Title of Invention :Novel antibacterial nanometal oxide used in detergents, and preparation method

Technical Field

[0001] The present invention, in some embodiments thereof, relates (not exclusively) to material science and more particularly metal oxide nanoparticles, processes of preparing same, and uses thereof in, for example, antibacterial detergents for reducing or preventing growth of microorganisms.

[0002] Furthermore the present invention relates to the field of daily chemical compounds and in particular relates to antibacterial detergent liquid as well as a preparation method and application of the antibacterial detergent liquid.

Background Art

[0003] Microorganism resistance to antibiotic treatments has increased in recent decades, becoming a concern due to potential harmful effects on human health. As a result, increasing occurrences of genes with higher resistance to antibiotics have been detected in certain bacteria that come in contact with humans and other animals’ species . Considering the need to find new alternatives for the control of bacterial and fungal proliferations in uncontrolled environments, several studies have been published using concepts regarding the interaction of nanostructured materials and microorganisms, studying the possible effects of this contact .

[0004] Metal oxide nanoparticles (MONPs), especially iron (Fe)-based ferrites are great interest due to their unique optical, electronic, magnetic, biomedical and biological applications. Monodisperse magnetic ferrite NPs have gained a new impetus in application fields such as Ferro fluids, biological imaging and therapies, magnetic resonance imaging (MRI), and drug delivery, where magnetic NPs are extensively used. Superparamagnetic metal oxide nanoparticles (SPIONs)of spinel ferrites attract many attentions due to their unique behavior that occurred in range of below 30 nm and make metal oxide suitable for using in biomedical application. In the crystal structure of ferrites that are usually cubic close-packed oxides, the tetrahedral and octahedral sites are occupied by divalent and trivalent cations. The substitution of the Fe2+ ions in ferrite structures with different metal such as Zn2+, Ni2+, Mn2+, Cr2+ and Cu2+ ions allow variations in their properties that can be tuned for specific applications. Using some diamagnetic and paramagnetic material such as copper (Cu), zinc (Zn), mangenues (Mn), magnesium (Mg) etc, cause reach to this propose. The most of the transition metal-substituted ferrite NPs have been studied only for their magnetic properties, with few having been applied for biomedical applications. So magnetic NPs requires modification to increase the biocompatibility and bacterial activity before implementation for drug delivery applications. Inorganic antibacterial agents such as metal and metal oxides are advantageous compared to organic compound due to their stability, loannis L. Liakos, et.al reported in their research that magnetic NPs, have been found to be effective in fighting infectious diseases. On the other hand, The use of silver metal particles as antibacterial agents is noteworthy, due to their advantages in terms of chemical stability, resistance to temperature variations, efficacy and long-term durability. These advantages can be extended by considering the relatively low toxicity of these particles to the human body compared to other inorganic metals . An example of the attractiveness of these nanoparticles is applications in water-purifying systems, widely diffused in the industry.

[0005] CN 108300586 describes water-based detergent, which is prepared from the following raw materials in parts by weight: 20-30 parts of nano zinc oxide dispersion liquid, 30-40 parts of fatty acid or salts thereof, 8-14 parts of a nitrogen-containing nonionic surfactant, 4-10 parts of isomeric alcohol polyoxyethylene ether, 1 -3 parts of cationic polymer, 5-9 parts of plant extract, 1 - 3 parts of inorganic base, 8-14 parts of dibromomethane, 6-10 parts of alkyl glycoside, 12-18 parts of water-soluble silicone oil and 50-70 parts of water.

[0006] WO 2011/033040 describes a method of preparing ZnO nanoparticles doped with Cu or Mg.

[0007] WO 2011/033040 teaches that Cu-doped or Mg-doped ZnO nanoparticles have a higher antibacterial activity than ZnO nanoparticles.

[0008] WO 2008/077239 A2 describes nanocapsules with a core-shell structure, the shell comprising at least one metal oxide.

Summary of Invention [0009] This invention discloses novel antibacterial liquid detergent based on nanometal oxides, as well as evaluation of the interaction and inhibition rates caused by exposure to the bacteria. Functional nanoparticles with superparamagnetic and antibacterial properties were obtained through the solution combustion method, aiming viable options in the control agonists including: Staphylo-coccus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), Klebsiella pneu-moniae (K. pneumoniae) and Enterococcus faecalis (E. faecalis)

Technical Problem

[0010] Bacteria have become resistant to antibiotics and many antibacterial agents, which can be inherited and cause infectious diseases to spread easily, which is one of the biggest health challenges in the world.

