RU2474471C2 - Colloidal solution of silver nanoparticles, metal-polymer nanocomposite film material, methods for production thereof, bactericidal composition based on colloidal solution and bactericidal film made from metal-polymer material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used as a sterilising medium or an antibacterial component, particularly when making bactericidal liquid plaster, a component when producing materials for restoration of bones and other body tissue in restorative medicine, film material as a bactericidal, nontoxic, biodegradable coating on wounds, burns etc. The colloidal solution and film material can also be used in electronics and optoelectronic applications. The method of producing the colloidal solution of silver nanoparticles involves dissolving AgNO₃ and a stabiliser polymer - carboxymethyl chitin in concentration of 0.1-3 wt % in water and concentration of AgNO₃ 3.5-10.1 mM in carboxymethyl chitin solution, bubbling inert gas through the layer of solution and gamma-ray exposure of the solution with a dose of 2-12 kGy with reduction of silver ions to silver nanoparticles. Before bubbling, isopropyl alcohol or ethanol or ethylene glycol is added to the obtained solution. The invention also relates to a colloidal solution of silver nanoparticles obtained using said method, and a bactericidal composition based thereon. To obtain a metal-polymer nanocomposite film material from a colloidal solution of silver nanoparticles, a solution of carboxymethyl chitin in concentration of 2-4 wt % is added and the nanocomposite film material is obtained by moulding and removing water by evaporation until achieving moisture content of 10 wt %. The invention also relates to a film material obtained using said method and a bactericidal film made therefrom.

EFFECT: obtaining size- and shape-homogeneous silver nanoparticles, high bactericidal activity, especially with respect to Salmonella typhimurium and Staphilococcus aureus strains with possibility of maintaining flow of oxygen into a wound area to be healed, accelerates repair and epithelialisation processes, accelerates biodegradation of material up to full decomposition thereof on the healed surface, which enables to prevent the injurious procedure of removing the film.

7 cl, 2 tbl, 9 ex, 10 dwg

Description

The present invention relates to a colloidal solution of silver nanoparticles and metal-polymer nanocomposite film materials and methods for their preparation, as well as a bactericidal composition based on a colloidal solution and a bactericidal film from a metal-polymer material and allows to obtain silver nanoparticles of uniform size and shape included in the matrix polymer stabilizer. A bactericidal composition based on a colloidal solution of metal nanoparticles can be widely used, in particular, as a sterilizing medium or an antibacterial component in various compositions. Thus, a colloidal solution of silver nanoparticles stabilized by carboxymethylchitin, into which additives can be added if necessary, can be used for the preparation of bactericidal liquid plasters, which are used in the initial treatment of small skin lesions in everyday life and at work to prevent infection of the wound surface. Such bactericidal liquid patches are used in the form of a concentrated solution of all components or in the form of an aerosol. A bactericidal film made of a composite film material can be used as a biodegradable (absorbable) coating on wounds and burns, made in the form of a single or double layer coating. Moreover, it may be combined with other biodegradable polysaccharides (chitosan, alginate, etc.).

In addition, a colloidal solution containing silver nanoparticles can be used to create conductive inks that can be used in electronics and optoelectronic applications to produce flexible and expandable microelectrodes that transmit signals from one element of the circuit to another. Printed microelectrodes can withstand repeated bending and stretching with minimal change in their electrical properties. A metal-polymer film material containing silver nanoparticles can be used in many fields, such as optics, electronics, sensor manufacturing, and much more.

