metabisulfite), and thiols such as cysteine and thioglycolate (e.g., ammonium thioglycolate), and any combination of the foregoing. Sodium metabisulfite (SMBS; Na ₂ S205) is an exemplary agent for reducing disulfide bonds.

Agents capable of cleaving disulfide bonds in hair are commonly used to facilitate reconfiguration of the keratin in the hair, thereby allowing a straighter hair conformation. All these agents are contemplated herewith.

Without being bound by any particular theory, it is believed that cellulose nanocrystals on the hair enhance the ability of the abovementioned agents to permanently or semi-permanently reconfigure the keratin structure in the hair, by providing mechanical support to the newly formed keratin structure upon straightening and/or by shielding the hair from ambient humidity and/or pollution, which may weaken the effect of the reconfiguration of keratin structure.

In some embodiments of any of the embodiments described herein, the method of straightening hair further comprises applying resilin (as defined herein) to the hair.

In some embodiments, at least a portion of the resilin applied to the hair (according to any of the respective embodiments described herein) is applied subsequently to applying the cellulose nanocrystals (e.g., as part of a composition described herein), for example, at least one day, at least one week and/or at least one month after applying the cellulose nanocrystals. In some such embodiments, the resilin is applied during a time period of up to 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 months, or even up to 2 years or more, after applying the cellulose nanocrystals.

In some embodiments of any of the embodiments described herein relating to application of resilin subsequently to applying a hair- straightening composition, the application of resilin is for maintenance of straightened hair after straightening the hair by applying the hair- straightening composition (e.g., along with heat and pressure according to any of the respective embodiments described herein).

Herein, "maintenance" (or "maintaining" or variants thereof) of straightened hair refers to delaying (e.g., decreasing a rate of) and/or at least partially reversing (e.g., temporarily reversing) a process whereby the effect of hair straightening treatment on the shape of hair is gradually lost.

Thus, for each time the hair is straightened (to obtain straightened hair), application of resilin (according to any of the respective embodiments described herein) may optionally be effected thereafter once, twice (e.g., on two different days), or 3, 4, 5, 6, 7, 8, 9, 10 or more times (e.g., on different days), so as to maintain the previously straightened hair in a straightened state. For example, application of resilin can be effected once a day, every day after the hair straightening treatment, for, for example, 1, 2, 3, 4, 5, 6, 7, days, or more, or for 2 weeks, 3 weeks, 4 weeks, or more, as desired. Alternatively, application of resilin can be effected every other day after the hair straightening treatment, for a time period as desired (e.g., as indicated hereinabove). Further alternatively, application of resilin can be effected once, twice, or trice, as week, after the hair straightening treatment, for a time period as desired (e.g., as indicated hereinabove).

According to an aspect of some embodiments of the invention, there is provided a method for maintenance of straightened hair following a hair-straightening treatment, the method comprising applying resilin to the hair, according to any of the respective embodiments described herein. The hair-straightening treatment is optionally according to any of the embodiments described herein relating to a hair-straightening treatment (e.g., utilizing application of cellulose nanocrystals), or alternatively, may be any other hair-straightening treatment known in the art.

In some of any of the embodiments relating to maintenance of straightened hair, the resilin is applied to the hair (according to any of the respective embodiments described herein) at least one day, at least one week and/or at least one month after the hair-straightening treatment. In some such embodiments, the resilin is applied during a time period of up to 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 months, or even up to 2 years or more, after the hair-straightening treatment.

It is expected that during the life of a patent maturing from this application many relevant hair-straightening treatments will be developed and the scope of the term "hair-straightening treatment" is intended to include all such new technologies a priori, except where such a treatment is clearly excluded from a described embodiment.

According to an aspect of some embodiments of the present invention there is provided a method of straightening hair, which comprises subjecting the hair to a first hair-straightening treatment (e.g., a hair-straightening treatment according to any of the embodiments described herein relating to a hair-straightening treatment utilizing application of cellulose nanocrystals, or alternatively, by any other hair-straightening treatment known in the art, as described herein); applying resilin to the hair following the first hair-straightening treatment, according to any of the respective embodiments described herein;

subjecting the hair to a second hair-straightening treatment as described herein in any of the respective embodiments of the first treatment; and

applying resilin to the hair following the first hair-straightening treatment, according to any of the respective embodiments described herein, and optionally, subjecting the hair to third, fourth, fifth, etc. hair-straightening treatments, as desired, while applying resilin following each treatment,

such that a time period between consecutive treatments is longer by at least 20 %, or at least 30 %, or at least 40 %, or at least 50 %, or more, than the time period between the same consecutive treatments without application of resilin following each treatment required for maintaining straightened hair as desired by a subject.

In some embodiments, the time period between each of the first and second hair- straightening treatments, and/or between each of the second and third treatments, and/or between the third and fourth treatments, and so on, that is, between consecutive treatments, is at least 4 weeks, or at least 8 weeks, or at least 3 months, or at least 6 month, or at least 8 months, or at least 10 months, or at least one year, or even more (e.g., 2 years).

This method utilizes the maintenance effect provided by the application of resilin by enabling a reduced frequency of hair- straightening treatments that are required or desired for maintaining straightened hair.

In some of any of the embodiments described herein, in any of the relevant methods described herein a modified and/or non-modified CNC (according to any of the respective embodiments described herein) is applied in a composition comprising same, as described in further detail hereinunder. In some embodiments, a concentration of the modified and/or non- modified CNC in the composition ranges from about 0.1 % to about 5 %, by weight, including any intermediate values and subranges therebetween.

In some of any of the embodiments described herein, in any of the relevant methods described herein, a resilin (according to any of the respective embodiments described herein) is applied in a composition comprising same, as described in further detail hereinunder. In some embodiments, a concentration of the resilin in the composition ranges from about 0.1 mg/ml to about 200 mg/ml, including any intermediate values and subranges therebetween.

In some of any of the embodiments described herein, in any of the relevant methods described herein, a reducing agent (according to any of the respective embodiments described herein) is applied in a composition comprising same, as described in further details hereinunder. In some embodiments, a concentration of the reducing agent in the composition ranges from about 1 nM to 2M, including any intermediate values and subranges therebetween.

In some of any of the embodiments described herein, in any of the relevant methods described herein a cationic agent (according to any of the respective embodiments described herein) is applied in a composition comprising same, as described in further details hereinunder. In some embodiments, a concentration of the cationic agent in the composition ranges from about 0.1 % to about 40 %, by weight, including any intermediate values and subranges therebetween.

In some of any of the embodiments described herein, an amount of any of the agents or compositions comprising same that applied to the hair depends on the type, length, curliness, width, and other factors of the hair of an individual subject. Those skilled in the art would readily determine which amounts would provide desired results for an individual subject.

Modified cellulose nanocrystals:

In some embodiments of any of the embodiments described herein relating to CNC, the CNC optionally comprises chemically modified CNC. Modifications of CNC may optionally be selected so as to provide a desired stiffness/flexibility of a CNC film applied onto hair, and/or a desired hydrophobicity/hydrophilicity.

A wide variety of techniques for modifying cellulose are known in the art (e.g., by covalently modifying hydroxyl groups at the cellulose surface), and may optionally be used in the context of some embodiments of the invention. Examples of such modifications include, without limitation, esterification (e.g., according to procedures such described by Zoppe et al. [Biomacromolecules 2010, 11:2683-2691] or Habibi et al. [J Mater Chem 2008, 18:5002-5010]), etherification with alkylating agents (e.g., according to procedures such described by Hermanson GT [Bioconjugate Techniques, (Academic, San Diego, 1996)]), oxidation (e.g., according to procedures such as described by Azzam et al. [Biomacromolecules 2010, 11:3652-3659]), silylation (e.g., according to procedures such as described by Taipina et al. [Cellulose 2013, 20:217-226]), reaction with isocyanates (e.g., according to procedures such described by Shang et al. [Cellulose 2013, 20: 179-190] or Yu et al. [ACS Sustainable Chem Eng 2014, 2:875-886]), and/or polymer grafting (e.g., according to procedures such described by Shang et al. [Cellulose 2013, 20: 179-190], Zoppe et al. [Biomacromolecules 2010, 11:2683-2691], Habibi et al. [J Mater Chem 2008, 18:5002-5010] or Azzam et al. [Biomacromolecules 2010, 11:3652-3659]).

In some of any of the respective embodiments described herein, the modified CNC is modified by the addition of an acryl or methacryl functional group (referred to herein as "(meth)acryl" or a variant thereof).

The (meth)acryl group may optionally be attached directly to the cellulose by an ester linkage (-0-C(=0)-), for example, by contacting CNC with a reagent such as (meth)acrylic anhydride, (meth)acryl chloride, and the like.

Alternatively or additionally, the may optionally be attached to the cellulose via a linking moiety, for example, by contacting CNC with a reagent such as glycidyl (meth)acrylate or isocyanatoethyl (meth)acrylate, under suitable conditions (e.g., in the presence of a base such as triethylamine or sodium hydroxide), optionally aqueous conditions.

In some of any of the respective embodiments described herein, the modified CNC is modified by a polyester network on the CNC surface, for example, a castor oil-based polyol (COPO). The polyester is optionally attached to the CNC via a diisocyanate linker, for example, a diisocyanate (e.g., toluene diisocyanate) linker such as described by Shang et al. [Cellulose 2013, 20: 179-190].

In some of any of the respective embodiments described herein, the modified CNC is modified by the addition of a hydrophobic functional group, optionally attached to the cellulose by an ester linkage (-0-C(=0)-). Hydrophobic ester groups (e.g., Cg-so-acyl) may be formed, for example, by contacting CNC with a reagent such as a fatty acyl chloride, an alkyl ketene dimer (which forms beta-ketocarboxylic ester groups), or an alkenyl succinic anhydride, or any other suitable agent used in the art to modify cellulose (e.g., in paper sizing processes).

In some of any of the respective embodiments described herein, the modified CNC is modified by the addition of a thiol functional group. Many agents (e.g., "thiolating agents") and techniques suitable for introducing thiol groups are known in the art.

In some embodiments, modified cellulose nanocrystals comprising a thiol group are attached to keratin in the hair via disulfide bonds formed between cysteine in the keratin and the cellulose nanocrystal thiol. Alternatively or additionally, modified cellulose nanocrystals comprising a thiol group are attached to each other, so as to cross-link the cellulose nanocrystals.

Such disulfide bonds are optionally formed by contacting the CNC with a suitable oxidizing agent. Suitable oxidizing agents for forming disulfide bonds in hair are known in the art, and are often used at the end of hair-straightening treatments (e.g., to stabilize the newly straightened hair conformation).

Thiol groups may optionally be utilized for further modification of CNC, for example, by reacting with haloacetyl, alkyl halide, maleimide, and/or aziridine groups.

In some of any of the respective embodiments described herein, modification comprises oxidizing cellulose, so as to obtain aldehyde groups and/or carboxylate groups (in addition to or instead of the naturally occurring hydroxyl groups of cellulose). For example, aldehyde groups may be obtained by periodate-oxidation of glucose residues in cellulose (e.g., as exemplified herein).

