DESCRIPTION

The present invention relates to compositions and materials comprising or consisting in chitin nanofibrils, lignin and at least one natural or synthesis polymer or copolymer, to a process for the preparation thereof and to biomedical, sanitary or cosmetic articles, based upon said compositions or materials and to uses thereof.

PRIOR ART STATE

In recent years, many efforts have been made towards the development of materials for medical, cosmetic and biological purposes, in particular for the development of polymer products suitable for the treatment of inflammation and tissue regeneration, cellular technology and organ transplantation. The key characteristics that these materials must have are biocompatibility and biodegradability, both as regards to the constituent polymers and to the products of their decomposition. In particular, polyglycols, polyacids, polylactones, polysaccharides and other natural and synthetic polymers are used for the preparation of the bio-absorbable matrixes (Langer R., Tirrell D. A. Designing materials for biology and medicine // Nature, 2004. Vol. 428, 6982, pages 487-492).

Foils, fabrics formed by interlacing irregularly micro/nanofibres (non-woven tissues), and porous materials based primarily upon the use of natural chitin polysaccharide (CN) (Pillai C.K.S., Paul W., Sharma C. P. Chitin and chitosan polymers: Chemistry, solubility and fiber formation // Progress in Polymer Science. 2009. Vol. 34. P. 641-678) have been recently used as matrix for biomedical applications. Due to its non-toxic nature, given that it is derived from the processing of fish and shellfish waste without depleting the environment of valuable raw materials, the use of this natural polymer is increasing year by year. (Salaberria AM.Labidi J.Fernandez Susana CM (2015). Different routes to turn Chitin into Stunning nano-objects. European Polymer Journal 68:503-515; Jounes I and Rinaudo M (2015). Chitin and chitosan preparation from marine sources: structure, properties and applications. Marine Drugs 13: 1 133-1 174).

In particular, due to its interesting properties such as absence of cytotoxicity, easy bioabsorption and ecology of its preparation procedure, all of which encourage its use in the biomedical field, the N-deacetylated chitin derivative, i.e. chitosan (CS), is amongst the most promising polymers. However, because of its high hydrophilic nature, CS-based articles are unstable, fragile, not particularly elastic and substantially rigid in the wet state. The object of the present invention is to develop materials based upon chitin in crystalline forms alternative to known materials, in particular for preparing articles destined to the use both in biomedical, sanitary and cosmetic field. SUMMARY OF THE INVENTION

The present invention is based upon the finding that mixtures of chitin nanofibrils, lignin and at least one polymer or co-polymer, presumably in form of complexes, represent starting products suitable to obtain compositions and materials equipped with properties useful for biomedical, sanitary or cosmetic applications.

The present inventors have shown that such mixtures are able to conjugate interesting pharmacological features to mechanical features suitable for the preparation of biomedical, sanitary or cosmetic articles. In particular the invention complexes are able to decrease the expression of proinflammatory cytokines (interleukin 8, interleukin 2 and TNF- alpha) which, as it is known, are over-expressed under inflammatory conditions.

Furthermore, it has been also observed that the herein described complexes are even capable to favour the tissue regeneration thanks to the capability of inducing the gene expression of metalloproteinases (MMP-2 and MMP-9) and of the beta-defensin 2.

These pharmacological features are then accompanied in the invention materials by an increased mechanical resistence due to the presence of lignin and polymer or co- polymer.

Therefore the subjects of the present invention are:

Compositions comprising or consisting in a mixture of chitin nanofibrils, lignin or a derivative thereof and at least one polymer or co-polymer.

Compositions wherein the lignin or a derivative thereof is selected among lignin derived from wood, grass, straw, kraft lignin, alkaline lignin, acetosolve lignin, steam exploded lignin, raw lignin, lignin I, lignin II or mixtures thereof.

Compositions of the invention wherein said polymer or co-polymer is selected from ethylene polyoxide, polyactic acid, and polyglycols with different molecular weight, polyvinyl alcohol, polyacrylate 6 (Nylon 6), polyurethane, polyethylene sulfur, gelatin, cellulose or chitosan, optionally in combination with glycerol or oligomer thereof, inorganic micro/nanoparticles, selected among nanoparticles of titanium dioxide, nanoparticles of silicon oxide, nanoparticles of aluminium oxide (Al ₂ 0 ₃ ), nanoparticles of zinc oxide, nanoparticles of zirconium dioxide, nanoparticles of magnesium and aluminium oxide (MgAI ₂ 0 ₄ ).