Many methods are known for producing colloidal metal particles. Depending on the conditions conducive to the formation and stabilization of metal nanoparticles in solutions, the methods for producing nanoparticles can be divided into two main groups: reverse micellar systems, where the process of reduction of metal ions into nanoparticles proceeds in the water core of the micelle, and the growing nanoparticles are surrounded by a shell of molecules of surface -active substance (surfactant) [M.Pileni The role of soft colloidal templates in controlling the size and shape of inorganic nanocrystals. Naturematerials, 2003, V.2, P. 145-150]; systems using synthetic and natural polymers as a stabilizer of nanosized particles [Wu S., B.P. Mosher, K. Lyons, T. Zeng. Reducing ability and mechanism for polyvinylpyrrolidone (PVP) in silver nanoparticles synthesis. J. Nanosci. Nanotechnol. 2010. V.10. Number 4. P.2342-2347]. The essence of the method described in [E.M. Egorova, A.A. Revina. Mechanism of the interaction of quercetin with silver ions in reverse micelles Russian Journal of Physical Chemistry A. 2003. V.77. No. 9. P.1513-1521], consists in the formation of inverted micelles of nanosized metal particles by reduction of metal ions from an aqueous solution of silver nitrate dispersed in non-polar hydrocarbon in reverse micelles of surfactants - sodium bis-2-ethylhexyl sulfosuccinate (RT aerosol). The described method of inverted micelles is widely known and allows to obtain metal nanoparticles uniform in size and shape. However, the resulting colloidal solution contains a large amount of non-polar solvent - isooctane, which significantly limits the possibility of using such systems in medicine and cosmetics. In addition, since surfactants are used as a stabilizer in such systems, the drawback of such systems is the need to overcome the incompatibility of organic colloidal solutions of nanoparticles with aqueous polymer solutions to obtain materials of various shapes (films, fibers, sponges, etc.).

To eliminate these shortcomings, synthetic and natural polymers are used as a stabilizer of metal nanoparticles. With this method of stabilizing metal nanoparticles in solution, both chemical reagents and various types of high-energy radiation, in particular gamma radiation, can be used as a reducing agent.

Among the chemical reducing agents in such systems, hydrazine, hydrogen, and borohydrides are most often used [T. Hasell, J. Yang, W. Wang, P. D. Brown, S. M. Howdle. A facile synthetic route to aqueous dispersions of silver nanoparticles Mater. Lett. 2007. V.61. Number 27. P. 4906-4910; A. Pal, S. Shah and S. Dev. Synthesis of Au, Ag and Au-Ag alloy nanoparticles in aqueous polymer solution. Col. Surf A. 2007. V.302. 1-3. P.51-57]. However, metal nanoparticles obtained by chemical reduction may be contaminated with impurities of both the starting reducing agents and toxic reaction products.

An important advantage of radiation-chemical reduction of metal-containing nanoparticles is the possibility of synthesizing metal nanoparticles with good reproducibility in solid media (e.g., polymer matrices, films) and at low temperatures, as well as obtaining the target product devoid of impurities associated with chemical reduction methods.

It is known that chitin is insoluble in conventional solvents, which limits the scope of its practical application. In addition, the N-deacetylated derivative of chitin - chitosan, dissolves in aqueous solutions only at pH less than 6.5. Therefore, for its further use in medicine and cosmetics, removal of excess acid is required, which entails a change in the shape and size of the material obtained. Unlike chitin and chitosan, their carboxymethylated derivatives, in particular carboxymethylchitin, along with low toxicity are notable for their good solubility in water, which confirms the promise of its use as a stabilizer of metal nanoparticles.

Closest to the proposed invention are a colloidal solution, a method for its preparation, a bactericidal composition based on it, a metal-polymer composite material, a method for its preparation and a bactericidal film from it described in the patent [M. S. Lee et all. Colloid solution of metal nanoparticles, metal-polymer nanocomposites and methods for preparation thereof. Patent No. US 7348365. 2008]. The essence of the method for producing a colloidal solution is to restore silver nanoparticles from its salts, including silver nitrate, in aqueous solutions in the presence of the following polymers as a stabilizer - polyvinylpyrrolidone, polyacrylonitrile, polymethylmethacrylate, polymethylacrylate, followed by bubbling through a solution of nitrogen or argon. To restore silver ions into metal nanoparticles, gamma radiation was used. According to this invention, silver nanoparticles can be obtained both in the form of a colloidal solution, and in the form of a metal-polymer solid composite paste or thin film. A metal-polymer material is obtained by dissolving a silver salt and a stabilizing polymer in water, sparging through a solution of nitrogen or argon, and gamma radiation. The resulting composition and film are bactericidal. The disadvantages of the prototype should include the fact that the polymers used are not among the biodegradable systems, which narrows the scope of their application in the biomedical field. In addition, the proposed range of polymers does not allow them to obtain products of various shapes, namely fibers, sponges, hydrogels, etc.

