KR20180000884A - Gelatin-polyurethane nanofiber comprising silver nanoparticles - Google Patents

Abstract

The present invention relates to a gelatin-polyurethane nanofiber containing silver nanoparticles, a production method thereof, and a wound dressing material containing the same. By containing the silver nanoparticles, the gelatin-polyurethane nanofiber exhibits outstanding antibacterial functions and thus can be useful as antibacterial nanofibers. The gelatin-polyurethane nanofiber of the present invention does not cause immune responses owing to biocompatibility, exhibits excellent mechanical strength, and is easily attached to cells owing to high hydrophilicity, thereby being applied as excellent wound dressing materials.

Description

Gelatin-polyurethane nanofiber < / RTI > nanoparticles < RTI ID = 0.0 > nanoparticles &

The present invention relates to a gelatin-polyurethane nanofiber comprising silver nanoparticles and a process for producing the same.

Dressing is a method used to improve the speed of healing by covering the wound surface, which is a skin defect area caused by burns, wound, pressure sores, and trauma. In the dressing method, a dry dressing method for drying a wound surface by using gauze or the like has been generalized. However, in 1962 Winter, Wet dressing has been developed and released since the announcement that it is more than twice as fast as the environment, and there are various ways of treating wounds.

The conditions required for the wet dressing material include a wet environment composition in which the epithelial cells can smoothly spread the wound surface, a prevention of infection which can prevent the bacterial invasion from the outside and proliferation because of the rapid growth of the bacteria in the wet environment, And a protective action that can prevent damage due to external physical impact.

On the other hand, according to recent reports, resistance to bacteria caused by abuse of various antibiotics is very serious. As a representative example, MRSA (Methicillin Resistant Staphylococcus Aureus) or VRE (Vancomycin-resistant enterococcus) is a pathogenic bacterium resistant to antibiotics, and most of them appear as skin infections. Surgical patients, elderly people, immune system If this weak person develops into bloodstream infections, bone infections, pneumonia, meningitis, etc., it can have fatal consequences. More than one-third of the population has bacteria such as staphylococci in the skin and nasal mucosa. Since these bacteria are contagious to other people, they are more likely to be infected with such bacteria if they are injured by burns, wounds or trauma . However, if these bacteria are resistant to antibiotics, they can cause considerable problems in wound healing.

In this connection, a dressing product using silver (Ag) which provides a wide range of antibacterial and antifungal effects has been developed. Silver is particularly excellent in antibacterial action against bacteria and viruses in the case of nano-sized particles, and exhibits an excellent effect on anti-allergy and environmental hormone inhibition. In addition, silver nanoparticles are also known as substances that do not cause any adverse effects on the human body. The silver nanoparticles in the form of colloids can easily penetrate into the cell of bacterial and viral bacteria, stop the enzyme action, inhibit cell wall breakage and metabolism of the bacteria, and thus can sterilize various bacteria, viruses and allergic diseases . Colloidal silver in aqueous solution is an FDA approved antibiotic and is used in actual clinical applications such as cotton or bandages because of its scientific evidence of its efficacy in burns, infections, inflammation and other microbial infections.

Techniques have been provided for producing antimicrobial nanomaterials or fibers using the properties of such silver nanoparticles. For example, Korean Patent Laid-Open Publication No. 10-2006-0003233 discloses a method for bonding nano silver to gauze using a water-soluble starch or a three-component hot melt type main component comprising an ethylene-vinyl acetate copolymer, a tackifier resin and a wax Process. Korean Patent Laid-Open Publication No. 10-2005-0075905 discloses a method of dispersing silver particles having a size of 20 to 70 nm in the island component of a sea-island composite fiber to chemically elute the silver particles, Lt; RTI ID = 0.0 > fiber. ≪ / RTI >

Korean Patent Publication No. 10-2006-0003233 Korean Patent Publication No. 10-2005-0075905

It is an object of the present invention to provide a gelatin-polyurethane nanofiber comprising silver nanoparticles and a method for producing the same.

Another object of the present invention is to provide a wound dressing material comprising the nanofibers.

In one aspect of the present invention, the present invention provides a gelatin-polyurethane nanofiber comprising silver nanoparticles.