Compositions wherein chitin nanofibrils and/or lignin and/or polymer or co-polymer form a complex. Compositions of the invention in form of suspension, dispersion or solution in a liquid medium, optionally thickened or gelified, and wherein the liquid medium is an aqueous medium, hydroalcoholic medium, oleous medium.

Compositions of the invention containing from 10% to 50% (w/w) of a base suspension of 2% chitin nanofibrils.

Compositions of the invention wherein the content of Iignin and derivative thereof is comprised between 0.1% and 5% (w/w), preferably between 0.5% and 1 %.

Compositions according to anyone of claims 1 to 8, wherein the content of said copolymer is comprised between 5% and 15% (w/w).

Compositions according to the invention comprising one or more additional ingredients selected from the group: vitamins, microelements, anti-inflammatory drugs, antioxidants or anti-ageing substances, immunomodulating agents, enzymes, substances with depigmented action and metals.

Compositions wherein said metals are silver and/or bismuth and/or copper.

A material comprising the mixture of the composition according to the invention in solid form and wherein said material is a non-woven fabric, film, foil, membrane or paste, each one in form of monolayer or multilayer.

A process for preparing the composition of the invention, comprising the following steps:

- preparing an aqueous suspension of chitin nanofibrils;

- preparing a basic aqueous solution of Iignin or a derivative thereof;

- mixing the suspension of chitin nanofibrils and the solution of Iignin or a derivative thereof;

- adding to the obtained mixture at least one polymer or co-polymer;

- stirring the mixture comprising said chitin nanofibrils, said Iignin or a derivative thereof and said polymer or co-polymer for at least 48 hours; optionally

- adding, in anyone of the above-mentioned steps, one or more ingredients selected from the group: vitamins, microelements, anti-inflammatory drugs, antioxidants or anti-ageing substances, immunomodulating agents, enzymes, substances with a depigmentation action or metals.

A process for preparing the solid material according to the invention, comprising the following steps:

(a) preparing an aqueous suspension/solution comprising nanofibrils of chitin, Iignin or derivative thereof and at least a polymer or co-polymer and, optionally, one or more ingredients selected in the group: vitamins, microelements, anti-inflammatory drugs, antioxidants or anti-ageing substances, immunomodulating agents, enzymes, substances with depigmented action and metals

(b) transforming the aqueous suspension prepared in (a) into a solid material. A process according to the invention, wherein said transformation passage is carried out by means of electrospinning.

Pharmaceutical compositions containing the composition according to the invention for use in the treatment of wounds, burns, abrasions, cuts, sores, inflammations of skin and mucosae or to be used in a bacterial or bacteriostatic treatment.

A biomedical, sanitary or cosmetic article comprising or consisting in the composition or in the material according to the invention optionally being deposited or adsorbed upon a solid support.

An article according to the invention wherein said support is a polymeric support selected from the group comprising: polypropylene, polyethylene, acrylate, collagen, gelatin, polylactate.

An article according to the invention, wherein said support is a fabric with various thickness, a spongy material.

An article according to the invention in form of bandage, gauze, band, protection film, patch, face mask, gel, mono-or multy-layer ointment.

A biomedical or sanitary article according to the invention for use in the treatment of wounds, burns, abrasions, cuts, sores, inflammations of skin and mucosae, bacterial infections.

Other subject, advantages and features of the present invention will result evident from the following detailed description.

BRIEF DESCRIPTION OF FIGURES

Figure 1 shows gene espression modulation in human cell lines of proinflammatory kytokines in HaCat keratinocytes. The cell lines were treated with: control (CTR); with lipopolysaccharide (LPS) only; with samples of solution/suspension Nos.31 , 35, 40, 41 and 42 (as described in the examples). Figure 1A relates to interleukin 8; figure 1 B to interleukin 1 alpha; figure 1 C to tumour necrosis factor alpha.

Figure 2 shows gene espression modulation of metalloproteinases 2 (Figure 2A) and 9 (Figure 2b) and of beta-defensin (Figure 2C) in human cell lines of HaCat keratinocytes. The cells were treated with: control (CTR); with samples of solution/suspension Nos. 31 , 35, 40, 41 and 42 (see examples).

Figure 3 shows gene espression modulation in human cell lines of proinflammatory kytokines in HaCat keratinocytes. The cell lines were treated with: control (CTR); with lipopolysaccharide (LPS) only; with samples of solution/suspension Nos. 21 , 30 and 31 (compositions as described in the examples) or with the same samples deposited on film. Figure 1A relates to interleukin 8; figure 1 B to interleukin 1 alpha; figure 1C to tumour necrosis factor alpha.