The problem to which the present invention is directed, is to obtain a non-toxic colloidal solution of silver nanoparticles and based on it a bactericidal composition, a biodegradable composite film material and a bactericidal film based on it containing silver nanoparticles, uniform in size and shape, the use of which in surgery for treatment wounds and burns will allow:

- to provide a prolonged antimicrobial effect and avoid the risk of infection of the wound surface with pathogenic microflora;

- maintain the supply of oxygen to the wound area necessary for the healing process;

- accelerate the processes of regeneration and epithelization;

- eliminate the need for a traumatic film removal procedure due to the rather rapid biodegradation of the film up to its complete decomposition on the healing surface.

The solution to the above problem is achieved by the use of non-toxic [S. Tokura, S. Nishimura, N. Sakairi, N. Nishi. Biological activities of biodegradable polysaccharide. Macromol. Symp. 1996. V.101. P.389-96], biodegradable [P.A. Sandford In: G. S.jak-Braek, T. Anthonsen, P. A. Sandford, editors. Chitin and chitosan. London: Elsevier Applied Science. 1989. p.51-69] a water-soluble derivative of chitin - carboxymethylchitin - as a polymer stabilizer matrix for the synthesis of silver nanoparticles, as well as a film-forming material. Carboxymethylchitin can be obtained from chitin using a one-step method [G.A. Vikhoreva, D.Yu. Gladyshev, M.R. Bazt, V.V. Barkov, L.S. Galbraich. The effect of activating additives on the structure and reactivity of chitin and chitosan and the synthesis of their carboxymethylated derivatives. Cellulose Chem. Technol. 1992. V.26. No. 6. P.663-674]. It is known that carboxymethylchitin is used as biosensors [H.Y. Xie, J. G. Liang, Y. Liu, Z. L. Zhang, D. W. Pang, Z. K. He et al. Preparation and characterization of overcoated II-VI quantum dots. J. Nanosci. Nanotechnol. 2005. V.5. No. 6. P.880-886], a drug carrier [S. Tokura, Y. Miura, M. Johmen, N. Nishi, S. I. Nishimura. Induction of drug specific antibody and the controlled release of drug by 6-O-carboxymethyl-chitin. J. Control. Release 1994. 28. No. 1-3. P.235-241], implants in tissue engineering for bone repair [S. Tokura, H. Tamura O-carboxymethyl-chitin concentration in granulocytes during bone repair. Biomacromolecules 2001. V.2. No. 2. P.417-421], etc.

In the method for producing a colloidal solution of silver nanoparticles, including dissolving AgNO ₃ silver nitrate and a stabilizing polymer in water, bubbling an inert gas through a layer of the resulting solution and subsequent gamma irradiation of the solution with the reduction of silver ions into silver nanoparticles, carboxymethylchitin is used as a stabilizing polymer when its concentration in an aqueous solution of 0.1-3 wt.% the dissolution of AgNO _{3 is} carried out to a concentration of 3.5-10.1 mm in a solution of carboxymethylchitin, and the specified gamma irradiation with a dose of 2-12 kGy.

Before bubbling, alcohol can be added to the resulting solution: isopropyl alcohol or ethanol, or ethylene glycol.

A colloidal solution of silver nanoparticles obtained by this method is also claimed.

A bactericidal composition based on a colloidal solution is also claimed.