The aldehyde groups and/or carboxylate groups are optionally used to react with agents which comprise a desired functional group as well as a functional group (e.g., amine) for attaching to the aldehyde or carboxylate, which may not be as readily attached to CNC. For example, amine groups can be reacted with carboxylates to form an amide linkage, using common techniques (e.g., using a carbodiimide such as l-ethyl-3-(3- dimethylaminopropyl)carbodiimide (EDC), and with aldehydes to form an imine. Aldehyde groups on cellulose can also be sulfonated by upon reaction with bisulfite (e.g., as described by Liimatainen et al. [Cellulose 2013; 20:741-749]).

Carbodiimide (e.g., EDC) coupling is optionally effected under acidic (e.g., pH 4.5-5.5) conditions, such as in a MES (2-(N-morpholino)ethanesulfonic acid), although phosphate buffers at pH < 7.2 are also compatible with the reaction chemistry. N-hydroxysuccinimide (NHS) or its water-soluble analog (sulfo-NHS) is optionally included in carbodiimide coupling protocols to improve efficiency and/or to create a more stable, amine-reactive intermediate.

In some embodiments, a polypeptide (e.g., silk or resilin protein), according to any of the respective embodiments described herein, is attached to CNC via one or more amine groups in the polypeptide, for example, via carbodiimide coupling (e.g., any of the respective embodiments described herein).

In some embodiments, oxidized CNC (e.g., NaC10 ₂ -oxidized CNC) comprising carboxylate groups is reacted with a compound comprising an amine group linked to a thiol group (e.g., via a hydrocarbon linker such as C ₂ -Cio alkylene, as in 6-amino-l-hexanethiol), using carbodiimide coupling, so as to obtain thiol groups attached to the CNC via amide linkages (- C(=0)-NH-).

In some embodiments, oxidized CNC (e.g., NaC10 ₂ -oxidized CNC) comprising carboxylate groups is reacted with a compound comprising an amine group linked to a thiol group (e.g., via a hydrocarbon linker such as C ₂ -Cio alkylene, as in 6-amino-l-hexanethiol), using carbodiimide coupling, so as to obtain thiol groups attached to the CNC via amide linkages (- C(=0)-NH-).

CNC may also be modified (e.g., by attachment to a polypeptide) via click chemistry, e.g., as described by Karaaslan et al. [Cellulose 2013, 20:2655-2665].

Alternatively or additionally to any of the covalent modifications described herein, the cellulose nanocrystals may optionally be modified non-covalently, for example, by attachment (e.g., adsorption) of compounds to a surface thereof by noncovalent bonds (e.g., hydrophobic interactions, hydrogen bonds, and/or electrostatic interactions), and/or by coating a surface of the crystals with a polymer.

In some embodiments of any of the respective embodiments described herein, the cellulose nanocrystals are attached non-covalently to a polypeptide, for example, a polypeptide comprising a cellulose binding domain (e.g., according to any of the respective embodiments described herein). The cellulose binding domain (CBD) is optionally incorporated into a protein, for example, a silk or resilin protein. Resilin with a CBD is an exemplary protein suitable for noncovalent modification of cellulose nanocrystals.

CBD (cellulose binding domain) belongs to a large superfamily of carbohydrate-binding molecules (CBMs), and represents a contiguous amino acid sequence within carbohydrate-active enzymes. The domain features a discrete fold, carbohydrate (cellulose)-binding activity, and has been found in both hydrolytic and non-hydrolytic proteins. The utilization of CBDs is described, for example, by Shoseyov et al. [Microbiol Mol Biol Rev 2006, 70:283-295], which is incorporated herein by reference.

Examples of cellulose binding domain (CBD) amino acid sequences are provided in SEQ

ID NOs: 17, 18 and 21, and in Yaniv et al. [Acta Crystallogr Sect F Struct Biol Cryst Commun 2013, 69:733-737] (e.g., PDB: 4J05-A).

Without being bound by any particular theory, it is believed that proteins such as silk and resilin can provide elasticity and resilience, for example, to a layer of CNC on the hair surface.

Silk protein according to any of the respective embodiments described herein optionally comprises spider silk protein, and optionally spider dragline silk protein. The spider silk protein is optionally a recombinant protein fused to CBD.

A silk polypeptide (with or without a CBD) may optionally comprise any silk polypeptide described in International Patent Application Publication WO 2009/069123, the contents of which are incorporated herein by reference.

Fusion of CBD to silk protein can dramatically improve protein properties, such as its molecular order and melting point. The highly ordered crystalline cellulose structure optionally serves as a template to enable the assembly of silk proteins into hair fibers. This can optionally be facilitated by the fusion of silk proteins to CBD, thereby facilitating film assembly of silk- CBD and/or CNC over hair fibers.

Cross-linking cellulose nanocrystals:

In some embodiments of any of the embodiments described herein relating to a method of straightening hair by applying cellulose nanocrystals (CNC) to the hair, the method further comprises cross-linking the cellulose nanocrystals on the hair.

Without being bound by any particular theory, it is believed that cross-linking cellulose nanocrystals on the hair results in a more rigid and/or durable layer coating the hair surface, thereby enhancing the effect of the cellulose nanocrystals (e.g., as a surface barrier and/or as a mechanical support of hair-straightening). Cross-linking may optionally be effected by contacting the cellulose nanocrystals with a suitable cross-linking agent, for example, during and/or after application of the cellulose nanocrystals onto the hair. Alternatively or additionally, cross-linking may be effected by irradiating the cellulose (e.g., by UV and/or visible light), for example, chemically modified cellulose nanocrystals selected to be cross -linkable upon irradiation.

Cross-linking may optionally be effected prior to, concomitantly with and/or subsequently to applying heat and pressure to straighten the hair.

In some embodiments of any of the respective embodiments, cross-linking is effected by UV irradiation at a sufficient dosage (e.g., intensity and/or duration) to effect cross-linking of the CNC. In some such embodiments, the CNC is a modified CNC comprising a UV-cross-linkable functional group such as a (meth)acrylate functional group (e.g., according to any of the respective embodiments described herein).

Irradiation is optionally effected in the presence of a photoinitiator (e.g., a water-soluble photoinitiator, such as Irgacure™ 2959). The photoinitiator may optionally be applied to the hair along with the CNC, for example, wherein the photoinitiator is co-formulated with the CNC in a composition described herein.

Irradiation with UV and/or visible light may optionally be effected by a practitioner of a hair-straightening treatment (e.g., a hairdresser or employee thereof). Alternatively or additionally, the irradiation is effected by exposure to natural sunlight.

Examples of suitable cross-linking agents which may be used to cross-link cellulose nanocrystals include, without limitation, alpha-hydroxyacids (e.g., lactic acid, glycolic acid, malic acid, citric acid, tartaric acid, and derivatives thereof), which may optionally promote esterification/transesterification cross-linking reactions at the CNC interface; compounds with two or more carboxylic acid groups (e.g., adipic acid, azelaic acid, succinic acid, malic acid, tartaric acid, citric acid, BTCA (1,2,3,4-butanetetracarboxylic acid), and derivatives thereof), which may be esterified (e.g., according to any of the respective embodiments described herein) to hydroxyl groups of different cellulose nanocrystals; and proteins (e.g., casein, albumin, gelatin, resilin).

Oxidizing agents may optionally be used to cross -link modified CNC with thiol groups (e.g., as described herein).

Polypeptides such as proteins (e.g., casein, albumin, gelatin, keratin) may optionally cross-link CNC upon application of heat via condensation reactions such as esterification (e.g., between polypeptide carboxylate groups and hydroxyl groups on CNC and/or another polypeptide). Alternatively or additionally, the polypeptide (e.g., resilin) cross-links CNC (e.g., CNC oxidized to comprise carboxylate groups) via carbodiimide (e.g., EDC) coupling. Alternatively, or additionally the polypeptide (e.g., gelatin) cross-links the CNC in the presence of a transglutaminase which is naturally present in or applied to the hair.

Cross-linking nanocrystals with polypeptides may optionally be effected by attaching a polypeptide molecule to two or more nanocrystals (e.g., by condensation, and/or carbodiimide coupling), and/or by attaching (e.g., by condensation, carbodiimide coupling, and/or transglutaminase) a polypeptide molecule attached to a nanocrystal (e.g., by condensation, and/or carbodiimide coupling) to another polypeptide molecule attached to another nanocrystal.

A polypeptide used to cross-link CNC according to any of the respective embodiments described herein may optionally bind to the CNC covalently (e.g., according to any of the embodiments described herein relating to covalent modification of CNC).

Alternatively or additionally, a polypeptide used to cross-link CNC according to any of the respective embodiments described herein may optionally bind to the CNC non-covalently (e.g., according to any of the embodiments described herein relating to noncovalent modification of CNC), for example, wherein the polypeptide comprises a cellulose binding domain (e.g., a modified resilin or silk, or an isolated cellulose binding domain polypeptide). In such embodiments, the cross-linking may be effected by covalently cross-linking a plurality of polypeptides non-covalently attached to CNC, for example, by condensation, carbodiimide coupling, and/or transglutaminase (according to any of the respective embodiments described herein).

In some of any of the embodiments described herein, in any of the relevant methods described herein, the modified and/or non-modified CNC is employed in combination with a cross-linking agent as described herein. In some embodiments, the CNC and the cross-linking agent are applied concomitantly, or sequentially, in any order. A concentration ratio between the CNC and the cross-linking agent can be determined in accordance with the chemical composition of the cross-linking agent and the desired degree of cross-linking. Exemplary such ratios may range from 100: 1 to 1: 1.

If a cross-linking agent is employed, it can form a part of a composition comprising same, as described in further detail hereinunder.

Resilin:

Herein, the term "resilin" encompasses a polypeptide comprising a sequence of a naturally-occurring resilin protein, a fragment of a naturally-occurring resilin protein, or a homologous polypeptide thereof (i.e., a polypeptide homologous to a resilin protein or fragment thereof, as defined herein). Herein, a "homologous polypeptide" of a given polypeptide encompasses polypeptides which are at least 50 %, at least 55 %, at least 60 %, at least 65 %, at least 70 %, at least 75 %, at least 80 %, at least 85 %, at least 87 %, at least 89 %, at least 91 %, at least 93 %, at least 95 % or more, e.g., 100 %, homologous to the given polypeptide, such as a resilin protein described herein (e.g., a sequence listed in Table 1 or a fragment thereof), as determined using BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters. The homologous polypeptide may also refer to a deletion, insertion, or substitution variant, including an amino acid substitution, thereof and biologically active polypeptide fragments thereof.

In some of any of the embodiments described herein, a homologous polypeptide is at least 80 % homologous, as defined hereinabove. In some embodiments, a homologous polypeptide is at least 85 % homologous, as defined hereinabove. In some embodiments, a homologous polypeptide is at least 90 % homologous, as defined hereinabove. In some embodiments, a homologous polypeptide is at least 95 % homologous, as defined hereinabove. In some embodiments, a homologous polypeptide is at least 98 % homologous, as defined hereinabove. In some embodiments, a homologous polypeptide is at least 99 % homologous, as defined hereinabove.

In some of any of the embodiments described herein, a fragment of a resilin protein (or homologous polypeptide thereof) is at least 50 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 60 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 70 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 80 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 100 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 125 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 150 amino acid residues in length. In some embodiments, a fragment of a resilin protein is at least 200 amino acid residues in length.

In some of any of the embodiments described herein, the resilin (according to any of the respective embodiments described herein) consists essentially of a naturally-occurring resilin protein, a fragment thereof, or a homologous polypeptide thereof.