[0011] In order to overcome the deficiencies in the prior art and shortcoming, the primary and foremost purpose of the present invention is in that to provide a kind of Antibiotic detergent especially in liquid form, and the antimicrobial moiety of this liquid detergent selects cheap Nanometer iron oxide, has a broad antifungal spectrum, antimicrobial efficiency advantages of higher. Present invention is to the preparation method that above-mentioned Antibiotic liquid detergent is provided by following descriptions.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0012] The invention relates to the field of daily chemicals and in particular relates to antibacterial detergent liquid as well as a preparation method and application of the antibacterial detergent liquid. The antibacterial detergent liquid is prepared from the following components: an anionic surfactant, a preservative poly ethylene glycol, essence, zinc nitrate, silver nitrate, iron nitrate and water. All metal salt is dissolved into a reaction solvent and will add the surfactant and adjust the pH near 7 then microwave hydrothermal reaction is carried out to obtain the nano AgZnFe204. On the basis of ensuring the stability of all the components nanoparticles will disperse in PEG , the added nano particles and the other components have a synergistic facilitation effect, so that common bacteria, such as Coli bacillus and Staphylococcus aureus, on the surfaces of table, door handle and surface can be effectively inhibited and removed; the detergent liquid prepared by the invention is low in cost and good in dirt removing effect, and can be used for effectively removing oil stain.

[0013] The Propose of Material Selection:

[0014] Microorganism resistance to antibiotic treatments has increased in recent decades, becoming a concern due to potential harmful effects on human health. As a result, increasing occurrences of genes with higher resistance to antibiotics have been detected in certain bacteria that come in contact with humans and other animals’ species such a situation is even more serious when the immunity of certain microorganisms stems from the indiscriminate use of antibiotics against any pathogen, resulting in side effects that reflect growing bacterial resistance to many antibiotics. Considering the need to find new alternatives for the control of bacterial and fungal proliferations in uncontrolled environments, several studies have been published using concepts regarding the interaction of nanostructured materials and microorganisms, studying the possible effects of this contact

[0015] Functional nanoparticles with superparamagnetic and antibacterial properties were obtained through the solution combustion method, aiming viable options in the control agonists including: Staphylo-coccus aureus (S. aureus),

Pseudomonas aeruginosa (P. aeruginosa), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), Klebsiella pneu-moniae (K. pneumoniae) and Enterococcus faecalis (E. faecalis)

[0016] Synthesis of ferrite nanoparticles Zn1-xAgxFe204 and evaluation of potential antibacterial activity

[0017] Synthesis

[0018] Zn-Ag ferrite nanoparticles were synthesized by a modification of the simplified solution combustion method. A stoichiometric mixture of zinc nitrate, silver nitrate and ferric nitrate was diluted with the redacting agent glycine (C2FI5N02) in a vessel containing deionized water, at masses previously defined for the desired composition of the final product and in the stoichiometry for the complete consumption of the oxides by the complexing agent. Two ratios between the reducing agent and the oxidizing agents were evaluated, fixing the glycine nitrate (G:N ratio) molar ratio at 1 :1 and 2:3. The reaction components were then heated to 10OC until an exothermic redox reaction between the fuel and the oxidizing agent occurred homogeneously. This solution was brought almost instantaneously to the self-sustained simultaneous combustion process in the entire solution volume, resulting in a high-volume powder with dark precipitates, defined by the amount of oxide present in the samples.

[0019] Preparation of the culture medium and strain selection

[0020] Gram-positive strains S. aureus, B. subtilis and E. faecalis and Gram-negative P. aeruginosa, E. coli and K. pneumoniae were selected for quantitative bioassay analyses with ferrite samples Zn0.95Ag0.05Fe204and Zn0.98Ag0.

02Fe2O4.With the aid of an inoculating loop, a fragment of the pre-served bacterium was removed and transferred to a Petri dish containing Mueller— Hilton Agar culture medium. After incubating for 24 h, an aliquot of the bacteria was transferred into a test tube containing 5.0 ml_ of Mueller-Flinton broth culture medium. All tubes were then incubated for 4 h at 37°C for bacteria activation and synchronization. A total of 1.0 ml_ of the grown bacteria were transferred to a tube containing 1 ml_ of 10% formaldehyde. The number of colonies was measured at 625 nm on a UV-vis spectrophotometer (Thermo Spectronic Genesys 10 UV). The concentrations were then adjusted between 106— 107CFU/ml_ in tubes containing 5.0 ml_ of Mueller-Flinton broth medium.

[0021] The invention can be used in powder form or any other suitable form as an additive to detergents or as a coating on surfaces.