In the present invention, the gelatin-polyurethane nanofiber refers to a nanofiber in which a gelatin fiber strand and a polyurethane fiber strand are mixed.

In the present invention, the silver nanoparticles may be 100 nm to 5 nm, preferably 8 nm to 22 nm, and more preferably 11 nm to 15 nm.

The nanofibers can be obtained commercially or can be obtained by known methods, preferably by reducing silver nitrate, and more preferably by reducing silver nitrate (DMF).

Reduction of silver nitrate using DMF is advantageous in that it is simple and easy to obtain silver nanoparticles and does not generate gas, as compared with the use of a common chemical reducing agent.

In the present invention, the gelatin-polyurethane nanofibers can be produced by electrospinning, preferably by co-electrospinning.

In the present invention, the electrospinning may be carried out by a method known in the art. For example, the spinning solution may be connected to the electrospinning nozzle using a feeding device, and a high voltage generating device may be used between the nozzle and the current collector It can be carried out by forming a high electric field system. The size of the electric field is related to the distance between the nozzle and the current collector, and the relationship between them is used in combination to facilitate electrospinning. As the electrospinning device to be used at this time, those conventionally used in this field can be used.

The double-electrospinning is a method of simultaneously radiating the polymer from separate nozzles, and the process of dual-electrospinning is illustrated in FIG. In the case of producing gelatin-polyurethane nanofibers by double-emissive irradiation, silver nanoparticles can be contained only in the polyurethane strand. Silver nanoparticles can be prevented from being released rapidly when the nanoparticles are contained only in the polyurethane strands.

Accordingly, in a preferred embodiment of the present invention, there is provided a gelatin-polyurethane nanofiber in which silver nanoparticles are present only in polyurethane fibers. The nanofibers can release silver nanoparticles continuously.

In one specific embodiment of the present invention, silver nitrate is dissolved in DMF solvent, and the mixed solution and the polyurethane solution are mixed. Then, the silver nanoparticles and the polyurethane mixed solution and the separate gelatin solution were double-electrospun to prepare nanofibers.

In a specific example of the present invention, the hydrophilicity of the gelatin-polyurethane nanofiber prepared as described above was confirmed. As a result, the nanofiber of the present invention showed better wettability than the polyurethane alone fiber.

Since the nanofiber of the present invention contains gelatin and is excellent in hydrophilicity, it can exhibit an excellent effect on cell adhesion and migration.

In addition, the gelatin-polyurethane nanofiber of the present invention is biocompatible. In the present invention, biocompatibility means that the gelatin-polyurethane nanofiber of the present invention does not induce or less induce an immune response, or the gelatin- Or integrate with a particular cell type or tissue.

In addition, the gelatin-polyurethane nanofiber of the present invention has excellent mechanical strength.

The nanofibers of the present invention also contain silver nanoparticles exhibiting antimicrobial activity, and thus are excellent in antimicrobial activity.

In the present invention, the term "antimicrobial" includes not only inhibiting the growth of pathogenic microorganisms such as bacteria and fungi but also sterilizing by inhibiting its survival. The chitosan and polyurethane nanofibers containing sulfadiazine silver of the present invention can be used for antibacterial treatment of all pathogenic microorganisms around the living environment. For example, Candida, Cryptococcus, Aspergillus, Trichophyton, Trichomonas, Chaetomium, Gliocladium, Aureobasidium, Penicillium, Such as Rhizopus, Cladosporium, Mucor, Pullularia, Trichoderma, Fusarium, Myrothecium, Memnoniella, ) And fungi such as Escherichia, Bacillus, Pseudomonas, Chetonium, Staphylococcus, Klebsiella Legionella, Salmonella, (Salmonella), Vibrio (V ibrio, Rickettsia, Porphyromonas, Prevotella, Aggregatibacter, and the like, but are not limited thereto.

Preferably, the gelatin-polyurethane nanofibers comprising the silver nanoparticles of the present invention exhibit antimicrobial activity against periodontal disease bacteria, more preferably Porphyromonas gingivalis , Prevotella intermedia ), And Aggregatibacter actinomycetemcomitans . ≪ / RTI >

In a specific embodiment of the present invention, the antimicrobial activity of the nanofibers of the present invention was confirmed in vitro . As a result, it was confirmed that the antimicrobial activity was increased depending on the content of silver nanoparticles.