In some of any of the embodiments described herein, the resilin according to any of the respective embodiments described herein) comprises one or more peptide sequence(s) in addition to a naturally-occurring resilin sequence, a fragment thereof, or a homologous polypeptide thereof.

GenBank Accession Nos. of non-limiting examples of resilin are listed in Table 1 below. Table 1

According to some of any of the embodiments described herein, the resilin (according to any of the respective embodiments described herein) comprises the full length resilin amino acid sequence (i.e. comprises amino acids from each of exon 1, exon 2 and exon 3), for example, as set forth in SEQ ID NO: 19.

According to other embodiments, the resilin (according to any of the respective embodiments described herein) comprises an exon 1 resilin amino acid sequence (SEQ ID NOs: 1, 2 or 16), or a homologous polypeptide sequence, which may be 70 % homologous, 75 % homologous, 80 % homologous, 85 % homologous, 90 % homologous, 91 % homologous, 92 % homologous, 93 % homologous, 94 % homologous, 95 % homologous, 96 % homologous, 97 % homologous, 98 % homologous, 99 % homologous or 100 % homologous to the sequence as set forth in SEQ ID NOs: 1, 2 or 16 as determined using BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters). The homologous polypeptide sequence may also refer to a deletion, insertion, or substitution variant, including an amino acid substitution, thereof and biologically active polypeptide fragments thereof.

In some of any of the embodiments described herein, the resilin (according to any of the respective embodiments described herein) is a modified resilin comprising a cellulose binding domain (CBD).

In some of any of the embodiments described herein, the resilin amino acid sequence (according to any of the respective embodiments described herein) comprises an exon 1 resilin amino acid sequence and a polysaccharide binding domain (e.g. a cellulose binding domain (CBD) and/or a chitin binding domain (ChBD), such as that encoded in exon 2). Herein, the phrase "polysaccharide-binding domain" refers to a polypeptide or a portion thereof which is capable of selectively binding to a polysaccharide. Various polysaccharide- binding domains are known in the art.

An example of a ChBD sequence found in exon 2 of resilin is provided in SEQ ID NO: 3 or 6.

In some of any of the embodiments described herein, the resilin (according to any of the respective embodiments described herein) is a modified resilin comprising a cellulose binding domain (CBD).

Examples of cellulose binding domain (CBD) amino acid sequences are provided in SEQ ID NOs: 17 and 18.

Another example of a cellulose binding domain (CBD) amino acid sequence is a sequence homologous to the sequence as set forth in SEQ ID NO:21 (as determined using BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters), which may be 70 % homologous, 75 % homologous, 80 % homologous, 85 % homologous, 90 % homologous, 91 % homologous, 92 % homologous, 93 % homologous, 94 % homologous, 95 % homologous, 96 % homologous, 97 % homologous, 98 % homologous, 99 % homologous or 100 % homologous to the sequence as set forth in SEQ ID NO:21. The homologous polypeptide sequence may also refer to a deletion, insertion, or substitution variant, including an amino acid substitution, thereof and biologically active polypeptide fragments thereof.

Without being bound by any particular theory, it is believed that a cellulose binding domain in a resilin is useful for facilitating adherence of applied resilin to applied cellulose nanocrystals, e.g., in the context of any of the respective embodiments described herein.

Additional polysaccharide binding domains are provided in International Patent Application Publication WO 2009/069123, incorporated herein by reference.

The polysaccharide binding domain may be linked to the C terminal domain of exon 1 or the N terminal domain of exon 1 (either directly or via a linker).

According to still other embodiments, the resilin amino acid sequence (according to any of the respective embodiments described herein) comprises at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least ten, at least eleven, at least twelve, at least thirteen, at least fourteen, at least fifteen, at least sixteen, at least seventeen or more resilin repeating units as set forth in SEQ ID NO: 20, and optionally as set forth in SEQ ID NO: 4 (Gly Gly Arg Pro Ser Asp Ser Tyr Gly Ala Pro Gly Gly Gly Asn).

According to still other embodiments the resilin amino acid sequence (according to any of the respective embodiments described herein) comprises at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least ten, at least eleven, at least twelve, at least thirteen, at least fourteen, at least fifteen, at least sixteen, at least seventeen or more resilin repeating units as set forth in SEQ ID NO: 5 (GRPSDSYGA).

According to still other embodiments the resilin amino acid sequence (according to any of the respective embodiments described herein) is devoid of an exon 3 amino acid sequence.

According to yet other embodiments, the resilin amino acid sequence (according to any of the respective embodiments described herein) comprises an exon 3 amino acid sequence.

Examples of polynucleotides which can be used to express resilin are set forth in SEQ ID NO: 7, 8, 10, 12 and 14.

Examples of 6H-tagged resilin polypeptide sequences are set forth in SEQ ID NO: 9, 11,

13 and 15. SEQ ID NO: 13 is an exemplary polypeptide sequence. Such sequences may be readily isolated utilizing the 6H-tag, and may be incorporated as is in the composition-of-matter or incorporated after removing the 6H-tag, for example, as described in International Patent Applicant Publication WO 2015/068160, which is incorporated herein by reference (particularly with respect to resilin sequences described therein).

Other exemplary polypeptide and polynucleotide sequences, that may be used in the context of any of the embodiments described herein relating to resilin, are provided in International Application Publication WO 2009/069123 and in International Patent Application Publication WO 2013/030840, which are incorporated herein by reference.

In some of any of the embodiments described herein, a mol ratio of a resilin as described herein and CNC ranges from 1: 1 to 1:50, or from 1: 1 to 1:20, or from 1:5 to 1:20, including any intermediate value and subranges therebetween.

Polypeptides:

The term "polypeptide" as used herein encompasses native peptide macromolecules (e.g., a resilin or silk polypeptide), including degradation products, synthetically prepared peptides and recombinant peptides (e.g., recombinantly expressed in a microorganism), as well as peptidomimetic macromolecules (typically, synthetically synthesized peptides), as well as peptoid and semipeptoid macromolecules which are peptide analogs, which may have, for example, modifications rendering the polypeptides more stable. Such modifications include, but are not limited to N-terminus modification, C-terminus modification, peptide bond modification, backbone modifications, and residue modification. Methods for preparing peptidomimetic compounds are well known in the art and are specified, for example, in Quantitative Drug Design, C.A. Ramsden Gd., Chapter 17.2, F. Choplin Pergamon Press (1992), which is incorporated by reference as if fully set forth herein. Further details in this respect are provided herein below.

Peptide bonds (-CO-NH-) within the polypeptide may be substituted, for example, by N- methylated amide bonds (-N(CH3)-CO-), ester bonds (-C(=0)-0-), ketomethylene bonds (-CO- CH ₂ -), sulfinylmethylene bonds (-S(=0)-CH ₂ -), a-aza bonds (-NH-N(R)-CO-), wherein R is any alkyl (e.g. methyl), amine bonds (-CH ₂ -NH-), sulfide bonds (-CH ₂ -S-), ethylene bonds (-CH ₂ - CH ₂ -), hydroxyethylene bonds (-CH(OH)-CH ₂ -), thioamide bonds (-CS-NH-), olefinic double bonds (-CH=CH-), fluorinated olefinic double bonds (-CF=CH-), retro-amide bonds (-NH-CO-), peptide derivatives (-N(R)-CH ₂ -CO-), wherein R is the "normal" side chain, naturally present on the carbon atom.

These modifications can occur at any of the bonds along the polypeptide chain and even at several (2-3) bonds at the same time.

Natural aromatic amino acids, Trp, Tyr and Phe, may be substituted by non-natural aromatic amino acids such as l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic), naphthylalanine, ring-methylated derivatives of Phe, halogenated derivatives of Phe or O- methyl-Tyr.

The polypeptides of some of any of the embodiments described herein may also include one or more modified amino acids or one or more non-amino acid monomers e.g. fatty acids, complex carbohydrates, etc.

The term "amino acid" is understood to include the 20 naturally occurring amino acids; those amino acids often modified post-translationally in vivo, including, for example, hydroxyproline, phosphoserine and phosphothreonine; and other unusual amino acids including, but not limited to, 2-aminoadipic acid, hydroxylysine, isodesmosine, nor-valine, nor-leucine and ornithine. Furthermore, the term "amino acid" includes both D- and L-amino acids.

Tables 2 and 3 below list naturally occurring amino acids (Table 2) and non-conventional or modified amino acids e.g. synthetic (Table 3) which can be used with some embodiments of the invention.

Table 2

Amino Acid Three-Letter Abbreviation One-letter Symbol

Alanine Ala A

Arginine Arg R

Asparagine Asn N

Aspartic acid Asp D Amino Acid Three-Letter Abbreviation One-letter Symbol

Cysteine Cys C

Glutamine Gin Q

Glutamic Acid Glu E

Glycine Gly G

Histidine His H

Isoleucine He I

Leucine Leu L

Lysine Lys K

Methionine Met M

Phenylalanine Phe F

Proline Pro P

Serine Ser S

Threonine Thr T

Tryptophan Trp w

Tyrosine Tyr Y

Valine Val V

Any amino acid as above Xaa X

Table 2 (Cont.)

Table 3

Non-conventional amino Code Non-conventional amino Code acid acid

Ornithine Orn hydroxyproline Hyp a-aminobutyric acid Abu aminonorbornyl- Norb carboxylate

D-alanine Dala aminocyclopropane- Cpro carboxylate

D-arginine Darg N-(3- Narg guanidinopropyl)glycine

D-asparagine Dasn N-(carbamylmethyl)glycine Nasn

D-aspartic acid Dasp N- (c arboxymethyl)glycine Nasp

D-cysteine Dcys N-(thiomethyl)glycine Ncys Non-conventional amino Code Non-conventional amino Code acid acid

D-glutamine Dgln N-(2-carbamylethyl)glycine Ngln

D-glutamic acid Dglu N-(2-carboxyethyl)glycine Nglu

D-histidine Dhis N-(imidazolylethyl)glycine Nhis

D-isoleucine Dile N-( 1 -methylpropyl)glycine Nile

D-leucine Dleu N-(2-methylpropyl)glycine Nleu

D-lysine Dlys N-(4-aminobutyl)glycine Nlys

D-methionine Dmet N-(2-methylthioethyl)glycine Nmet

D-ornithine Dorn N-(3-aminopropyl)glycine Norn

D-phenylalanine Dphe N-benzylglycine Nphe

D-proline Dpro N-(hydroxymethyl)glycine Nser

D- serine Dser N-( 1 -hydroxyethyl)glycine Nthr

D-threonine Dthr N-(3-indolylethyl) glycine Nhtrp

D-tryptophan Dtrp N-(/?-hydroxyphenyl)glycine Ntyr

D-tyrosine Dtyr N-( 1 -methylethyl)glycine Nval

D-valine Dval N-methylglycine Nmgly

D-N-methylalanine Dnmala L-N-methylalanine Nmala

D-N-methylarginine Dnmarg L-N-methylarginine Nmarg

D-N-methylasparagine Dnmasn L-N-methylasparagine Nmasn

D-N-methylasparatate Dnmasp L-N-methylaspartic acid Nmasp

D-N-methylcysteine Dnmcys L-N-methylcysteine Nmcys

D-N-methylglutamine Dnmgln L-N-methylglutamine Nmgln

D-N-methylglutamate Dnmglu L-N-methylglutamic acid Nmglu

D-N-methylhistidine Dnmhis L-N-methylhistidine Nmhis

D-N-methylisoleucine Dnmile L-N-methylisolleucine Nmile

D-N-methylleucine Dnmleu L-N-methylleucine Nmleu

D-N-methyllysine Dnmlys L-N-methyllysine Nmlys

D-N-methylmethionine Dnmmet L-N-methylmethionine Nmmet

D-N-methylornithine Dnmorn L-N-methylornithine Nmorn

D-N-methylphenylalanine Dnmphe L-N-methylphenylalanine Nmphe

D-N-methylproline Dnmpro L-N-methylproline Nmpro

D-N-methylserine Dnmser L-N-methylserine Nmser Non-conventional amino Code Non-conventional amino Code acid acid