DESCRIPTION OF THE INVENTION

Material of the invention

Chitin

The present invention provides liquid compositions or materials comprising or consisting in chitin nanofibrils, lignin or derivatives thereof and at least one polymer or copolymer.

Presumably, but not necessarily, said three components are linked in binary or ternary complex.

In the present text, under the term "chitin nanofibrils", "nanocrystals of chitin" or even simply "chitin", chitin is meant in its known form of nanometric fibrils with a thickness/diameter ranging between 2.8 and 25 nm, for example of about 8 nm and of about 200 nm in length (see WO-A-2006/048829).

Although, due to their nanometric size, chitin nanofibrils when dispersed in an aqueous medium produce a formulation with the appearance of "solution", in the present application the more accurate term of "suspension" of nanofribrils is used, as said nanofibrils are insoluble solids and therefore formally produce suspensions or dispersions. However, in the scope of the present application the terms "suspension of nanofibrils", "dispersion of nanofibrils" or "solutions of nanofibrils" are considered equivalent and interchangeable.

For convenience, chitin nanofibrils are formulated and used in a base solution/suspension containing about 2%-2.5% (w/w) of nanofibrils in aqueous solution. Therefore, unless differently mentioned, the percentage amounts of "chitin nanofibrils" indicated in the present application relate to the percentage of said base solution/suspension in the liquid mixture of chitin-lignin-polymer in a liquid medium.

The liquid mixtures of the three components usually contain about 30% of said 2% chitin base suspension/solution. Therefore, in absolute value, the suspensions of the invention usually contain about 0.6% (w/w) of chitin nanofibrils. However, different percentages of base suspension can be used for the preparation of the suspensions of the invention. Under certain circumstances, mixtures containing between 10% and 50% (w/w), for example 15%, 20%, 25%, 30%, 35%, 40%, 45% of base suspension may be also used for the purposes of the invention.

Lignin

Under the term "lignin" one relates to an organic polyphenolic polymer, consisting of three different monomers, that is cumarilic, coniferyl and sinapyl alcohol, in any of countless structures in which it is present in nature. It is known in fact that the amount of each constituent may vary depending, for example, on plant family or species. Given that lignin is widely described in the prior art it is not necessary to dwell here upon its structure and chemical/physical characteristics. The lignin of the invention is a not-functionalized lignin. Preferably, the lignin according to the invention is selected among lignin obtained from wood, preferably hard wood, such as the lignin from conifers, or grass, wheat straw or mixtures thereof. As to its preparation, the lignin can be: kraft lignin, alkaline lignin, acetosolve lignin or steam exploded lignin. Regardless of its origin, lignin may also be raw lignin, lignin I, which is the purest fraction obtained from raw lignin or lignin II, which is the carboxylated fraction of lignin I. In a specific embodiment the lignin is obtained from wheat straw.

Preferably, the lignin or a derivative thereof is selected from lignin having:

(a) a weight average molecular weight ( w) in the range from 12,300 Da to 14,300 Da and polydispersity in the range from 3.1 to 2.5, and a polymerization degree comprised between 12 and 18; or

(b) a weight average molecular weight( w) in the range from 2,300 Da to 4,300 Da and polydispersity in the range from 2.8 to 4.6, and a polymerization degree in the range from 3 to 4; or

(c) a weight average molecular weight(Mw) in the range from 6,300 Da to 8, 100 Da and polydispersity in the range from 2.3 to 3.1 , and a polymerization degree comprised between

9 and 10.

The lignin content in the liquid mixtures of the invention is comprised between 0.05% and 5% (w/w) of the mixture itself, for example 0.1 %, 0.3%, 0.5%, 0.8%, 1 %, 2%, 3%, 4% or 5%. In a preferred embodiment the percentage of lignin is less than 1 %, and most preferably between 0.1 % and 0.5%.

Without wishing to limit the invention to particular theories, chitin nanofibrils and lignin appear to form complexes with each other by means of ester or ether bonds together with the involvement of lignin phenolic hydroxyls. Such complexes seem to be able to entrap active molecules or substances.

Polymer or co-polymer An additional component of the compositions and materials of the invention is the polymeric component, namely a polymer, a co-polymer or mixtures thereof. The function of this component is to confer, together with lignin, the best mechanical properties to the materials and articles of the invention, in particular the required consistency, thus carrying out a substantially structural or thickening function.