In the method for producing a metal-polymer nanocomposite film material from a colloidal solution of silver nanoparticles, a solution of carboxymethylchitin in water of a concentration of 2-4 wt.% Is added to the obtained solution of silver nanoparticles, and a film material is obtained by molding and removing water by evaporation to achieve a moisture content of 10 wt.%.

Also claimed is a metal-polymer nanocomposite film material obtained by this method.

A bactericidal film of a metal-polymer nanocomposite film material is also claimed.

To obtain a colloidal solution of silver nanoparticles, a salt, silver nitrate AgNO _3, and a water-soluble polymer carboxymethylchitin with a weight average molecular weight of Mw 50,000-450000, used as a stabilizer of silver nanoparticles, are used in water.

According to the present invention, a solution of the polymer in water is used in concentrations from 0.1-3 wt.%. When using lower concentrations of less than 0.1 wt.%, The stabilizing effect of the polymer was significantly reduced, so, in particular, at a concentration of 0.05 wt.% The formation of silver nanoparticles was not observed. The use of higher concentrations of more than 3 wt.%, Led to undesirable association processes and the formation of larger particles. Then, an alcohol, such as isopropyl alcohol, ethanol, or ethylene glycol, is added to the polymer solution. When using any of the listed alcohols, the results do not significantly change. It is known that alcohols serve as interceptors of hydroxyl radicals generated by gamma radiation.

The process of forming silver nanoparticles consists in the generation of solvated electrons in a solvent (in water) under the action of gamma radiation and their subsequent interaction with silver ions in solution. The presence of a stabilizing polymer in such systems prevents unwanted agglomeration and an increase in the size of the resulting silver nanoparticles. Under radiation exposure in a solution not only electrons, but also radicals can form. In order to inactivate the radicals, radical quenchers, for example alcohols, are used. Oxygen present in the reaction medium is removed by purging (sparging) with argon or nitrogen to prevent side oxidation reactions.

To obtain a colloidal solution of silver nanoparticles, an aqueous solution of silver nitrate is taken so that the concentration of silver nitrate in the carboxymethylchitin solution is 3.5-10.1 mM. If the concentration of silver nitrate AgNO _{3 is} taken less than the specified interval, the number of formed nanoparticles is substantially reduced. If the concentration of silver nitrate AgNO _{3 is} taken above the specified interval, the formation of larger silver nanoparticles and even the formation of a precipitate are observed.

The resulting solution containing carboxymethylchitin and silver nitrate at a concentration of 3.5-10.1 mmol in a carboxymethylchitin solution was purged with argon for 1.5-3 hours and carefully sealed. Nitrogen and helium can be used as an inert gas with the same result.

Then the resulting solution is subjected to gamma radiation in a dose of 2-12 kGy. The result is a colloidal solution of uniformly shaped silver nanoparticles with a particle size of 1-5 nm.

The bactericidal composition is a colloidal solution of silver nanoparticles into which, if necessary, additives, for example rosin, glycerin, etc. can be added.

The metal-polymer film composite material is obtained by adding an aqueous solution of carboxymethylchitin with a concentration of 2.0-4.0 wt.% To the colloidal solution of silver nanoparticles obtained after gamma irradiation. The resulting solution was thoroughly mixed using a magnetic stirrer for 10-15 minutes. Then, metal-polymer composite film materials are formed from the resulting solution by dry method by removing water by evaporation to a moisture content of 10 wt.%.

For a more detailed acquaintance with the invention, specific examples are given below, which serve to illustrate but do not exhaust all the possibilities of obtaining and using the systems described in this invention.

Example 1. Obtaining a colloidal solution of nanostructured silver particles, in which carboxymethylchitin is used as a stabilizer polymer

To 3 ml of a 0.5 wt.% Solution of carboxymethylchitin in water (Mw = 70,000), 0.05 ml of isopropyl alcohol and an aqueous solution of silver nitrate AgNO ₃ are added to a concentration of 3.5 mmol in a solution of carboxymethylchitin. The resulting solution containing carboxymethylchitin and silver nitrate was purged with argon for 1.5 hours and carefully sealed. Then the resulting solution is subjected to radiation at a dose of 2 kGy.