[0022] The antibacterial detergent liquid based on the nanometal is prepared from the following components: an anionic surfactant, a preservative poly ethylene glycol, essence, zinc nitrate, silver nitrate, iron nitrate and water. All metal salt is dissolved into a reaction solvent and will add the surfactant and adjust the pH near 7 then microwave hydrothermal reaction is carried out to obtain the nano AgZnFe204. On the basis of ensuring the stability of all the components nanoparticles will disperse in PEG , the added nano particles and the other components have a synergistic facilitation effect, so that common bacteria, such as Coli bacillus and Staphylococcus aureus, on the surfaces of table, door handle and surface can be effectively inhibited and removed; the detergent liquid prepared by the invention is low in cost and good in dirt removing effect, and can be used for effectively removing oil stain. [0023] Sample separation and incubation

[0024] Zn-Ag ferrites with structural composition Zn0.98Ag0.02Fe204 and Zn0.95Ag0.05Fe204, at silver ion concentrations of 2%and 5%, respectively, were tested. The zinc-silver samples underwent molecular modifications during the synthesis step, adjusting a higher number of oxidants per reagent (G:N ratio of 1 :1 and 2:3), in order to investigate possible effects induced by changes in the stoichiometry of the reaction in the process of bacterial activity mitigation. The ferrite samples were separated according to their chemical structure, in order to investigate bacterial growth inhibitory processes and the Ag+ ion ratios in these processes. To this end, four zn-Ag ferrite samples were used. Sample masses were selected for the concentrations of 250 g/ml_ and 500 g/ml_. A volumetric concentration of 5.0 L of bacterial culture at 107CFU/ml_ were added to the samples, adjusted by the growth density in each culture. Each sample was homogenized a total of three times with the culture medium to remove large aggregates. The samples were then maintained under incubation conditions (Edmun Buhler TFI-30) with axial shaking at 115 rpm at 36-37°C, overnight. All assays were performed in triplicates to ensure total reproducibility and reliability.

[0025] The fundamental research on spinel NPs has been explored due to their versatile utility as photo catalysts for their antibacterial activities. Bacterial microbes’ Gram-positive strains S. aureus, B. subtilis and E. faecalis and Gram negative P. aeruginosa, E. coli and K. pneumoniae can be frequently found in waste water, flood water that are responsible for skin diseases and easily carry by human and animal body. In particular, different type of bacteria are the human effective microorganisms causing infections to nails, skin and mucosal surfaces. The substitution of metal in Fe304 spinel structure ferrite NPs provides a new composite material possessing good physical properties and antimicrobial active nature. NPs with antibacterial activity can be found in huge applications like food processing and packaging, textile industry, biomedical devices and water disinfection and surface coating. So, providing the modification of NPs by choosing the best method of preparation and suitable material is very important. Different techniques have been developed to fabricate ferrite NPs, and among of these techniques, sol-gel auto combustion technique offers enhanced control over homogeneity, elemental composition and powder morphology. In addition, uniform nano-sized metal clusters can be achieved using sol-gel technique, which are crucial for optimizing the properties of the NPs. These advantages favour the sol-gel route over other conventional preparation methods of ceramic oxide composites.

[0026] Both the products’ liquid characteristics and the bottles’ spray mechanisms played roles in determining the size distribution of total aerosols, and the size of NPs-containing aerosols emitted by the products was largely independent of the NPs size distributions in the liquid phase.

[0027] X-ray diffraction patterns of grown Ferroso-ferric Oxide (Magnetite) and metal substituted ferrite NPs is shown in Fig.1 The diffraction peaks at 30.12°, 35.54°, 37.12, 43.13°, 53.41 °, 56.89° and 62.62° are indexed as the reflection planes of (220), (311), (222), (400), (422), (511) and (440) respectively which confirms the formation of the cubic spinel structure. No XRD peaks associated to the other phases are detected, which infers the complete substitution of transition metals in the Magnetite lattice synthesized by doing heat treatment the precursor and chelating agent via sol-gel process. The peaks in the XRD patterns are broad, which may be due to small particle size. The variation of lattice constant with metal Substitution inevitably supports the occupancy of the metal ions into the host magnetite lattice. The changes in the lattice parameter results from the difference in the metallic ionic radii. The relationship between transition metals substitution and lattice parameter can be explained by Vegard’s law. The shift in 311 peaks is due to greater ionic radii of substituent Ag+ (1.44 A),Zn2+ (0.82 A) are greater than host Fe2+ (0.61 A).

[0028] Fig. 2 shows the FESEM micrographs of the synthesized pure magnetite and transition metal-substituted ferrite NPs. FESEM micrographs illustrate nearly spherical shaped with particle size below 30 nm distributed over the entire region, which infers fine grain growth. A clear boundary between neighboring crystallites cannot observed due to occasional agglomeration caused by magnetic interactions among NPs. particle distribution histogram for NPs indicate that the particle sizes are distributed in the range of 10 to 35 nm. The characteristic EDX spectra are shown also in Fig 2 . The traces of impurities and other elements are not identified. The observed composition ratios of metal ions (Zn, Ag) and iron to oxygen (Fe,0) are consistent with expected composition ratio. This indicates that the expected stoichiometry under preparation is well maintained in the samples that prepared using the sol-gel technique.