Said polymeric component can be selected from the group comprising ethylene polyoxide (PEOX) at different molecular weight, for example, PEG from 400 to 8000, for example PEG 600, 800, 1000, 2000, 3000, 4000, 5000, 7000, polyvinyl alcohol (PVA), PA 6 (Nylon 6), PUR (Poly Urethane), PES (Poly Ethylene-Sulfide); natural biopolymers such as gelatin, cellulose or chitosan or polyactic acid. Such polymeric material may be in form of organic fibres or nanofibres.

Optionally, in addition to the organic polymeric component, the mixture of the invention may comprise glycerol, or the oligomers thereof, such as diglycerol, triglycerol, tetraglycerol, a polymer based upon inorganic nanoparticles such as: Titanium dioxide, Silicon Oxide, Aluminium Oxide (Al ₂ 0 ₃ ), Zinc Oxide, Zirconium Dioxide, Magnesium and Aluminium Oxide (MgAI ₂ 0 ₄ ).

Preferably, the polymer component content is comprised between 5% and 15% (w/w) of the liquid mixture, for example 6%, 7%, 8%, 9%, 10%, 11 %, 12%, 13%, 14%. However, higher amounts of polymer or a mixture of polymers, up to 30%, 40%, 50%, 60, 70% or 80% can be used under particular circumstances to obtain the wished mechanical properties of the end material.

Obviously the percentage of the liquid medium in the compositions in form of the solution/suspension represents the complement at 100% (q.b. at 100%). Such solvent preferably is water.

The compositions and the materials of the invention can further comprise one or more additional components selected among: vitamins (for example vitamins A, C, E), microelements (for example fluorine, selenium, iron, zinc, iodine), anti-inflammatory drugs, (for example nicotinamide, creatine, the glycyrrhetinic acid, phytosphingosine, polyunsaturated fatty acids PUFA, corticosteroids zinc-pyrithione and pyrithione olamine, ketoconazol, chlorexidine gluconate, glycin, benzoyl peroxide) antioxidants (for example carotenoids, such as beta-carotene, lutein, zeaxanthin, phytoestrogens, lycopene, proantocianines, flavonoids and polyphenols, tannins, lipoic acid, tocotrienols and Q10 coenzyme, ascorbyl phosphate sodium) or anti-ageing substances, immunomodulating agents, (for example melatonin, ectoin, beta-glucan, carboxymethylbeta-glucan, gluconate, lactate and zinc picolinate) enzymes, substances with a depigmentation action, metals. The metals could be for example silver and/or bismuth and/or copper. In particular, the metals listed above may themselves form a complex with the chitin nanofibrils in anyone of the respective oxidation states or in metallic form. For example silver forms a complex with chitin nanofibrils in its elementary metallic state (oxidation state 0); bismuth can form a complex with chitin nanofibrils in its +2 or elementary oxidation state; copper can form a complex with chitin nanofibrils in its +1 , +2 o elementary oxidation state. In one embodiment of the invention the chitin nanofibrils form a complex with one or more of the metals Ag, Cu and/or Bi in their elementary state.

If the materials of the invention form complexes with the metals listed above, these complexes will feature antibacterial/antifungal activity.

The compositions of the invention can be used both as such in liquid form and transformed in solid material.

The liquid forms are suspensions, dispersions or solution in a suitable medium, optionally thickened or gelified and then even in form of gel. The medium can be pure water or aqueous or hydroalcoholic solution, or oily medium. In a second embodiment, the compositions of the invention are transformed into solid material. To the purposes of the present application, with the term "solid material" not necessarily a solid, dehydrated and rigid material is meant, but a material with any solid, half-solid, elastic, plastic or pasty consistency. Said material for example is a non-woven fabric, film, foil, sponge, sheet, mono-layer or multi-layer membrane or paste.

Optionally the compositions or the materials, in anyone of the liquid or solid physical forms indicated above, is/are deposited upon a solid support, which can be either soft, rigid or elastic. Preferably, the support is polymeric and selected from the group comprising: polypropylene, polyethylene, acrylate, collagen, gelatin, polylactate or other equivalent bio- compatible polymers. Alternatively, the support may be a fabric with variable thickness, a spongy materiale or an absorbent matrix. In a specific embodiment of the invention, the material in suspension or solution, or even concentrate, is adsorbed onto an absorbent matrix. Process for the preparation of the liquid compositions of chitin nanofibrils, lignin and polyme

The aqueous suspension of the substances according to the invention, presumably in form of complexes, can be prepared according to a process comprising the following steps:

- preparing one first aqueous suspension of chitin nanofibrils;

- preparing a basic aqueous solution of lignin or a derivative thereof;

- mixing the suspension of chitin nanofibrils and the solution of lignin or a derivative thereof;

- adding to the obtained mixture at least a polymeric material, polymer or copolymer;

- stirring the mixture comprising said chitin nanofibrils, said lignin or a derivative thereof and said polymeric material for at least 48 hours.