D-N-methylthreonine Dnmthr L-N-methylthreonine Nmthr

D-N-methyltryptophan Dnmtrp L-N-methyltryptophan Nmtrp

D-N-methyltyrosine Dnmtyr L-N-methyltyrosine Nmtyr

D-N-methylvaline Dnmval L-N-methylvaline Nmval

L-norleucine Nle L-N-methylnorleucine Nmnle

L-norv aline Nva L-N-methylnorv aline Nmnva

L-ethylglycine Etg L-N-methyl-ethylglycine Nmetg

L-t-butylglycine Tbug L-N-methyl-t-butylglycine Nmtbug

L-homophenylalanine Hphe L-N-methyl- Nmhphe homophenylalanine

a-naphthylalanine Anap N-methyl-a-naphthylalanine Nmanap

Penicillamine Pen N-methylpenicillamine Nmpen γ-aminobutyric acid Gabu N-methyl-y-aminobutyrate Nmgabu cyclohexylalanine Chexa N-methyl-cyclohexylalanine Nmchexa cyclopentylalanine Cpen N-methyl-cyclopentylalanine Nmcpen a-amino-a-methylbutyrate Aabu N-methyl-a-amino-a- Nmaabu methylbutyrate

a-aminoisobutyric acid Aib N-methyl-a- Nmaib aminoisobutyrate

D-a-methylarginine Dmarg L- a-methylarginine Marg

D-a-methylasparagine Dmasn L-a-methylasparagine Masn

D-a-methylaspartate Dmasp L-a-methylaspartate Masp

D-a-methylcysteine Dmcys L-a-methylcysteine Mcys

D-a-methylglutamine Dmgln L- a-methylglutamine Mgln

D-a-methyl glutamic acid Dmglu L- a-methylglutamate Mglu

D-a-methylhistidine Dmhis L-a-methylhistidine Mhis

D-a-methylisoleucine Dmile L-a-methylisoleucine Mile

D-a-methylleucine Dmleu L- a-methylleucine Mleu

D-a-methyllysine Dmlys L-a-methyllysine Mlys

D-a-methylmethionine Dmmet L- a-methylmethionine Mmet Non-conventional amino Code Non-conventional amino Code acid acid

D-a-methylornithine Dmorn L- a-methylornithine Morn

D-a-methylphenylalanine Dmphe L- a-methylphenylalanine Mphe

D-a-methylproline Dmpro L- a-methylproline Mpro

D-a-methylserine Dmser L-a-methylserine Mser

D-a-methylthreonine Dmthr L- a-methylthreonine Mthr

D-a-methyltryptophan Dmtrp L- a-methyltryptophan Mtrp

D-a-methyltyrosine Dmtyr L- a-methyltyro sine Mtyr

D-a-methylvaline Dmval L-a-methylvaline Mval

N-cyclobutylglycine Ncbut L-a-methylnorv aline Mnva

N-cycloheptylglycine Nchep L- a-methylethylglycine Metg

N-cyclohexylglycine Nchex L- a-methyl- i-butylglycine Mtbug

N-cyclodecylglycine Ncdec L-a-methyl- Mhphe homophenylalanine

N-cyclododecylglycine Ncdod a-methyl-a-naphthylalanine Manap

N-cyclooctylglycine Ncoct a-methylpenicillamine Mpen

N-cyclopropylglycine Ncpro a-methyl-y-aminobutyrate Mgabu

N-cycloundecylglycine Ncund a-methyl-cyclohexylalanine Mchexa

N- (2- aminoethyl)glycine Naeg a-methyl-cyclopentylalanine Mcpen

N-(2,2- Nbhm N-(N-(2,2-diphenylethyl) Nnbhm diphenylethyl)glycine carbamylmethyl-glycine

N-(3,3- Nbhe N-(N-(3,3-diphenylpropyl) Nnbhe diphenylpropyl)glycine carbamylmethyl-glycine

1 -carboxy- 1 -(2,2-diphenyl Nmbc 1,2,3,4- Tic ethylamino)cyclopropane tetrahydroisoquinoline-3- carboxylic acid

Phospho serine pSer pho spho threonine pThr phospho tyro sine pTyr O-methyl-tyrosine

2-aminoadipic acid hydroxylysine

Table 3 ( Cont.) The polypeptides of some embodiments of the invention are preferably utilized in a linear form, although it will be appreciated that in cases where cyclization does not severely interfere with polypeptide characteristics, cyclic forms of the polypeptide can also be utilized.

The polypeptides of some embodiments of the invention may be synthesized by any techniques that are known to those skilled in the art of peptide synthesis. For solid phase peptide synthesis, a summary of the many techniques may be found in J. M. Stewart and J. D. Young, Solid Phase Peptide Synthesis, W. H. Freeman Co. (San Francisco), 1963 and J. Meienhofer, Hormonal Proteins and Peptides, vol. 2, p. 46, Academic Press (New York), 1973. For classical solution synthesis see G. Schroder and K. Lupke, The Peptides, vol. 1, Academic Press (New York), 1965.

In general, these methods comprise the sequential addition of one or more amino acids or suitably protected amino acids to a growing polypeptide chain. Normally, either the amino or carboxyl group of the first amino acid is protected by a suitable protecting group. The protected or derivatized amino acid can then either be attached to an inert solid support or utilized in solution by adding the next amino acid in the sequence having the complimentary (amino or carboxyl) group suitably protected, under conditions suitable for forming the amide linkage. The protecting group is then removed from this newly added amino acid residue and the next amino acid (suitably protected) is then added, and so forth. After all the desired amino acids have been linked in the proper sequence, any remaining protecting groups (and any solid support) are removed sequentially or concurrently, to afford the final polypeptide compound. By simple modification of this general procedure, it is possible to add more than one amino acid at a time to a growing chain, for example, by coupling (under conditions which do not racemize chiral centers) a protected tripeptide with a properly protected dipeptide to form, after de-protection, a pentapeptide and so forth. Further description of polypeptide synthesis is disclosed in U.S. Patent No. 6,472,505.

A preferred method of preparing a polypeptide some embodiments of the invention involves solid phase polypeptide synthesis.

Large scale polypeptide synthesis is described by Andersson [Biopolymers 2000; 55(3):227-50].

Polynucleotides of the present invention may be prepared using PCR techniques as described in the Examples section below, or can be chemically synthesized or by any other method or procedure known in the art for ligation of two different DNA sequences. See, for example, "Current Protocols in Molecular Biology", eds. Ausubel et al., John Wiley & Sons, 1992. Polypeptides of the present invention can be purified using a variety of standard protein purification techniques, such as, but not limited to, heat treatments, salting out for example with ammonium sulfate, polyethyleneimines (PEI) precipitation, affinity chromatography, ion exchange chromatography, filtration, electrophoresis, hydrophobic interaction chromatography, gel filtration chromatography, reverse phase chromatography, concanavalin A chromatography, chromatofocusing and differential solubilization.

To facilitate recovery, the expressed coding sequence can be engineered to encode the polypeptide of the present invention and fused cleavable moiety e.g. histidine. Such a fusion protein can be designed so that the polypeptide can be readily isolated by affinity chromatography; e.g., by immobilization on a column specific for the cleavable moiety (see Examples section, herein below).

Where a cleavage site is engineered between the polypeptide and the cleavable moiety, the polypeptide can be released from the chromatographic column by treatment with an appropriate enzyme or agent that specifically cleaves the fusion protein at this site [e.g., see Booth et al, Immunol. Lett. 19:65-70 (1988); and Gardella et al, J. Biol. Chem. 265: 15854- 15859 (1990)].

The polypeptide of the present invention is preferably retrieved in a "substantially pure" form.

As used herein, the phrase "substantially pure" refers to a purity that allows for the effective use of the protein in the applications described herein.

In addition to being synthesizable in host cells, the polypeptide of the present invention can also be synthesized using in vitro expression systems. These methods are well known in the art and the components of the system are commercially available.

Color and optical effects:

The treatment of hair using CNC describes herein may optionally be in combination with coloring agents and other agents for altering the appearance of hair.

Typically, many pigments and dyes are not particularly suitable for coloring hair, as they do not adhere to the hair for long.

Without being bound by any particular theory, it is believed that a layer of applied CNC (especially cross-linked CNC) on the hair surface, according to embodiments described herein, can embed pigments (e.g., organic pigments) and other agents with desired optical properties, thereby providing the hair (in a controllable manner) with a desired absorption (e.g., color and/or UV protection) and/or shine features. Such agents may be colorless or colored mineral and/or organic pigments. Examples of suitable mineral pigments include, without limitation, titanium dioxide (used as a white pigment), cerium oxide, zinc oxide, iron oxide (black, yellow and red), chromium oxide, manganese violet, ultramarine blue, chromium hydrate and ferric blue. In addition, metal powders such as aluminum or copper and their mixtures can optionally be utilized.

Examples of suitable organic pigments (which may be lipophilic and/or water-soluble) include, without limitation, carbon black, D & C types and such pigments based on cochineal carmine or barium, strontium, calcium, aluminum and their mixtures; nacre or nacreous pigments; lipophilic dyes such as soybean oil, Sudan brown, DC Yellow 11, DC Orange 5, quinoline yellow, and Sudan Red III; water-soluble dyes such as plant extracts (e.g., Aleurites moluccana Willd, Alkanna tinctoria Tausch, Areca catechu L., Arrabidaea chica E.), optionally in a lyophilized, paste or solution form.

Nanoparticles may optionally be used (e.g., embedded in the CNC), for example, Ti0 ₂ , Si0 ₂ (e.g., spherical shaped Si0 ₂ ), ZnO nanoparticles, gold nano particles, and/or core-shell nanoparticles. The nanoparticles are optionally selected to provide UV resistance and/or shine to the hair.

The nanoparticles may optionally comprise fluorescence quantum dots (e.g., as a colloid), for example, lead sulfide, lead selenide, cadmium selenide, and/or cadmium sulfide quantum dots.

Quantum dots are optionally covalently bound to the CNC, according to any of the embodiments described herein relating to covalent modification of CNC.

Quantum dots are semiconductor nanocrystals that exhibit unique optical properties, including color. As known in the art, the color properties of quantum dots are affected both by the chemical composition and the size of the quantum dots. For example, smaller dots emit bluer (higher energy) light.

Compositions:

The cellulose nanocrystals and/or resilin according to any of the embodiments presented herein can be utilized either per se, or, preferably, as a part of a composition comprising a suitable carrier.