Monitoring the formation of a colloidal solution of silver nanoparticles and assessing their stability is carried out by spectrophotomeric method by changing the optical density at the maximum of the plasma absorption band of the resulting silver nanoparticles in the region of 420 nm (Figure 1). The size of the formed silver nanoparticles and their shape are examined by transmission electron microscopy (TEM). The colloidal solution of silver nanoparticles contains particles uniform in shape and size with an average particle diameter of 2-3 nm (Figure 2).

Example 2

A colloidal solution of silver nanoparticles is obtained according to the method described in example 1, while increasing the radiation dose to 10 kGy.

From a comparison of the spectra in FIGS. 3 and 1, it follows that with an increase in the irradiation dose of the reaction mixture from 2 to 10 kGy, the optical density at the maximum absorption band of silver nanoparticles increases, which indicates an increase in the number of silver nanoparticles formed. TEM results showed that under these conditions there is a slight increase in the size of the formed nanoparticles, however, the average particle diameter did not exceed 10 nm (Figure 4).

Example 3

A colloidal solution of silver nanoparticles is obtained according to the method described in example 1, while the concentration of silver nitrate AgNO ₃ in a solution of carboxymethylchitin is 10.1 mm.

From a comparison of examples 3 (FIG. 5) and 1 (FIG. 1), it is seen that with an increase in the amount of silver nitrate, the optical density at the maximum of the absorption band of silver nanoparticles increases, and hence the amount of silver nanoparticles formed. However, the size of the resulting nanoparticles increases slightly, and their average diameter is 3-5 nm (Fig.6).

Example 4. The effect of low polymer concentrations on the formation and formation of silver nanoparticles

To 3 ml of a 0.05 wt.% Solution of carboxymethylchitin in water (M _w = 70,000), 0.05 ml of isopropyl alcohol and an aqueous solution of AgNO ₃ silver nitrate are added to a concentration of 6.8 mM in a solution of carboxymethylchitin. The resulting solution containing carboxymethylchitin and silver nitrate was purged with argon for 1.5 hours and carefully sealed. Then the resulting solution is subjected to radiation at a dose of 2 kGy.

From the spectral data shown in (Fig.7), it follows that at a low polymer concentration the formation of silver nanoparticles in solution practically does not occur due to the fact that under these conditions an effective concentration of the stabilizing polymer was not achieved.

Example 5. The effect of polymer concentration on the formation and formation of silver nanoparticles

To 3 ml of a 1.0 wt.% Solution of carboxymethylchitin in water (M _w = 70,000), 0.05 ml of isopropyl alcohol and an aqueous solution of silver nitrate AgNO ₃ are added to a concentration of 6.8 mM in a solution of carboxymethylchitin. The resulting solution containing carboxymethylchitin and silver nitrate was purged with argon for 1.5 hours and carefully sealed. Then the resulting solution is subjected to radiation at a dose of 10 kGy.

As can be seen from the comparison of Fig. 8 and Fig. 1, with an increase in the polymer concentration, there is a slight decrease in the optical density at the maximum of the absorption band and, consequently, in the number of nanoparticles formed. Figure 9 shows the TEM data.

Example 6. The study of the stability of a colloidal solution of silver nanoparticles

To study the stability of a colloidal solution of silver nanoparticles, a nanoparticle solution obtained by the method described in example 1 is used. The nanoparticles are incubated for 12 months at room temperature and then examined using the TEM method. As can be seen from the comparison of microphotographs in figure 1 and figure 10, during this period there is a slight increase in particle size, while the particle diameter does not exceed 10 nm.