In order to facilitate the dissolution of lignin, the aqueous solution containing it can be adjusted to a basic pH by adding a base, for example NaOH, preferably at a concentration of 0.1 M.

The concentration of chitin nanofibrils, lignin and the polymeric material in the respective suspensions or solutions is such to allow the preparation of a material containing said components in the amounts and proportions described above.

In the embodiments wherein the suspension comprises one or more additional ingredients, as indicated above, the process provides that these components are added in anyone of the steps indicated above. In particular, then they may be added: in the chitin suspension and/or in the lignin solution or in the suspension obtained by mixing said first suspension and said solution or in the final suspension comprising chitin nanofibrils, lignin and the co-polymer. In particular, if silver, copper and bismuth in metalli form are added the process of the invention includes a step of adding the metals Ag, Cu and/or Bi in salified ionic form and a reduction step of the same in the presence of chitin nanofibrils according to the following. Preferably, the reduction step is performed before adding lignin.

The metal ions can be added for example, as nitrate, sulphate, chlorate or other usual Salts.

The reduction reaction of metal ions can be carried out by a person skilled in the art according to any known method. By way of example, the reduction may be carried out in the presence of a reducing agent such as glucose, starch, sucrose, fructose, ascorbid acid or any other natural reducing agent that is compatible with human physiology.

In particular, the concentration of the reducing agent can be comprised between 0.1 and 2.5% (w/w). The reaction is carried out by stirring the aqueous suspension comprising chitin nanofibrils and metal ions for a period of 5-10 minutes. Preferably this procedure is carried out at a temperature comprised between 20-25°C. Preferably, the reducing agent is glucose.

Table 1 lists some example mixtures of the invention. The w/w percentages of the single components in the aqueous suspension are illustrated. Content (% w/w)

PEOX Lignin Additional component water

% %

No. 1 7% powder Wheat straw 0.1 % Chitin-nanofibrils 30% NN 62.9% powder (2% suspension w/v)

No. 2 7% Wheat straw 0.1 % Chitin- nanofibrils + Ag 62.9%

30%

No. 21 7% Wheat straw 0.1 % Chitin- nanofibrils 30% 62.9%

No. 23 7% Wheat straw 0.1 % Chitin- nanofibrils 30% 62.9% collagen 0.1

No. 30 7% WS ASOL 800 HEX Chitin- nanofibrils 30% 62.9%

0.1 %

No. 31 7% WS F3 (MeOH) Chitin- nanofibrils 30% 62.9%

0.1 %

No. 34 7% WS ASOL 800 HEX Chitin- nanofibrils 30% 62.5%

0.5%

Process for the preparation of the material in solid form of the invention

The process for the preparation of the above-described material comprising or consisting in the mixture of chitin nanofibrils, lignin and at least one polymer or co-polymer provides the following steps:

a) preparing the aqueous suspension/solution described above of chitin nanofibrils, lignin and at least one polymer or co-polymer and, optionally, one or more ingredients; b) transforming said aqueous formulation into a solid material.

The obtained material can be in form of thin layer, for example a sheet, a plate, a film, a foil, a non-woven fabric etc. featuring variable thickness as needed. The thickness of said thin layer, regardless of the used technique, varies in the order of nanometres to millimetres, for example from 200 nm to 5 mm, preferably from 0.5 micron to 1 mm, or from 1 micron to 0.5 mm. For example, the thickness could be 200 nm, 300 nm, 500 nm, 800 nm, 1 micron, 10 micron, 50 micron, 100 micron, 800 micron, 1 millimetre, 5 millimetres.

The transformation of the suspension into a thin solid or paste layer can be carried out according to any full or partial drying technique capable of transforming the suspension in accordance to what is indicated herein.

In an embodiment of the invention, the used technique is electrospinning.

Electrospinning: Starting from the suspension as described above, electrospinning, also referred to as electrostatic spinning, allows in obtaining filaments constituting or comprising chitin and lignin monofilaments. These filaments have a section diameter lower than 100 nm and a length of several millimetres or even centimetres.

To this end electrospinning can be carried out by using the NS LAB 500S equipment based on Nanospider Technology and produced and marketed by Elmarco company (www.elmarco.com).

Advantageously, by using the Nanospider Technology technique, a thin layer that is in the form of non-woven fabric is obtained.