According to an aspect of embodiments of the invention, there is provided a hair- straightening composition comprising modified and/or non-modified cellulose nanocrystals (according to any of the respective embodiments described herein), and a carrier suitable for application to hair. According to an aspect of embodiments of the invention, there is provided a hair- straightening composition comprising resilin (according to any of the respective embodiments described herein), and a carrier suitable for application to hair. In some such embodiments, the hair-straightening composition is identified as being for use in maintenance of straightened hair following a hair-straightening treatment (e.g., a treatment according to any of the respective embodiments described herein), for example, in addition to, or rather than, being for use in a hair-straightening treatment per se. In some embodiments, the hair- straightening treatment comprises applying cellulose nanocrystals (e.g., according to any of the respective embodiments described herein).

Herein, the phrase "carrier suitable for application to hair" refers to a carrier or a diluent that does not cause significant irritation or cosmetically deleterious effects to an organism and does not abrogate the biological and/or cosmetic activity and properties of the administered agent.

Herein, the phrase "hair- straightening composition" encompasses any composition useful in a method of obtaining straighter hair, and is not intended to imply that the composition by itself is suitable for straightening hair. For example, as discussed herein, methods of straightening hair commonly utilize more than one composition, as well as physical processes such as applying heat and pressure.

The carrier may optionally comprise one or more excipients, that is, inert substance(s) added to a composition to further facilitate administration of a compound and/or processing of ingredients into preparations suitable for administration (e.g., onto hair). Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives (e.g., other than cellulose nanocrystals), gelatin, vegetable oils, and polymers such as polyethylene glycols.

Techniques for formulation and administration of active agents may be found in

"Remington's Pharmaceutical Sciences" Mack Publishing Co., Easton, PA, latest edition, which is incorporated herein by reference.

By selecting the appropriate carrier and optionally other ingredients that can be included in the composition, as is detailed herein, the hair-straightening compositions described herein may be formulated into any form typically employed for topical application such as application to hair. Hence, the hair- straightening compositions can be, for example, in a form of a cream, an ointment, a paste, a gel, a lotion, a milk, a suspension, an aerosol, a spray, a foam, a shampoo, a hair conditioner, a swab, a pledget, a pad, and a soap. Ointments are semisolid preparations, typically based on vegetable oil (e.g. shea butter and/or cocoa butter), petrolatum or petroleum derivatives. The specific ointment base to be used is one that provides for optimum delivery for the hair-straightening agent chosen for a given formulation (e.g., cellulose nanocrystals and/or resilin), and, preferably, provides for other desired characteristics as well (e.g., emolliency). As with other carriers or vehicles, an ointment base should be inert, stable, nonirritating and nonsensitizing.

Lotions are preparations that may to be applied to the hair without friction. Lotions are typically liquid or semiliquid preparations in which solid particles, including the hair- straightening agent, are present in a water or alcohol base. Lotions are typically preferred for treating large areas, due to the ease of applying a more fluid composition. Lotions are typically suspensions of solids, and oftentimes comprise a liquid oily emulsion of the oil-in-water type. It is generally necessary that the insoluble matter in a lotion be finely divided. Lotions typically contain suspending agents to produce better dispersions as well as compounds useful for localizing and holding the hair-straightening agent in contact with the hair.

Creams are viscous liquids or semisolid emulsions, either oil-in-water or water-in-oil. Cream bases typically contain an oil phase, an emulsifier and an aqueous phase. The oil phase, also called the "internal" phase, is generally comprised of petrolatum and/or a fatty alcohol such as cetyl or stearyl alcohol. The aqueous phase typically, although not necessarily, exceeds the oil phase in volume, and generally contains a humectant. The emulsifier in a cream formulation is generally a nonionic, anionic, cationic or amphoteric surfactant.

Pastes are semisolid dosage forms in which the hair-straightening agent is suspended in a suitable base. Depending on the nature of the base, pastes are divided between fatty pastes or those made from a single-phase aqueous gels. The base in a fatty paste is generally petrolatum, hydrophilic petrolatum and the like. The pastes made from single-phase aqueous gels generally incorporate carboxymethylcellulose or the like as a base.

Gel formulations are semisolid, suspension-type systems. Single-phase gels contain organic macromolecules distributed substantially uniformly throughout the carrier liquid, which is typically aqueous, but also, preferably, contains a non-aqueous solvent and, optionally, an oil. Preferred organic macromolecules, i.e., gelling agents, are crosslinked acrylic acid polymers such as the family of carbomer polymers, e.g., carboxypolyalkylenes that may be obtained commercially under the trademark CARBOPOL™. Other types of preferred polymers in this context are hydrophilic polymers such as polyethylene oxides, polyoxyethylene- polyoxypropylene copolymers and polyvinylalcohol; cellulosic polymers such as hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose phthalate, and methyl cellulose; gums such as tragacanth and xanthan gum; sodium alginate; and gelatin. In order to prepare a uniform gel, dispersing agents such as alcohol or glycerin can be added, or the gelling agent can be dispersed by trituration, mechanical mixing or stirring, or combinations thereof.

Sprays generally provide the hair-straightening agent (e.g., cellulose nanocrystals and/or resilin) in an aqueous and/or volatile solvent solution which can be misted onto the hair for delivery. Such sprays include those formulated to provide for concentration of the hair- straightening agent solution at the site of administration following delivery, e.g., the spray solution can be primarily composed of a volatile liquid in which the hair-straightening agent can be dissolved. Upon delivery to the hair, the carrier evaporates, leaving concentrated hair- straightening agent at the site of administration.

Foam compositions are typically formulated in a single or multiple phase liquid form and housed in a suitable container, optionally together with a propellant which facilitates the expulsion of the composition from the container, thus transforming it into foam upon application. Other foam forming techniques include, for example the "Bag-in-a-can" formulation technique. Compositions thus formulated typically contain a low-boiling hydrocarbon, e.g., isopropane. Application and agitation of such a composition at the body temperature cause the isopropane to vaporize and generate the foam, in a manner similar to a pressurized aerosol foaming system. Foams can be water-based or hydro alcoholic, but are typically formulated with high volatile solvent content which, upon application to the hair of a user, quickly evaporates, leaving concentrated hair- straightening agent on the hair.

Representative examples of suitable carriers according to embodiments of the present invention therefore include, without limitation, water, liquid alcohols (optionally ethanol), liquid glycols, liquid polyalkylene glycols, liquid esters, liquid amides, liquid protein hydrolysates, liquid alkylated protein hydrolysates, liquid lanolin and lanolin derivatives, and like materials commonly employed in cosmetic compositions.

The chemical composition of the carrier is typically selected according to the desired form of the hair- straightening composition. Further, the chemical composition of the carrier is selected so as to suit the desired purpose of the hair-straightening composition. For example, a composition for maintenance by repeated application (according to any of the respective embodiments described herein) may be selected to be milder (e.g., less irritating upon repeated application) and/or more convenient for use (e.g., home use) than a hair- straightening composition utilized in a single treatment (e.g., a treatment performed by a hairstyling professional). In addition, a hair- straightening composition utilized in a treatment comprising heat and pressure (according to any of the respective embodiments described herein) may be selected to be compatible with such conditions, whereas a composition for maintenance (according to any of the respective embodiments described herein) may not need to be compatible with such conditions. In addition, resilin may be sensitive to certain solvents to which celulose nanocrystals are resistant, and vice versa.

The carrier is optionally selected such that the composition is quick-drying, facilitating the spreading of the composition through the hair but minimizing dripping out of the hair and/or onto the scalp; non-harmful; and does not cause the hair to have an unappealing feel, appearance or aroma.

For example, dripping may be prevented by using a viscous carrier (e.g. cream, gel, foam), which is fluid enough to facilitate spreading through the hair, but sufficiently viscous so as to avoid dripping, as well as by using a quick-drying spray carrier, in which the carrier is sprayed onto the desired location, and then dries up before dripping out of the desired location.

Reflective compounds, such as silicone oils (e.g., disiloxane, dimethicone, and cyclomethicone), may be included in a carrier to provide hair with a glossy appearance.

Compositions of the present invention may, if desired, be presented (e.g., packaged) in a pack or dispenser device, such as an FDA (the U.S. Food and Drug Administration) approved kit, which may contain one or more compositions described herein. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of cosmetics and/or pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions for human or veterinary administration. Such notice, for example, may be of labeling approved by the U.S. Food and Drug Administration. Compositions comprising cellulose nanocrystals and/or resilin (according to any of the respective embodiments described herein) may also be prepared, placed in an appropriate container (individually and/or together in a kit), and labeled for treatment of hair (e.g., according to any of the embodiments described herein).

In some of any of the embodiments described herein, a concentration of modified and/or non-modified CNC in a composition comprising same (e.g., a packaged composition) ranges from about 0.1 % to about 5 %, by weight, including any intermediate values and subranges therebetween. It is to be noted that higher concentrations are also contemplated and that such compositions may be diluted before application. In some of any of the embodiments described herein, a concentration of a resilin in a composition (e.g., a packaged composition) comprising same ranges from about 0.1 mg/ml to about 200 mg/ml, including any intermediate values and subranges therebetween. It is to be noted that higher concentrations are also contemplated and that such compositions may be diluted before application.

According to some embodiments of the present invention, one or more of the other agents utilized in any of the methods described herein forms a part of a composition which further comprises a suitable carrier, as described herein for CNC and resilin. Such compositions are well known to those skilled in the art.

In some of any of the embodiments described herein, a concentration of a reducing agent in a composition (e.g., a packaged composition) comprising same ranges from about 1 mM to 2M, including any intermediate values and subranges therebetween. It is to be noted that higher concentrations are also contemplated and that such compositions may be diluted before application.

In some of any of the embodiments described herein, a concentration of a cationic agent in a composition (e.g., a packaged composition) comprising same ranges from about 0.1 % to about 40 %, by weight, including any intermediate values and subranges therebetween. It is to be noted that higher concentrations are also contemplated and that such compositions may be diluted before application.

In some of any of the embodiments described herein, a concentration of a cross-linking agent in a composition (e.g., a packaged composition) comprising same ranges from about 1 mg/ml to about 20 mg/ml, by weight, including any intermediate values and subranges therebetween. It is to be noted that higher concentrations are also contemplated and that such compositions may be diluted before application.

According to an aspect of some embodiments of the invention, there is provided a kit for straightening hair, the kit comprising, as separate containers:

at least one container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein), or a composition comprising same; and

at least one additional container comprising at least one additional composition for use in combination with cellulose nanocrystals (e.g., according to any of the respective embodiments described herein.

The additional container(s) may comprise, for example, a pre-treatment composition comprising at least one cationic agent (according to any of the respective embodiments described herein); and/or a composition comprising resilin (according to any of the respective embodiments described herein), e.g., optionally a composition for maintenance of straightened hair and/or at least one agent capable of cleaving disulfide bonds in hair according to any of the respective embodiments described herein.

In exemplary embodiments, the kit comprises:

a first container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein), or a composition comprising same; and

a second container comprising a pre-treatment composition comprising at least one cationic agent (according to any of the respective embodiments described herein).

In exemplary embodiments, the kit comprises:

a first container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein);

a second container comprising a pre-treatment composition comprising at least one cationic agent (according to any of the respective embodiments described herein); and

a third container a composition comprising resilin (according to any of the respective embodiments described herein).

In exemplary embodiments, the kit comprises:

a first container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein), or a composition comprising same; and

a second container a composition comprising resilin (according to any of the respective embodiments described herein).

In exemplary embodiments, the kit comprises:

a first container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein), or a composition comprising same;

a second container comprising a pre-treatment composition comprising at least one cationic agent (according to any of the respective embodiments described herein); and

a third container a composition comprising a composition for maintenance of straightened hair.