The present invention provides a wound dressing material comprising gelatin-polyurethane nanofibers comprising silver nanoparticles.

The silver nanoparticles and the gelatin-polyurethane nanofibers are as described above.

The nanofiber of the present invention has a wide range of antibacterial activity due to the inclusion of silver nanoparticles and at the same time has high hydrophilicity including gelatin and exhibits excellent mechanical strength and can be firmly fixed on the wound surface, It can be utilized as a material for dressing.

In addition, the wound dressing material of the present invention exhibits antibacterial activity against periodontal disease causing bacteria.

Thus, in one preferred embodiment of the present invention, an oral wound dressing material is provided.

The wound dressing material of the present invention may be in the form of, for example, a film, a sheet, a nonwoven fabric, a foam, a rope, a pellet, a powder, a fabric or the like, but is not limited thereto.

Since the nanofiber of the present invention contains gelatin and is excellent in hydrophilicity, it can exhibit an excellent effect on cell adhesion and migration. Gelatin can also provide a hemostatic action by carbodiimide hydrochloride (EDC) crosslinking.

Therefore, the dressing material comprising the nanofibers of the present invention can act as an excellent wound dressing.

In addition,

1) dissolving silver nitrate in a solvent of N, N-dimethylformamide (DMF);

2) mixing the solution prepared in step 1) with a solution containing polyurethane; And

3) filling the solution prepared in step 2) and the solution containing gelatin into different syringes and electrospinning simultaneously

The present invention provides a method for producing a gelatin-polyurethane nanofiber comprising silver nanoparticles.

The silver nanoparticles and the gelatin-polyurethane nanofibers are as described above.

The step 1) is a step of reducing silver nitrate to form silver nanoparticles. In step 1), silver nitrate may be dissolved in DMF at a concentration of 0.1 to 10 moles, preferably from 0.5 moles to. 5 < / RTI > Also, the step 1) may be carried out at a temperature of 80 ° C to 120 ° C, more preferably 90 ° C to 110 ° C.

The step 2) is a step of mixing the silver nanoparticle solution prepared in the step 1) with the polyurethane solution to produce a polyurethane strand in which the silver nanoparticles are present. The polyurethane solution may be any single or mixed organic solvent containing DMF as a solvent. The concentration of the polyurethane solution may be from 2 wt.% To 20 wt.%, And preferably from 5 wt.% To 12 wt.%. In step 2), the mixing ratio of the silver nanoparticles and the polyurethane solution may be 1: 5 to 1: 0.1, preferably 1: 2.5 to 1: 0.2, more preferably 1: 1 to 1: 0.3 Lt; / RTI >

If the amount of silver nanoparticles is too large, silver can change the surface tension and viscosity of the electrospinning solvent, which can cause the spray ejection to collapse in the electrospinning process, resulting in the formation of beads.

Step 3) is a step of preparing nanofibers in which silver nanoparticle-containing polyurethane solution is filled in a separate syringe and electrospun at the same time so that only nanoparticles of silver nanoparticles exist in the polyurethane strand. In the step 3), the gelatin solution may be any organic solvent, preferably 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent . The concentration of the gelatin solution may be from 2 wt.% To 20 wt.%, Preferably from 5 wt.% To 12 wt.%. The voltage in the electrospinning of step 3) may be 10 kV to 100 kV, preferably 10 kV to 30 kV. Further, the distance between the needle tip and the current collector in the electrospinning may be 10 cm to 20 cm, and preferably 12 cm to 18 cm.

The gelatin-polyurethane nanofiber of the present invention contains silver nanoparticles and exhibits excellent antimicrobial properties, and thus can be usefully used as an antibacterial nanofiber.

In addition, since the gelatin-polyurethane nanofiber of the present invention is biocompatible, it does not induce an immune response, is excellent in mechanical strength, and has high hydrophilicity and easily adheres to cells. Therefore, it can be used as an excellent wound dressing, .