Depending upon the adopted operating mode, as will be apparent to a person skilled in the art, both a monolayer and multi-layer (with at least two thin layers) form of non-woven fabric can be obtained. In fact, by transforming nanochitin and lignin suspensions with different compositions in sequence by means of electrospinning, for example suspensions comprising several additional components, it is possible obtaining multi-layer fabrics wherein each layer can have the same or different chemical and physical characteristics.

To the purpose of the present invention, electrospinning can be carried out at a temperature ranging between 18°C and 30°C at a voltage ranging between 5 and 60kV, preferably between 5 and 45kV. Furthermore, depending upon the operating conditions, electrospinning may be carried out at a flow rate varying from ml/h to m ³ /h. In addition, electrospinning may be conducted in an environment with a relative humidity between 20- 25%.

Biomedical articles

The mixtures of the present invention, both in form of liquid compositions and solid materials are used for implementing biometical, sanitary, cosmetic or comfort articles. The biomedical articles are articles capable of influencing or re-establishing the normal physiology of a fabric, organ, organism, therefore they have mainly therapeutic purposes. The sanitary articles are articles capable of maintaining the normal health state of fabrics. On the contrary, cosmetic or comfort articles have no medical purposes, but purely cosmetic purpose.

By way of example such articles can be medication means, such as bandages, gauzes, bands, protection films, patches, cosmetic means such as face masks, gels, lotions, ointment.

The articles of the invention themselves can be multi-layer, comprising several layers of one same type of material or several layers of different types of material.

The herein described biomedical articles are suitable to contrast inflammation and/or to favour the tissue regeneration and therefore they can be used for treating all the conditions wherein an inflammatory alteration of the skin and mucosae is observed. By way of example, the herein described articles can be used as medication and/or protection in treating wounds, burns, abrasions, cuts, sores, inflammations of skin and mucosae, insect punctures, reeds, skin hyperpigmentation. Comfort articles may be used for example to contrast the natural ageing or early ageing or hyper-pigmentation of skin or for rehydrating the skin.

EXAMPLES

The following examples have purely illustrating purposes and they are not destined to limit the invention as otherwise described in the present application.

EXAMPLE 1 : Preparation of the suspension comprising nanofibrils of chitin, lignin and PEOX as polymer.

The complexes of the invention have been prepared according to the herebelow detailed process.

1. placing 125.8 g of distilled water in a becher;

2. adding chitin nanofibrils (60 g of 2% suspension) under stirring;

3. adding lignin (0.2 g);

4. stirring the mixture by entering a minimum amount of 0.1 M NaOH with the purpose of favouring the lignin dissolution;

5. adding polyethylenglycol oxide (PEOX) (14 g);

6. letting the mixture to rest for two days by stirring every 6 hours to eliminate each air bubble.

In the end a solution/suspension with brown caramel colour was obtained, thereof pH (10.52 due to the addition of NaOH), viscosity (8400 cPs) and electroconductivity (7.8 milliSiemens) were measured.

EXAMPLE 2: Evaluation of the features of the film obtained by means of electrospinning. The film obtained by means of electrospinning starting from an aqueous solution of the complexes comprising chitin, lignin nanofibrils and a support polymer was analyzed by means of gel permeation cromathography. The UV detection allows analysing selectively the fractions chemically linked to the lignin fraction, which is the only active UV.

Table 2 shows GPC (Gel Permeation Cromathography) profiles of the various obtained films. In particular the increase in Mn (number average molecular weight) and Mw (molecular weight) of the products with respect ot the starting profile is evident, with an intense exclusion band with high molecular weights. These profiles show deary that in the films the ligning not only is accompanied by chitin, but it is chemically linked thereto and/or to the co-polymer.

A second experiment was carried out by using nuclear magnetic resonance and phosphor 31. Lignin does not include phosphorous, but the marking thereof allows entering phosphorous in selective and quantitative way at the phenolic hydroxyls. In this way, in presence of a suitable inner standard, it is possible performing the quantitative and qualitative analysis of the phenolic hydroxyls and of the carboxylic groups existing in the film. A decrease in the carboxylic groups is evident. This shows that probably lignin is linked to the chitin nanofibrils by means of ester bonds, (table 3)

Table 2

Mn Mw polydispersion

Wheat straw 3900 (±300) 13300 (±1000) 3.3 (±0.2)

No. 1 6500 54200 8.4

No. 2 5400 32700 6.1

No. 21 3300 27500 8.3

No. 23 3844 25745 6.7

WS ASOL 800

HEX 740 (±190) 2740 (±490) 3.8 (±0.5)

No. 30 2900 23300 8.0

No. 34 2900 23400 8.0 Table 3

PHARMACOLOGICAL ACTIVITY OF SUSPENSIONS

The following formulations were produced and subjected to tests of pharmacological activity.