In exemplary embodiments, the kit comprises: a first container comprising cellulose nanocrystals or chemically modified cellulose nanocrystals (according to any of the respective embodiments described herein), or a composition comprising same; and

a second container comprising a composition for maintenance of straightened hair.

In some of any of the above-described exemplary embodiments for a kit, the kit may further comprise an additional container comprising at least one agent capable of cleaving disulfide bonds in hair, as described herein in any of the respective embodiments, or a composition comprising same.

In some of any of the above-described exemplary embodiments for a kit, the kit may further comprise an additional container comprising a cross-linking agent, as described herein in any of the respective embodiments, or a composition comprising same.

In any of the kits described herein, the concentration of the agent (reducing agent, cationic agent, CNC, resilin, and any modifications and combinations thereof) can be a final concentration for use in the intended application, or a higher concentration which is diluted prior to application. In some embodiments, the kit may further comprise one or more suitable carriers for diluting the agents, and optionally means for performing the dilution, for example, a receptacle with measuring units, means to mix the diluted composition, and the like.

In some embodiments, any of the kits described herein further comprises instructions how to use the agents or compositions included therein, and in some embodiments, such instructions are in accordance with any of the respective methods described herein. The instructions may further include diluting one or more of the agents/compositions and instructions with a suitable carrier how to perform the dilution. The instructions may further include mixing one or more of the agents/compositions before application and instructions how to perform the mixing.

In some embodiments, the kit may further comprise means for mixing one or more of the agents/compositions before application.

In some of the any of the embodiments described herein for a kit, one or more of the containers in the kit is configured for dispensing a composition directly to the hair. For example, a container can be configured for dispensing a composition by means of a spray or a foam, or be a squeeze-bottle which dispenses the composition via a nozzle. Any other means for dispensing the composition are contemplated, depending on the composition.

In some of the any of the embodiments described herein for a kit, the kit, or one or more of the containers therein, may further include means for applying the composition to the hair, for example, a dedicated brush, sponge, gauze, pledget, etc. The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to".

The term "consisting of means "including and limited to".

The term "consisting essentially of means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.

The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". Any particular embodiment of the invention may include a plurality of "optional" features unless such features conflict.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

As used herein the term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, cosmetic, pharmacological, biological, biochemical and medical arts.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non-limiting fashion.

Material:

Arginine was obtained from Sigma-Aldrich.

BTMS (behentrimonium methosulfate) was obtained from Roga Cosmetics.

Cetrimonium chloride was obtained from Emilia Cosmetics.

Chitosan was obtained from Sigma-Aldrich.

CNC (cellulose nanocrystals) was obtained from Melodea Ltd.

Cysteine was obtained from Sigma-Aldrich.

Gelatin was obtained from was obtained from Sigma-Aldrich.

Hydro-keratin was obtained from Helion Ltd.

MES (2-(N-morpholino)ethanesulfonic acid) was obtained from Sigma-Aldrich.

Polylysine was obtained from Sigma-Aldrich.

SDS (sodium dodecyl sulfate) was obtained from Bio-Lab Ltd.

SHP (sodium hypophosphite) was obtained from Sigma-Aldrich.

SLS-free shampoo was obtained from Mommy Care Ltd.

SMBS (sodium metabisulfite) was obtained from Sigma-Aldrich.

Resilin production:

Resilin with a fused cellulose binding domain (RES-CBD) was prepared according to procedures similar to those described in International Patent Application Publication WO 2015/068160, Qin et al. [Biomacromolecules 2009, 10:3227-3234], International Patent Application Publication WO 2009/069123, and Qin et al. [Biomaterials 2011, 32:9231-9243].

Recombinant resilin was produced as a histidine-tagged (6H) chimeric protein composed of D. melanogaster resilin exon 1 (17 elastic repeats) fused to an N-terminal histidine tag, and to C. cellulovorans cellulose binding domain (CBD).

The 6H-res-CBD gene was cloned into a pHis-parallel3 expression vector, which confers ampicillin resistance upon its host. A lysogeny broth-agar plate containing ampicillin was streaked with a glycerol stock of E.coli bacteria strain BL-21(DE3) star (Invitrogen Carlsbad, CA) containing the expression vector pHis-parallel3 _6H-17res-CBD, and incubated overnight (ON) at 37 °C. A single colony was used for the inoculation of 200 ml M9 minimal media containing glucose (0.8 % w/v) and ampicillin (100 mg/liter). The culture was grown in a rotary shaker (12 h, 250 rpm, 35 °C) until an optical density at 600 nm (OD 600 nm) of ~3. Next, bacteria culture (2 % v/v) was used to inoculate a bench fermentor (New Brunswick Scientific, Edison, NJ, USA) containing 10 liters of TB, glucose (0.8 % w/v), ampicillin (100 mg/liter), and antifoam "B" emulsion (4 ml of 1:3 diluted stock). The fermentor was operated at 400 rpm and 35 °C, with an air flow rate of 5 vvm and air pressure of 10 psi. Protein expression was induced at OD 600nm ~ 8 (the mid-log phase) by the addition of isopropyl b-D-1- thiogalactopyranoside (IPTG), at a final concentration of 0.5 mM. Anti-foaming agent was added in small doses (1 ml) whenever necessary. Finally, 4 hour post-induction (OD 600nm -18), bacteria were harvested by centrifugation (10,000 rpm, 4 °C) and stored at -80 °C until further use. Total bacterial samples (pre- and post-IPTG induction) were collected and analyzed by SDS-PAGE (12 %) and western blot analysis.

Bacterial pellets were thawed at 4 °C and homogenized in a lysis buffer containing sodium phosphate (25 mM, pH 7.5) and NaCl (150 mM). Next, the homogenized bacteria were sonicated (80 % amplitude, 50 % pulse time, 40 minutes; 500 V UTPlOOOhd industrial sonicator (Hielscher, Germany)) on ice, and the soluble fraction was separated by centrifugation (11,000 rpm, 30 minutes, 20 °C). The soluble fraction was removed, and the pellet containing the 6H-res- CBD in the form of inclusion bodies (IBs) was washed once with sodium phosphate (25 mM, pH 7.5), NaCl (150 mM) and Triton X-100 (0.8 wt%) buffer followed by one additional washing step using a sodium phosphate (25 mM, pH 7.5) and NaCl (150 mM) detergent-free buffer. The IBs containing 6H-res-CBD were then dissolved in sodium phosphate (20 mM, pH 11.8) and the soluble fraction was collected (and diluted to ~2 mg/ml using the same buffer) for protein refolding. Refolding of the protein was carried out via a drop-wise addition of 1M HC1 until reaching a pH of 8-9. Cellulose nanocrystal modification:

Aldehyde-CNC (CNC modified to comprise surface aldehyde groups) was prepared as follow: The pH of a 2 % CNC suspension was adjusted to a range of 2.5-3. 2 of grams NaI0 ₄ (sodium periodate) were dissolved in 100 ml of the 2 % CNC suspension (1: 1 weight ratio), and the suspension was stirred for 24 hours at room temperature, so as to convert glucose residues in cellulose to dialdehyde residues by oxidative cleavage. About 10 ml of ethylene glycol was then added in order to stop the reaction. The suspension was dialyzed against distilled water for about 3 days, thereby obtaining aldehyde-CNC.

In all of the Examples below, and unless otherwise indicated, whenever a modified or non-modified CNC is employed, it is employed either per se or in combination with a cross- linking agent as described herein.

Scanning Electron Microscopy (SEM) measurements:

SEM images were obtained by A Jeol JSM 5410 Scanning Electron microscope, samples preparation was performed using Polaron SEM Coating Unit.

EXAMPLE 1

Effect of cellulose nanocrystals on hair undergoing straightening treatment

Healthy curly hair samples were subjected to following hair care treatments for hair straightening, in order to assess the effect of cellulose nanocrystals (CNC). Following treatments (and for some samples, repeated washes subsequent to treatment), the hair was analyzed visually and using scanning electron microscopy (SEM).

Sample 1-1 - Control sample (untreated), followed by repeated washes: Natural curly hair was washed with soapless soap. Treated hair samples were then washed with water 19 times, once per day. 28 days from the beginning of treatment, the samples were washed with regular shampoo 6 times, and then analyzed using SEM.

Sample 1-2 - 5 mM SMBS + 0.01 % poly-Lys + CNC, followed by repeated washes: Natural curly hair was washed with water and soapless soap and partially air dried. 5 mM of sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples) and left for 15 minutes. Hair samples were then fan-dried and straightened with a hot iron. SMBS was again spread on the hair and left for 15 minutes. The hair was washed with water, fan-dried and straightened with a hot iron. 0.01 % polylysine (poly-Lys) was spread onto the hair and air- dried. The hair was washed with water and fan-dried. CNC was spread onto the hair, which was air-dried and straightened very slowly for 5-6 minutes with a hot iron. The hair was washed with water, fan-dried, washed again with water and air-dried. Treated hair samples were then washed with water 19 times, once per day. 28 days from the beginning of treatment, the samples were washed with regular shampoo 6 times, and then analyzed using SEM.

Sample 1-3 - 0.5 % SDS + 1 % NaCl + 5 mM SMBS + 0.5 M cysteine + 2 % cetrimonium chloride: Natural curly hair was washed with shampoo and conditioner and air- dried. Hair samples were washed again with 0.5 % sodium dodecyl sulfate (SDS) and 1 % NaCl, and then, 5 mM sodium metabisulfite was applied on the hair (spread on the hair samples using a lice comb) and left for 10 minutes. The hair was then fan-dried and straightened with a hot iron. 0.5 M cysteine was added (spread on the hair samples using a lice comb) and left for 10 minutes. 2 % cetrimonium chloride was added (spread on the hair samples using a lice comb), and the hair was partially air-dried for 30 minutes, fan-dried and straightened with a hot iron. Hair was washed with water and air-dried.

Sample 1-4 - 0.5 % SDS + 1 % NaCl: Natural curly hair was washed with shampoo and conditioner and then air-dried. Hair samples were washed again with 0.5 % SDS and 1 % NaCl and air-dried.

Sample 1-5 - 0.5 % SDS + 1 % NaCl + 5 mM SMBS + 0.5 M cysteine + 2 % cetrimonium chloride + CNC: Natural curly hair was washed with shampoo and conditioner and air-dried. Hair samples were washed again with 0.5 % SDS and 1 % NaCl, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples using a lice comb) and left for 10 minutes. The hair was then fan-dried and straightened with a hot iron. 0.5 M cysteine was added (spread on the hair samples using a lice comb) and left for 10 minutes. 2 % cetrimonium chloride was added (spread on the hair samples using a lice comb), and the hair was partially air dried for 30 minutes, fan-dried and straightened with a hot iron. Hair was washed with water, and CNC was spread onto the hair with a lice comb. The hair was partially air-dried for 30 minutes and fan-dried. The hair was then straightened slowly for 2 minutes with a hot iron (with the help of a lice comb). The hair was then washed with water and air-dried.

As shown in FIGs. 1-3, the use of CNC in combination with a disulfide -reducing agent (SMBS and/or cysteine) in hair treatment (e.g., Sample 1-5) was associated with a greater degree of hair straightening than obtained for hair treatment with disulfide-reducing agent without CNC (e.g., Sample 1-3), as well as in the presence of a layer coating the hair surface after treatment (observable by electron microscopy). As further shown therein, the effect of treatment with CNC was weaker following repeated washing of the hair (e.g., Sample 1-2).