Example 7. Obtaining a film composite material based on carboxymethylchitin and silver nanoparticles

In order to obtain a metal-polymer film composite material, a colloidal solution of silver nanoparticles obtained according to Example 5 is used. To 1 ml of the obtained colloidal solution of silver nanoparticles, 1 ml of an aqueous 2.0 wt.% Solution of carboxymethylchitin is added. The resulting solution was thoroughly mixed using a magnetic stirrer for 15 minutes and then dry-formed metal-polymer composite film material by removing water by evaporation to a moisture content of 10 wt.%.

Example 8. The study of the bactericidal activity of a colloidal solution of silver nanoparticles

The antimicrobial properties of the studied samples are evaluated by the zone of inhibition of growth of pathogenic microbes, which clearly stands out against the background of continuous microbial growth in nutrient media. The size of the zone of inhibition determines the degree of sensitivity of the microbe to the antimicrobial substance. The measured diameter of the zone should pass through the center of the disk.

As test cultures used strains of gram-negative microorganisms - Salmonella typhimurium 79 and gram-positive - Staphylococcus aureus ATCC 6538Р, obtained from the collection of the State Research Institute of Standardization and Control of Medical and Biological Preparations named after L.A. Tarasevich.

For cultivation of microorganisms with a concentration of 10 ⁴ CFU / ml, culture media XLD agar (xylose lysin desoxycholate agar-xylose-lysine-deoxycholate agar) from Merck (USA) for Salmonella typhimurium and Baird-Parker type agar for Staphylococcus aureus (LLC "Biocompas-S", Russia).

There are certain correlations between the degree of sensitivity of the microbe to the test sample and the size of the diameter of the inhibition zone. An area with a diameter of up to 10 mm or a complete absence of growth retardation indicates the resistance of the microbe to this substance. A zone with a diameter of more than 15 mm indicates that the microorganism is sensitive to an antimicrobial drug, and a zone of more than 25 mm indicates a high sensitivity to an antimicrobial drug [A.S. Labinskaya. Microbiology with the technique of microbiological research. M .: Medicine, 1978, 394 p.].

The results of the study of the antimicrobial activity of the colloidal solution obtained in example 1, which was diluted with distilled water to achieve a concentration of colloidal solution of 0.5 wt.%, 0.25 wt.% And 0.17 wt.%, Are shown in table 1.

Table 1. Antimicrobial activity of a colloidal solution of various concentrations in relation to the studied test cultures of microorganisms Test culture strain dose Test sample The zone of growth inhibition of microorganisms, mm Salmonella typhimurium 79 10 ⁴ CFU / ml Source culture (control) No zone 0.50 wt.% Colloidal solution 33,2 0.25 wt.% Colloidal solution 30,2 0.17 wt.% Colloidal solution 28.5 Staphylococcus aureus 6538-P
10 ⁴ CFU / ml Source culture (control) No zone 0.50 wt.% Colloidal solution 60.0 0.25 wt.% Colloidal solution 37.0 0.17 wt.% Colloidal solution 34.8

It can be seen from the presented data that the colloidal solution exhibits a strong bactericidal effect with respect to both gram-positive and gram-negative microorganism strains, and this effect persists when the colloidal solution is diluted 2 and 3 times.

Example 9. The study of the bactericidal activity of a film composite material based on carboxymethylchitin and silver nanoparticles

The bactericidal effect of silver nanoparticles in films from a chitin derivative is studied on international strains of Salmonella typhimurium TMLR65 and Staphylococcus aureus Wood-46.

The cultivation of the Salmonella strain is carried out on Merck (USA), XLD (xylose-lysin-desoxycholat) agar from Salck, for Salmonella typhimurium and Baird-Parker type agar for Staphylococcus aureus (Biocompas-S LLC, Russia) for 18-20 hours at 37 ° C.

To identify salmonella and staphylococcus, biochemical tests and special media are used. Bacterial cultures in the logarithmic phase are obtained by growing an aliquot of the overnight culture in the same broth (culture to broth ratio 1:10) while joking (170 rpm) for 5 hours at 37 ° C. Next, prepare suspensions of bacteria with a concentration of 10 ³ and 10 ⁵ CFU / ml in sterile broth.