[0029] Fig.3 shows the M-H curves of XFe304 (x = Zn, Ag) ferrite NPs. The magnetization curves display narrow hysteresis for these compositions which showed no hysteresis and coercivity are almost found to be zero. The results that is shown in table 1 revealed that the saturation magnetization of the NPs is between 50emu/g-68 emu/g that in, while the coercivity is kept almost near zero Value with different metal substitution and all measurements reveal that magnetic saturation (Ms) of each samples are in good agreement with the other researchers results, that all these samples can show superparamagnetic behaviour.

0030] It is also clear that, these compositions exhibited narrow loops, with a behavior characteristic of soft magnetic materials for easy magnetization and demagnetization. The super exchange interactions between the metal ions of sub-lattice A and B were responsible for the magnetization. The exchange interactions between sub-lattices of soft ferrites consist of intra-sub-lattice exchange interactions (A-A) and (B-B). A-B interaction is predominant over A-A and B-B interactions.

[0031] Antimicrobial property of the Fe304, AgZnFe204 and were analyzed by treating two bacteria E. Coli and S. Auresus. The viability was assessed by the determination of clear zone of inhibition around the disc after 48-h incubation. The antimicrobial activity was compared with commercial antimicrobial agent, as a positive and negative control on the disc.

[0032] The obtained results are presented in Table 2, and the respective images inhibition zones are shown in Fig. 4

0033] It can be observed that as the different substitution of ferrite NPs, microbial cultures are changed. All NPs show good antimicrobial action against E. Coli and S. Auresus but the effect on E. coli is more than S. aureus that means ferrite NPs has more antibacterial activity on this special type of bacteria and if measure the zone of inhibition separately can find Zn ferrite NPs has the largest inhibition zones and its greater than 5 mm. Generally, getting 5mm inhibition zone diameter due to testing material represents the good antibacterial activity against to bacteria which is under testing. Several discussions are going on among the researchers about the antibacterial activity. However, the possible mechanism of antimicrobial activity for the NPs is due to:

[0034] (1) interference during cell wall synthesis;

[0035] (2) suppression during protein biosynthesis (translation);

[0036] (3) interference or disruption of transcription process; and

[0037] (4) disruption of primary metabolic pathways.

[0038] The inactivation of bacterial enzymes by the mechanism that metal ions released from nano clusters interact with the thiol groups present in bacterial enzymes which results in damage to bacterial DNA and cell death. The results revealed that the metal substituted Fe304 NPs are quite effective than the Fe304 against E. coli and S.areus. This is due to the fact that the antimicrobial activity of the metal substituted Fe304 depends on the amount and kind of metal ions released which can cause cell distortion and death of bacterial species.

[0039] Fig. 6. Shows the FESEM images of progress of metal-substituted ferrite NPs interaction with E. coli bacteria. Both the morphology and number of microscopic organisms connected to the glass surface are essentially unique in relation to those appended to the integrated progress metal-substituted ferrite NPs. The interaction (antibacterial activity) of NPs with microorganisms based on FESEM micrograph is given as XFe204 (XFe204 (X =(a)Ag, (b) Zn, (c)ZnAg. The highest antibacterial activity is observed for zinc substituted ferrite NPs. Zinc demonstrates significant growth inhibition of a broad spectrum of bacteria. The suggested mechanism for the antibacterial activity is based mainly on catalysis of formation of reactive oxygen species (ROS) from water and oxygen .

Brief Description of Drawings

[0040] Fig.1 shows XRD pattern of XFe2C>4 (X =(a)Ag, (b) Zn, (c)ZnAg) sintering at 700 °C the Gaussian fit of the peak (311 ) (inset)

[0041] Fig.2 shows FE-SEM images, particle size distribution histograms(inset) and EDS spectrograph of XFe2C>4 (XFe2C>4 (X =(a)Ag, (b) Zn, (c)ZnAg)

[0042] Fig.3 shows the room temperature M-FI curves of of XFe2C>4 (XFe2C>4 (X =(a)Ag, (b) Zn, (c)ZnAg)

[0043] Fig.4 shows zone of inhibition produced by different metal-substituted ferrite NPs against both Gram-positive and Gram-negative bacterial strains

[0044] Fig.5 shows antibacterial activities against E. coli and S. aureus of synthesized transition metal-substituted ferrite NPs XFe204 (XFe204 (X =(a)Ag, (b) Zn, (c)ZnAg).

[0045] Fig.6 shows FE-SEM images of the E. coli bacteria, XFe204 (XFe204 (X =(a)Ag, (b) Zn, (c)ZnAg). j