Figure 1 is a schematic representation of a process for preparing the gelatin-polyurethane nanofibers of the present invention by co-electrospinning.
Fig. 2 shows the observation of silver nanoparticles synthesized in the examples using a transmission electron microscope (TEM).
FIG. 3 is a graph showing the particle size distribution of silver nanoparticles synthesized in the examples analyzed by dynamic light scattering (DLS).
4 is a graph showing ultraviolet-visible light spectrophotometric analysis of a DMF solution containing silver nanoparticles synthesized in the examples.
FIG. 5 shows TEM images of the nanofibers prepared in Examples. FIG. 5 (a) shows EN-1, FIG. 5 shows EN-2, ) Is the observation of EN-4.
6 shows EN-1, (b), EN-2, (c), EN-1, and (b) show the polyurethane strands of the nanofibers prepared in the examples by transmission electron microscopy 3.
FIG. 7 is a graph showing the results of analysis of components of nanofibers by energy dispersive X-ray spectroscopy (EDS), wherein (a) is polyurethane alone fiber, (b) is gelatin alone fiber, Urethane alone fiber.
FIG. 8 is a graph showing the results of infrared spectroscopic analysis of nanofibers, wherein (a) is a polyurethane single fiber, (b) is a gelatin single fiber, and (c) .
9 is a graph comparing and measuring the amounts of water absorption of the polyurethane alone fibers (PU EN) and EN-1 prepared in the examples.
Fig. 10 is a photograph showing a state in which a polyurethane single fiber and EN-1 prepared in Example are immersed in a cell culture medium, wherein (a) is a polyurethane single fiber, and (b) corresponds to EN-1.
11 is a measurement of water contact angle of polyurethane alone fiber (PU EN) and EN-1 prepared in Example.
FIG. 12 is a graph showing the thermal resolution of the nanofibers prepared in the examples by thermogravimetric analysis (TGA). The graphs inside show the differences in the decrease in EN-1 and EN-4 at 760 ° C. will be.
FIG. 13 is a graph showing the results of measurement of the silver ion release rate of the nanofibers prepared in the examples using an inductively coupled plasma mass spectrometer (ICP-MS).
Fig. 14 is a graph showing the results of measurement of the Porphyromonas gingivalis in vitro . < / RTI >
Fig. 15 is a graph showing the relationship between the nanofiber prevotella This is a graph showing the results of in vitro antibacterial test on intermedia .
16 is a graph showing in vitro antibacterial test results of aggregatibacter actinomycetemcomitans of nanofibers prepared in the examples.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided to further understand the present invention, and the present invention is not limited by the examples.

Experimental material

Polyurethane (Bionate 75A) was purchased from Resomer (Ingelheim, Germany). Tetrahydrofuran (99.5%) was purchased from JUNSEI (JUNSEI CHEMICAL Co. Ltd., Japan). Ethanol (99.9%) was purchased from DaeJung (Chemical & Metals Co. LTD. Korea). N-dimethylformamide (anhydrous, 99.8%) and (3-aminopropyl) trimethoxysilane (APS, 97% - purchased from Aldrich (St. Louis, MO). 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide were dissolved in TCI (Tokyo Kasie Kogyo Co. Ltd., Japan). Porphyromonas gingivalis W83 It was supplied by Nagasaki University Graduate School of Biomedical Sciences. Prevotella intermedia ATCC49046 and Aggregatibacter actinomycetemcomitans Y4 (ATCC 43718) were obtained from the American Type Culture Collection (American Type Culture Collection, Manassas, VA, USA). Brucella broth and brain heart infusion (BHI) broth were purchased from Difco Laboratories (Detroit, MI, USA). Hemin and vitamin K ₁ were purchased from Sigma-Aldrich (St. Louis, MO, USA). The blood of Talibbreen is MEDEXX Co., Ltd. (Korea). Deionized-distilled water was produced in an ultrapure water system (Puris Ro800; Bio Lab Tech., Korea). All chemical solvents used were used without further purification.

< Example > Preparation of gelatin-polyurethane nanofiber containing nanoparticles

Gelatin-polyurethane nanofibers containing silver nanoparticles were prepared using the dual-electrospinning scheme illustrated in FIG.

1. Synthesis of silver nanoparticles

Silver nanoparticles were synthesized directly in N, N-dimethylformamide (DMF) solvent, an electrospinning (ELSP) solvent, in order to use the nanoparticles for the production of nanofibers.