Sample No. 30: Peox 7%, Lignin I, 0.1 %, CN 30% (w/w). Sample weight: 567 mg. Diluted in 5.67 ml of saline solution.

Sample No. 31 : Peox 7%, Lignin II, 0.1 %, CN 30% (w/w). Sample weight: 389 mg. Diluted in 3.89 ml of saline solution.

Sample No.21 : Peox 7%, Raw lignin, 0.1 %, CN 30% (w/w). Sample weight: 420 mg, diluted in 4.2 ml of saline solution.

Sample No. 35: PEOX 7%, CN 30% (w/w). Sample weight: 370 mg, diluted in 3.7 ml of saline solution.

Sample No. 40: PEOX 7%, Lignin (Heiko) 1 %, CN 30% (w/w). Sample weight: 290 mg, diluted in 2.9 ml of saline solution to obtain a lignin concentrartion equal to 1 mg/ml.

Sample No.41 : PEOX 7%, Lignin (Heiko) 5%, CN 30% (w/w). Sample weight: 260 mg, diluted in 2.6 ml of saline solution to obtain a lignin concentration equal to 5 mg/ml.

Sample No. 42: PEOX 7%, Lignin 2.5%, CN 30% (w/w). Sample weight: 230 mg, diluted in 2.3 ml of saline solution to obtain a lignin concentration equal to 2.5 mg/ml.

Sample No. 49: PEOX 7%, Lignin II 0.1 %. Sample weight: 370 mg, diluted in 3.7 ml of saline solution.

Sample No. 50: PEOX 7%, Raw lignin 1 %. Sample weight: 370 mg, diluted in 3.7 ml of saline solution.

Comparison samples

By way of comparison, three compositions were produced comprising only the mixtures/complexes of chitin nanofibrils (30% base suspension) and lignin at 0.1 %, precisely Lignin I, Lignin II and Raw lignin. Such samples did not include then any polymer or co-polymer.

Sample No. 35 does not include Lignin. Samples No. 49 and No. 50 do not include chitin. These samples were used as comparison samples for the pharmacological activity.

EXAMPLE 3. Determination of the reparative, anti-inflammatory and antibacterial activity of the materials of the invention.

The substances to be tested were diluted in serum-free DMEM and those that after solubilization were basic (pH9) were proceeded by bringing the pH value up to a physiological value of about 7. Subsequently, the solutions were sterilized by means of autoclaving. The substances that, instead, were already present in solution were first of all sterilized in autoclave and subsequently brought up to physiological pH by of 1 : 100 dilution in DMEM at time of experiment. The "polypropylene support" sample is sterilized in autoclave after being reduced in small-sized fragments.

Experimental procedures

The immortalised human keratinocyte cell line, HaCaT, was cultivated in DMEM to which 10% fetal bovine serum (FBS) and pennicillina-streptomicyn (100 U/ml) was added at 37°C in an atmosphere of 5% C0 ₂ . In a routine manner, the cells were plated in 6-well tissue cultural plate and used at 80% confluence. Before any treatment, in order to stop growth and to synchronize the cell culture, the semi-confluent monolayers were deprived of nourishment using serum-free DMEM.

Subsequently, in order to verify tissue regeneration activity, the anti-inflammatory and antibacterial activity of the tested substances, the cell cultures were treated (i) with the samples of the invention and with lipopolysacharides (LPA) from P. aeruginosa, which is known for its ability to induce a strong inflammatory response to a concentration of 10 μg/ml in this order; (ii) only with the samples of the invention. For the evaluation of the antibacterical activity, cultures of Pseudomona. a and Staphylococcus a were treated with samples Nos. 30 and 31.

A Real-Time PCR was carried out in order to assess:

expression within the cells treated with the Beta-defensin 2 (hBD-2), and metalloproteinases 2 and 9 (MMP-2 and -9) samples of the invention, which are involved in the tissue regeneration mechanisms;

expression within the cells simultaneously with the samples of the invention and with LPS, proinflammatory cytokines, particularly interleukin 8 (IL-8), interleukin 1-alpha (IL- 1), and tumor necrosis factor alpha (TNF-alpha).