These results indicate that application of CNC enhances hair straightening, and suggests that the effect of CNC is associated with formation of a layer coating the hair surface. Healthy curly hair samples were further subjected to various hair care treatments for hair straightening (involving 5 mM sodium metabisulfite), in order to assess the long-term effect of cellulose nanocrystals (CNC). Following treatments, hair samples were washed with water 9 or 19 times, once per day, and then washed with regular shampoo 8 times (on 8 different days).

Sample 2-1 - 5 mM SMBS + 200 mM cysteine + 2 % chitosan + CNC: Natural curly hair was washed with water and soapless soap and air-dried. Hair samples were straightened using hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples). 200 mM cysteine was added immediately, and the hair was partially air-dried for 15 minutes and fan-dried. The hair was washed with water, fan-dried and straightened with a hot iron. 2 % chitosan was spread onto the hair with a lice comb, and the hair was air-dried for 1 hour and then fan-dried. The hair was washed with water, fan-dried and straightened with a hot iron. CNC was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes and fan-dried. The hair was straightened very slowly for 6 minutes with a hot iron (with the help of a lice comb), washed with water and air-dried. The hair sample was washed with water 9 times, then washed with regular shampoo on days 15, 16, 19, 20, 21, 24, 25 and 26, and analyzed on day 27.

Sample 2-2 - 5 mM SMBS + 200 mM cysteine: Natural curly hair was washed with water and soapless soap and air-dried. Hair samples were straightened with a hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples). 200mM cysteine was added immediately and the hair was partially air-dried for 15 minutes. The sample was fan dried and washed with water, and then again fan-dried, straightened with a hot iron, washed with water and air-dried. The hair sample was washed with water 9 times, then washed with regular shampoo on days 15, 16, 19, 20, 21, 24, 25 and 26, and analyzed on day 27.

Sample 2-3 - 5 mM SMBS + 2 % chitosan (new, prepared in 5 % vinegar + 0.2 M NaCl) + CNC: Natural curly hair was washed with water and soapless soap and air-dried. The hair sample was straightened using a hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples). SMBS was left on the hair for 15 minutes, and the hair was then fan-dried and straightened with a hot iron. 2 % chitosan was spread onto the hair with a lice comb, and the hair was partially air-dried for 1 hour, fan-dried and washed with water. The hair was then again fan-dried and straightened with a hot iron. CNC was spread onto the hair with a lice comb, and the hair was partially air dried for 30 minutes and fan-dried. The hair sample was straightened very slowly for 6 minutes with a hot iron (with the help of a lice comb), then washed with water and air-dried. The hair sample was washed with water 9 times, then washed with regular shampoo on days 15, 16, 19, 20, 21, 24, 25 and 26, and analyzed on day 27.

Sample 2-4 - 5 mM SMBS + 2 % chitosan: Natural curly hair was washed with water and soapless soap and air-dried. 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples) and left for 15 minutes. The hair was fan-dried and straightened with a hot iron. SMBS was again spread on the hair and left for 15 minutes. The hair was washed with water, fan-dried and straightened with a hot iron. 2 % chitosan was spread onto the hair, which was then partially air-dried for 1 hour and fan-dried. The hair was washed with water and air-dried. The hair sample was washed with water 19 times, then washed with regular shampoo on days 24, 25, 29, 30, 31, 34, 35 and 36, and analyzed on day 37.

Sample 2-5 - 5 mM SMBS + 2 % chitosan + CNC: Natural curly hair was washed with water and soapless soap and air-dried. 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples) and left for 15 minutes. The hair was fan-dried and straightened with a hot iron. SMBS was again spread on the hair and left for 15 minutes. The hair was washed with water, fan-dried and straightened with a hot iron. 2 % chitosan was spread onto the hair, which was then partially air-dried for 1 hour and fan-dried. The hair was washed with water and fan-dried. CNC was spread onto the hair, which was then partially air-dried for 30 minutes and fan-dried. The hair was straightened very slowly for 6 minutes with a hot iron, and then washed with water, fan-dried, washed again with water and air-dried. The hair sample was washed with water 19 times, then washed with regular shampoo on days 24, 25, 29, 30, 31, 34, 35 and 36, and analyzed on day 37.

As shown in FIGs. 4-6, the use of CNC in combination with SMBS and/or cysteine in hair treatment (Samples 2-1, 2-3 and 2-5) was associated with a greater degree of hair straightening than obtained upon corresponding hair treatment with SMBS without CNC (Samples 2-2 and 2-4), as well as in the presence of a layer coating the hair surface after treatment (observable by electron microscopy). As further shown therein, the effect of treatment with CNC was maintained over the course of several weeks with repeated washings.

These results indicate that application of CNC enhances the permanence of hair straightening.

Healthy curly hair samples were further subjected to various hair care treatments for hair straightening (involving 5 mM sodium metabisulfite), followed by a regimen of regular washing, in order to further assess the long-term effect of cellulose nanocrystals (CNC).

Sample 3-1 - 5 mM SMBS + aldehyde-CNC: Natural curly hair was washed with water and soapless soap and air-dried. Hair samples were straightened using a hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair samples) and left for 15 minutes, and the hair was then fan-dried and straightened with a hot iron. Aldehyde-CNC (prepared as described hereinabove) was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes and fan-dried. The hair was straightened using a hot iron (with the help of a lice comb), washed with water and air-dried. The hair sample was washed with water 9 times (once a day), and then washed with regular shampoo on days 15, 16, 19, 20, 21, 24, 25 and 26, and analyzed on day 27.

Sample 3-2 - 5 mM SMBS + 0.5 M Cys + 2 % gelatin: Natural curly hair was washed with shampoo and conditioner and then fan-dried. The hair sample was straightened using a hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread on the hair sample) and 0.5 M cysteine was added and left for 15 minutes. The hair was then fan-dried, straightened with a hot iron and washed with water, and again fan-dried and straightened with a hot iron. 0.5 M cysteine was added again, and 2 % gelatin was spread onto the hair with a lice comb; and the hair was air-dried for 30 minutes and fan-dried, and then washed with water and air-dried. The hair sample was washed with water 10 times, on days 1, 2, 3, 4, 7, 8, 9, 12, 13 and 14, and analyzed on day 15.

Sample 3-3 - 5 mM SMBS + 0.5 M Cys + 2 % chitosan + CNC: Natural curly hair was washed and treated with SMBS, cysteine and chitosan as described hereinabove for Sample 3-2, except that 2 % chitosan was used instead of 2 % gelatin. After application of the chitosan, the hair was air-dried for 30 minutes and fan-dried, and then washed with water, fan-dried and iron- straightened. CNC was then spread onto the hair with a lice comb, and the hair was partially air- dried for 30 minutes and fan-dried. The hair was then straightened slowly for 2 minutes with a hot iron (with the help of a lice comb) and then washed with water and air-dried. The hair sample was washed with water twice (on days 1 and 2) and with regular shampoo on days 4, 7, 8, 9, 12, 13 and 14, and analyzed on day 15.

Sample 3-4 - 5 mM SMBS + 0.5 M Cys + 0.5 M Arg + CNC: Natural curly hair was washed with shampoo and conditioner and then fan-dried. The hair sample was straightened using a hot iron, and then, 5 mM sodium metabisulfite (SMBS) was applied on the hair (spread using a lice comb) and 0.5 M cysteine was added, and immediately thereafter, 0.5 M arginine was added and left on the hair for 15 minutes. The hair was then fan-dried and hot iron- straightened, then washed with water and fan-dried. 0.5 M cysteine and 0.5 M arginine were added again, and left on the hair for 30 minutes, which was then fan-dried and straightened with a hot iron. CNC was then spread onto the hair with a lice comb, and the hair was partially air- dried for 30 minutes and fan-dried. The hair was then straightened slowly for 2 minutes with a hot iron (with the help of a lice comb) and then washed with water and air-dried. The hair sample was washed with water 10 times, on days 1, 2, 3, 4, 7, 8, 9, 12, 13 and 14, and analyzed on day 15.

Sample 3-5 - 5 mM SMBS + 0.5 M Cys + 2 % gelatin + CNC: Natural curly hair was washed and treated with SMSBS, cysteine and gelatin as described hereinabove for Sample 3-2. After the application of gelatin, the hair was partially air-dried for 30 minutes, fan-dried, and straightened with a hot iron. CNC was then spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes and fan-dried. The hair was then straightened slowly for 2 minutes with a hot iron (with the help of a lice comb) and then washed with water and air-dried, and again washed with water and air-dried. The hair sample was washed with water 10 times, on days 1, 2, 3, 4, 7, 8, 9, 12, 13 and 14, and analyzed on day 15.

As shown in FIGs. 7-10, the use of CNC in combination with SMBS and/or cysteine in hair treatment (e.g., Samples 3-3, 3-4 and 3-5) was associated with a greater degree of hair straightening than obtained upon similar treatments with SMBS without CNC (Sample 3-2), as well as in the presence of a layer coating the hair surface after treatment (observable by electron microscopy). As further shown therein, the effect of treatment with CNC was maintained over the course of several weeks with repeated washings.

These results further confirm that application of CNC enhances the permanence of hair straightening.

EXAMPLE 2

Effect of resilin application to hair straightened using cellulose nanocrystals

Healthy curly hair was subjected to hair straightening using cysteine and cellulose nanocrystals (CNC), followed by various secondary treatments over the course of three weeks, in order to assess the effect of different secondary treatments on maintenance of the effects of the hair-straightening treatment.

Cysteine was used as a reducing agent to break disulfide bonds in the keratin structure. In order to maintain keratin unattached by disulfide bonds, hydro-keratin (hydrolyzed keratin ) was added. Positively charged molecules - arginine and the cationic surfactant BTMS (behentrimonium methosulfate) - were used to facilitate interaction of CNC with the hair surface.

Hair was washed with regular shampoo, fan-dried and subjected to the straightening treatment. A mixture of 1 M cysteine in a 100 mM MES (2-(N-morpholino)ethanesulfonic acid) solution at pH 3.5 and hydro-keratin was applied on the hair sample, spread on the hair, and left in the hair at 37 °C until semi-dried (15-30 minutes), after which the hair was dried with a hot fan. The hair was then washed with water, fan-dried and straightened at a temperature of 190 °C. 0.5 M arginine in 1 % BTMS was spread on the hair and left at 37 °C for 15-30 minutes and fan-dried. Hair was straightened at a temperature of 190 °C, and 3 % CNC was spread on the hair and left at 37 °C until semi-dried (15-30 minutes), after which the hair was fan-dried until completely dry and straightened at a temperature of 190 °C, then washed with water and air- dried.

For about 2.5 weeks after hair-straightening, the hair was washed only with water (double-distilled) and then with SLS (sodium laureth sulfate)-free shampoo.

During the following week, the hair was washed with 4 mg/ml RES-CBD (resilin with a cellulose binding domain) in water and then 2 mg/ml RES-CBD in water.

For the next two weeks, the hair was washed with SLS-free shampoo and 1 mg/ml RES- CBD in water (2-3 times per week).

The hair was then treated by applying a 50 mg/ml RES-CBD solution and letting the hair dry with the applied RES-CBD, followed by washing with water.