In order to produce silver nanoparticles in an electrospinning solvent, particles were synthesized directly in DMF using aminopropyltriethoxysilane (APS) as a capping agent.

100 mM silver nitrate was dissolved in 100 ml DMF and stirred at 100 占 폚. After dissolving all the silver nitrate, 1.75 mL of 100 mL APS was poured into the DMF solution in which the silver nanoparticles were dissolved and kept for 24 hours. The solution was then cooled to room temperature and filtered to remove impurities. The solvent was shaded and stored at room temperature. To prevent aggregation, the nanoparticle slurry was used as soon as possible.

2. Preparation of gelatin-polyurethane nanofiber

The gelatin composition was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solvent to make 8 wt.%. The polyurethane composition was dissolved in DMF / tetrahydrofuran (THF) (5: 5) solvent to make 8 wt.%. (EN-1), 3: 7 (EN-2), and 7: 3 (EN-3) with the solvent containing silver nanoparticles prepared above in order to control the amount of silver nanoparticles And 10: 0 (EN-4). The exact amount of silver nanoparticles added was confirmed in Experimental Example 4.

After preparing the electrospinning solution, the polymer solution was added to a luer-lock syringe equipped with a blunt metal needle (20G, Kovax-needle, Korea Vaccine Co., Ltd., Korea) Loaded, and electrospun to a rotating mandrel covered with aluminum foil. The conditions were as follows, and the two solutions were equally electrospun at the same time.

Device: High-voltage DC power supply (Nano NC, Korea)

Voltage: 20 kV

Radiation rate: 1 mL / h

Distance between needle tip and collector: 15 cm

To remove all residual solvent, the resulting nanofibers were dried in vacuo overnight. To crosslink the nanofibers, the dried sample was immersed in an ethanol solution containing 50 mM carbodiimide hydrochloride (EDC) and 25 mM N-hydroxysuccinimide (NHS) for 24 hours and gently shaken. Then, it was washed sequentially with ethanol and deionized-distilled water (DDW). The resulting nanofibers were freeze-dried.

< Experimental Example  1> Characterization of nanoparticles

The characteristics of the silver nanoparticles synthesized in the examples were confirmed.

1-1. Transmission electron microscope ( TEM ) observe

Silver nanoparticles were observed using a transmission electron microscope (TEM) (H-7100, Hitachi, Japan) at an accelerating voltage of 100 kV at room temperature.

As a result, a nano-sized particle shape was observed in the DMF solution as shown in Fig. Thus, it can be seen that silver nanoparticles are successfully formed in the DMF solution.

1-2. Dynamic light scattering (DLS) analysis

The size distribution of silver nanoparticles was confirmed using a Malvern DLS instrument (Nano-ZS, Malvern Instruments, Malvern, UK).

As a result, as shown in FIG. 3, the size frequency distribution of the silver nanoparticles ranged from 8 nm to 22 nm, and it was confirmed that the average diameter was 13 +/- 1 nm.

1-3. UV-visible light Spectrophotometric  analysis

UV-visible spectrophotometric analysis was performed using UV1650PC (Shimadzu, Japan). The silver nanoparticles formed in the DMF solution can be detected by UV spectra of the separated bands.

As shown in Figure 4, pure DMF did not show any absorption band. However, the DMF solution containing silver nanoparticles showed a clear absorption band indicating silver nanoparticles at 422 nm.

< Experimental Example  2> Characterization of gelatin-polyurethane nanofiber

2-1. Scanning Electron Microscope ( SEM ) observe

The morphology of the nanofibers was observed using a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) (Hitachi S-4700, Japan) at an accelerating voltage of 15 kV.

As a result, as shown in Figs. 5A (EN-1), 5b (EN-2) and 5c (EN-3), in the case of EN-1, EN-2 and EN- Is well formed. However, as shown in FIG. 5d (EN-4), when the content of the silver nanoparticles increases, small sized beads are formed and a dirty type strand is formed.

This phenomenon is due to excessive silver nanoparticles. Because silver changes the surface tension and viscosity of the electrospinning solvent. As a result, during the electrospinning process, spray ejection collapses to form beads.