According to the method used, a suspension of cultures (test strains (0.05 ml) in sterile broth in the required concentration) is applied to the surface of sterile glass Petri dishes, which is then dried to 1 / 2-1 / 3 of the original volume. Next, using eye tweezers, a fragment of a cut film (1/4 part) is coated with a drop of a suspension of bacteria and incubated for 1 to 24 hours at a temperature of 30 ° C. Then, a drop (0.05 ml) of the sterile broth is applied to the film, resuspended in the broth, dilutions are prepared in the same broth, followed by their plating on plates with nutrient medium. After incubation, the number of grown colonies is counted and, in comparison with their number in the untreated culture, the presence or absence of bactericidal action is evaluated.

The results of the study of the antimicrobial activity of films of carboxymethylchitin (sample A), and composite films of carboxymethylchitin with silver nanoparticles (sample C) obtained in example 7 are shown in table 2.

table 2 Dynamics of the effect of carboxymethylchitin films containing silver nanoparticles on the number of cells of Salmonella typhimurium and Staphilococcus strains Test strain, dose Test sample lg number of living bacteria in the studied films at time intervals (h) 3.0 24.0 Salmonella typhimurium 79 10 ⁵ CFU / ml Source culture (control) 5.15 5.15 Film Sample A 4.26 3.69 Sample film C 0 0 Staphilococcus aureus 6538-P
10 ⁵ CFU / ml Source culture (control) 5.05 5.05 Film Sample A 4.78 4.38 Film Sample C 0 0 Salmonella typhimurium 79
10 ³ CFU / ml Source culture (control) 3.02 3.02 Film Sample A 2.19 1.75 Film Sample C 0 0 Staphilococcus aureus 6538-P 10 ³ CFU / ml Source culture (control) 3.10 3.10 Film Sample A 2.98 2.19 Film Sample C 0 0

From the presented data it is seen that a short contact of the film C with microorganisms within 3 hours leads to almost complete destruction of the test culture, both gram-positive and gram-negative microbes. This indicates the universal nature of the antimicrobial (bactericidal) action of composite films based on carboxymethylchitin and silver nanoparticles. A film of carboxymethylchitin, which did not contain silver nanoparticles, exerted a bacteriostatic effect, slowing the growth of microorganisms. Thus, the obtained composite films exhibit a strong bactericidal effect with respect to the strains of Salmonella typhimurium and Staphilococcus aureus at a concentration of test cultures in both 10 ³ and 10 ⁵ CFU / ml.

Claims (7)

1. A method of obtaining a colloidal solution of silver nanoparticles, comprising dissolving silver nitrate AgNO ₃ and a stabilizing polymer in water, bubbling an inert gas through a layer of the resulting solution and subsequent gamma irradiation of the solution with the reduction of silver ions into silver nanoparticles, characterized in that as a polymer -stabilizer carboxymethylchitin used at a concentration in the aqueous solution of 0.1-3 wt.%, the dissolution is carried out until AgNO ₃ concentration 3,5-10,1 carboxymethylchitin mM solution, and said gamma-irradiation s - a dose of 2-12 kGy. 2. The method according to claim 1, characterized in that before bubbling, alcohol is added to the resulting solution: isopropyl alcohol, or ethanol, or ethylene glycol. 3. A colloidal solution of silver nanoparticles obtained by the method according to claim 1. 4. The bactericidal composition based on a colloidal solution of silver nanoparticles according to claim 3. 5. A method of producing a metal-polymer nanocomposite film material from a colloidal solution of silver nanoparticles, characterized in that the solution obtained in claim 1 is used as a colloidal solution of silver nanoparticles, followed by the addition of a solution of carboxymethylchitin in water at a concentration of 2-4 wt. % and obtaining a metal-polymer nanocomposite film material by molding and removing water by evaporation to a moisture content of 10 wt.%. 6. The metal-polymer nanocomposite film material obtained by the method according to claim 5. 7. The bactericidal film of material according to claim 6.

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