All treatments were performed in triplicate for 6 or 24 hours, with the only exception of polypropylene (reference) the activity thereof was assessed after 24 hours. At the end of the experiment, the total RNA was isolated and 200 ng used for reverse transcription into cDNA by using commercial random hexamer primers at 42°C for 45 minutes according to manufacturer's instructions. A Real time PCR was carried out using the LC Fast Start DNA Master SYBR Green kit using 2pl of cDNA which corresponds to 10ng of total RNA in a final volume of 20pl, 3mM MgCI ₂ and 0.5pM of sense and antisense primer by using commercial primers. RESULTS

The results relating to the expression of the pro-inflammatory cytokines IL-8, IL- lalpha and INF-alpha in the cells treated with samples Nos. 31 , 35, 40, 41 and 42 are listed in the tables and illustrated in the block diagrams of Figures 1A, 1 B, 1C. It should be noted that sample No. 35 is the comparison sample which does not contain lignin, while samples Nos. 31 , 40, 41 and 42 include 0.1 %, 1 %, 5% and 2.5% Lignin, respectively.

The results in Figure 1 show that sample 31 containing low percentages of Lignin (0.1 %) is able to greatly reduce the expression of pro-inflammatory cytokines (IL-8, IL- lalpha and TNF-alpha), whereas the samples containing higher percentages of lignin (40, 41 and 42) are less effective. It should be noted that the comparison sample No. 35, which does not contain lignin is not effective in significantly reducing the expression of cytokines in none of the tests.

In another series of tests the cells were treated with samples Nos. 21 , 30, 31 and with the three samples containing only the complexes of chitin nanofibrils and lignin, but without polymer. In parallel tests, the samples were tested both deposited on films and in liquid phase (solution/suspension). It should be noted that the three samples Nos. 21 , 30 and 31 include 0.1 % Lignin I, Lignin II or Raw lignin, respectively. The results are shown in tables and illustrated in the block diagrams of Figures 3A, 3B and 3C.

The results in Figure 3 show that the samples 21 , 30 and 31 , all containing 0.1 % lignin, are capable, after 6 and 24 hours, of significantly decreasing the degree of expression of pro-inflammatory cytokines induced by LPS, in comparable manner. In addition, the comparison of the results obtained with the three samples shows that there are substantial differences in the pharmacological effect between the different types of lignin tested (Lignin I, II or Raw lignin).

Results observed by the present inventors that are not reported here have also shown that the same level of effectiveness regarding samples Nos. 21 , 30 and 31 was observed with samples containing only chitin nanofibrils and lignin. This confirms that the polymer or co-polymer present within the mixtures of the invention offers a merely mechanical function. Figures 2A, 2BV and 2C refer instead to the expression of the metalloproteinases (MMP-2, MMP-9) and of the human beta-defensin 2 (hBD-2). All samples Nos. 31 , 40, 41 and 42 showed to have a positive effect in the tissue repair process mediated by induction of the hBD-2 expression (Fig. 2C), whereas with sample No. 35 (not containing lignin) no activity was observed in this regard. As to the MMP-2 and MMP-9 metalloproteinases expression induction tests, the sample No. 31 (containing 0.1 % lignin) demonstrated high effectiveness in the induction of their expression, whereas samples containing high percentages of lignin did not demonstrate statistically significant and different activities from sample 35 (not containing lignin).

The strong effectiveness of sample No. 31 in the expression induction of MMP-2 and MMP9 and hDB2 was confirmed (data not reported herein) in a parallel series of tests carried out with samples Nos. 21 , 30 and 31. It should be noted that none of the above-illustrated compositions Nos. 21 , 30, 31 ,

35, 40, 41 and 42, not including metals, demonstrated antibacterical activity. In fact, the bacterial activity is linked to the presence of the metals.

In another series of tests, the cell lines were treated with samples Nos. 49 and 50 containing lignin II at 0.1 % or raw lignin at 1 %, but not containing chitin nanofibrils. In relation to sample No. 49 an increase neither in hBD2, nor in MMP was observed, therefore the substance does not seem to favour the tissue repair. In relation to the sample No. 50 a moderate increase in hBD2, but not in MMP-2 and 9, was observed, therefore the substance favours only partially the tissue repair.

As to the anti-inflammatory activity, the two samples decrease considerably both pro-inflammatory cytokines and TNF-alpha, therefore the substance has an antiinflammatory activity.

The invention has been sofar described with reference to the embodiments. As it will result evident to a person skilled in the art from what detailed, even additional embodiments belonging to the same inventive core may be provided, which however are to be meant as within the protective scope defined by the claims of the present application.