For about 3 more weeks, the hair was treated (every 2-3 days ) alternately by washing with SLS-free shampoo followed by 2 mg/ml RES-CBD in water, or by applying a 10 mg/ml RES-CBD solution and letting the hair dry,.

At various stages of the treatment, the hair was examined several hours after the most recent treatment, when it was completely dry.

As shown in FIG. 11, the straightened hair gradually lost its straightened form during the initial period in which it was washed only with water or shampoo (images 3-8), whereas subsequent washing with 1-4 mg/ml resilin temporarily enhanced the straightened appearance (images 9-13) until the sixth wash with resilin (image 14). The appearance of the hair was then restored by treatment with a high concentration (50 mg/ml) of resilin left on the hair to dry (image 15). Subsequently, the appearance of the hair was enhanced when resilin was applied and deteriorated when washed with shampoo (images 16-25).

These results indicate that resilin applied to straightened hair restores and maintains the effects of the hair- straightening for at least several weeks after hair- straightening treatment.

EXAMPLE 3

Effect of resilin application to previously straightened hair

The effectiveness of resilin maintenance treatment was further assessed by applying resilin from about 3 weeks to about 3 months after a variety of hair-straightening treatments Hair was washed with regular shampoo, fan-dried and iron-straightened. 0.5 M cysteine was applied on the hair and left for 15 minutes, and the hair was then fan-dried, washed with water, fan-dried and iron-straightened. 0.5 M cysteine was applied on the hair again, and immediately thereafter, 0.5 M arginine was added and left on the hair for another 30 minutes. The hair was then fan-dried and iron-straightened. CNC was applied on the hair, which was then partially air-dried for 30 minutes, then fan-dried and slowly iron-straightened, and then washed with water and air-dried. The hair was subsequently washed with water once, with 0.5 % SDS (sodium dodecyl sulfate) and 1 % NaCl five times, and with regular shampoo 21 times.

About 3 months after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry. At intervals of two days, the hair was subsequently:

washed with water and air-dried;

washed with SLS-free shampoo and air-dried; and

again washed with SLS-free shampoo and air-dried.

As shown in FIGs. 12 and 13, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, hair was washed with regular shampoo, air-dried and iron straightened. 0.5 M cysteine was applied on the hair and left for 15 minutes. 0.5 M cysteine was then applied on the hair again, and immediately thereafter, 0.5 M arginine was added and left on the hair for another 30 minutes. The hair was then fan-dried and iron-straightened. CNC was applied on the hair, which was then partially air-dried for 30 minutes, then fan-dried and slowly iron-straightened, and then washed with water and air-dried. The hair was subsequently washed with water once and with regular shampoo 20 times.

About 2 months after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 14, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, naturally curly hair was washed with regular shampoo and then with a shampoo comprising 0.5 % SDS, 1 % NaCl, 5 % glycerol and 2 % polyethylene glycol distearate, and then fan-dried and iron-straightened. 5 mM sodium metabisulfite was then applied on the hair (spread using a lice comb) and left for 15 minutes. The hair was then washed with water. 0.5 M cysteine was then applied on the hair, and immediately thereafter, 0.5 M arginine was added and left on the hair for 15 minutes. The hair was then fan-dried and hot iron- straightened, and 0.5 M cysteine and 0.5 M arginine were applied again and left in the hair for 30 minutes. The hair was then washed fan-dried and iron-straightened. The hair was subsequently washed with water four times and 0.5 % SDS and 1 % NaCl three times.

About 3 weeks after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 15, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment (which did not involve CNC).

In an additional experiment, naturally curly hair was washed with regular shampoo and conditioner, and air-dried; and then washed again with 0.5 % SDS and 1 % NaCl. 5 mM sodium metabisulfite was then applied on the hair (spread using a lice comb) and left for 10 minutes and then fan-dried and hot iron- straightened. 0.5 M cysteine was then applied on the hair (spread using a lice comb) and left on the hair for 10 minutes. 2 % cetrimonium chloride was added (spread using a lice comb) and the hair was partially air-dried for 30 minutes, then fan-dried, hot iron-straightened, and washed with water. CNC was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes, then fan-dried, iron- straightened slowly for 2 minutes (with the help of a lice comb), washed with water and air-dried. The hair was subsequently washed with 0.5 % SDS and 1 % NaCl nine times and with regular shampoo twice.

About one month after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 16, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, naturally curly hair was washed with water and soapless soap and then air dried. The hair was then iron- straightened, and 5 mM sodium metabisulfite was then applied on the hair by spreading, and left on the hair for 15 minutes. Immediately thereafter, 200 mM cysteine was added to the hair, which was then fan-dried and washed with water, fan-dried gain, and hot iron-straightened. 2 % chitosan was then spread onto the hair with a lice comb, and the hair was air-dried for 1 hour and then fan-dried, washed with water, fan-dried again, and hot iron-straightened. CNC was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes, then fan-dried, iron-straightened very slowly for 6 minutes (with the help of a lice comb), washed with water and air-dried. The hair was subsequently washed with water eight times, with regular shampoo 15 times, and with shampoo comprising 0.5 % SDS, 1 % NaCl, 5 % glycerol and 2 % polyethylene glycol distearate three times. About 3 months after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 17, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, hair was washed with regular shampoo, fan-dried and straightened. A mixture of 0.5 M cysteine, 0.5 M arginine and 2 % CNC was spread onto the hair and left for 1 hour. The hair was then fan-dried and straightened, washed with water and air-dried. The hair was subsequently washed with regular shampoo eight times.

About one month after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 18, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, naturally curly hair was washed with regular shampoo and conditioner and then fan-dried. The hair was then iron- straightened, and 5 mM sodium metabisulfite was then applied on the hair (spread using a lice comb). 0.5 M cysteine was added, and immediately thereafter 0.5 M arginine was added and left on the hair for 15 minutes; and the hair was then fan-dried and hot iron-straightened. The hair was then washed with water, fan- dried, and hot iron-straightened. 0.5 M cysteine and 0.5 M arginine were added again and left on the hair for 30 minutes, followed by fan-drying and iron- straightening the hair. CNC was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes, then fan-dried, iron-straightened slowly for 2 minutes (with the help of a lice comb), washed with water and air- dried. The hair was subsequently washed with water four times, with 0.5 % SDS and 1 % NaCl six times, with shampoo comprising 0.5 % SDS, 1 % NaCl, 5 % glycerol and 2 % polyethylene glycol distearate three times, and with regular shampoo twice.

About 1.5 months after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS- free shampoo, as described hereinabove.

As shown in FIG. 19, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

In an additional experiment, naturally curly hair was washed with regular shampoo and conditioner and then fan-dried. The hair was then iron- straightened, and 5 mM sodium metabisulfite was then applied on the hair (spread using a lice comb). 0.5 M cysteine was added and left on the hair for 15 minutes, and the hair was then fan-dried and hot iron- straightened. The hair was then washed with water, fan-dried, and hot iron-straightened. 0.5 M cysteine was added again and 2 % chitosan was spread onto the hair with a lice comb. The hair was then air- dried for 30 minutes and fan-dried, and then washed with water, fan-dried and iron straightened. CNC was spread onto the hair with a lice comb, and the hair was partially air-dried for 30 minutes, then fan-dried, iron-straightened slowly for 2 minutes (with the help of a lice comb), washed with water and air-dried. The hair was subsequently washed with water once, with regular shampoo 15 times, with shampoo comprising 0.5 % SDS, 1 % NaCl, 5 % glycerol and 2 % polyethylene glycol distearate three times, and then again with regular shampoo twice.

About 2 months after the straightening treatment, a 10 mg/ml solution of RES-CBD was applied to the hair and left to dry, followed by washing once with water and twice with SLS-free shampoo, as described hereinabove.

As shown in FIG. 20, the application of resilin was effective at restoring and maintaining the effect of the previous straightening treatment.

The above results indicate that resilin is effective at restoring and maintaining straightened hair after a wide variety of hair- straightening treatments, and remains effective for at least several months after the hair-straightening treatment.

EXAMPLE 4

Effect of cellulose nanocrystals and of cellulose nanocrystals and resilin on hair undergoing straightening treatment

Hair samples were washed with regular shampoo, fan dried and straightened. 1M cysteine in lOOmM MES pH 3.5 was spread on the hair and left for 15 minutes and thereafter fan- dried. Then, hair samples were washed with water, fan-dried and iron-straightened. Thereafter, 0.5M arginine in 1 % BTMS in DDW was spread on the hair and left 15 minutes, the hair was fan-dried and iron- straightened, and then 2 % CNC was spread on the hair and left for 30 minutes, and the hair sample was thereafter fan-dried and iron- straightened.

FIGs. 21A-D present SEM images of untreated hair sample, before the above-described treatment (FIGs. 21A and 21B) and of the hair sample following the above-described hair treatment (FIGs. 121C and 21D), with FIGs. 21B and 21D being at higher magnification. As can be seen, in the non-treated hair sample, normal cuticle scales are observed, whereby following treatment, the scales are coated and are hardly observed and are nearly invisible.

In additional experiment, hair samples were washed with regular shampoo, fan-dried and iron-straightened, and a mixture of 1M cysteine in 100 mM MES pH 3.3 and hydro-keratin was spread on the hair, left for 15 minutes and thereafter fan- dried. Then, hair samples were washed with water, fan-dried and iron- straightened, and 0. 5M arginine in 1 % BTMS was spread on the hair, left in for 15 minutes and thereafter the hair samples were fan- dried. Hair was iron- straightened and 3 % CNC was spread on the hair and left for 30 minutes, and thereafter the hair samples were fan-dried and iron- straightened.

FIGs. 22A-D present SEM images of untreated hair sample, before the above-described treatment (FIGs. 22A and 22B) and of the hair sample following the above-described hair treatment (FIGs. 22C and 22D), with FIGs. 22B and 22D being at higher magnification. As can be seen, in the non- treated hair sample, normal cuticle scales are observed, whereby following treatment, scales are coated and are hardly observed and nearly invisible. In the larger magnification shown in FIG. 22D, the CNC coating on the hair is clearly seen.

In additional experiment, hair samples were washed with regular shampoo, fan-dried and iron-straightened, and thereafter 1M cysteine in 100 mM MES pH 3.5 was spread on the hair, left for 15 minutes and the hair sample was thereafter fan-dried. Then, hair samples were washed with water, fan-dried and iron-straightened, and 0. 5M arginine in 1% BTMS in DDW was spread on the hair and left 15 minutes, and the hair was thereafter fan-dried and iron- straightened. 2 % CNC containing 10: 1 RES-CBD (1 protein to 10 CNC) was then spread on the hair and left for 30 minutes, and the hair was thereafter fan-dried and straightened.

FIGs. 23A-D present SEM images of untreated hair sample, before the above-described treatment (FIGs. 23A and 23B) and of the hair sample following the above-described hair treatment (FIGs. 23C and 23D), with FIGs. 23B and 23D being at higher magnification. As can be seen, in the non-treated hair, normal cuticle scales are observed, whereby following treatment, scales are coated and are hardly observed and nearly invisible. In the larger magnification shown in FIG. 23D, the CNC coating on the hair is clearly seen. In addition, protein clusters on the top of the CNC coating were observed.

FIG. 23E shows an observation into a gap in the hair coating. The CNC coating on the hair is clearly seen.

These data further demonstrate the effectiveness of the CNC treatment, and moreover of the combined CNC and resilin treatment.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.