2-2. Transmission electron microscope ( TEM ) observe

The nanofibers prepared in the examples were observed using a transmission electron microscope (TEM) (H-7100, Hitachi, Japan) at room temperature with an acceleration voltage of 100 kV.

As shown in FIGS. 6a (EN-1), 6b (EN-2) and 6c (EN-3), TEM micrographs confirmed silver nanoparticles present in the polyurethane strands of nanofibers. Since EN-1 uses pure DMF, there are no silver nanoparticles. In EN-2 and EN-3, nanosized silver nanoparticles are clearly present in the fiber strand. The amount of silver nanoparticles observed increases with the silver nanoparticles contained in the DMF solution. However, EN-4 had too many beads to obtain fiber strands, and TEM images could not be confirmed.

2-3. Energy dispersive  X-ray spectroscopy (EDS)

Energy dispersive X-ray spectroscopy (EDS) was used to analyze the constituent elements of polyurethane single fibers, gelatin single fibers and polyurethane single fibers containing silver nanoparticles.

As a result, as shown in Figs. 7A, 7B, and 7C, the polyurethane fiber control group had only two elements, C and O. Gelatin fibers have three elements, C, O and N, because they have amine groups. Silver nanoparticle-containing polyurethane fibers additionally contained silver. These results indicate that the bi-electrospun nanofibers are well fibrous and contain silver nanoparticles in the polyurethane strands.

2-4. infrared ray Spectrophotometric  analysis

The molecular structure of polyurethane nanofibers, gelatin nanofibers, and nanofibers (EN-1) of the present invention prepared by electrospinning was analyzed by Fourier transform infrared spectrometer (Spectrum ™ One System, Perkin- Elmer).

FT-IR spectra were measured at 500-4000 cm &lt;&quot; ^{1 &} gt ;. As a result, as shown in Fig. 8, the polyurethane nanofibers showed peaks at 2920 cm ^-1 (CH), 1230 cm ^-1 (CC), and 1110 cm ^-1 (CO). The gelatin nanofibers exhibited additional peaks at approximately 1640 cm ^-1 (amide I, C = O). EN-1 showed all the peaks of polyurethane nanofiber and gelatin nanofiber.

Thus, it can be seen that the gelatin-polyurethane nanofibers are well formed by the dual-electrical radiation system.

< Experimental Example  3> Determination of Hydrophilic Properties of Nanofibers

To confirm the hydrophilicity of the nanofibers, moisture absorption and contact angle of the polyurethane nanofibers and the nanofibers (EN-1) prepared in the above examples were measured.

3-1. Water absorption measurement

To measure the water uptake, the dry sample was first weighed and then immersed in a 10 mL vial containing distilled water. After soaking for 1 hour, the sample was taken out of the water. Residual water on the surface was removed with paper tissue and weighed again. The amount of water absorption (%) was calculated by the following formula.

Water Absorption (%) = [(moisture _{after -} water _before ) / water _before ] x100%

As a result, as shown in Fig. 9, the polyurethane fibers (PU EN) absorbed a very small amount of moisture of about 15% for 10 to 120 seconds. On the other hand, EN-1 absorbed about 260% of its own mass of water for 120 seconds, showing excellent water uptake.

In addition, water absorption was observed by immersing the nanofibers in the cell culture medium.

As a result, as shown in Fig. 10, in the case of polyurethane fibers, the fibers floated on top of the medium during wetting (Fig. 10a), but EN-1 sank down the medium immediately after soaking (Fig.

3-2. moisture Contact angle  Measure

The contact angle of water was measured using a sessile drop method and a video camera (150, 82 SEO, Korea).

As a result, as shown in Fig. 11, the contact angle did not change until the polyurethane fiber reached 60 seconds. However, as the time changes from 0 second, 10 seconds, 30 seconds, and 60 seconds, EN-1 rapidly decreased to 97 °, 49 °, 29 °, and 0 °, respectively.

Thus, it can be seen that EN-1 contains gelatin having good hydrophilicity and therefore has much better wettability than polyurethane fibers.

< Experimental Example  4> Determination of release rate of silver nanoparticles and silver ions of the nanofiber of the present invention

4-1. Quantification of silver ions

Thermogravimetric analysis (TGA) was performed with TGA Q5000IR (TA Instruments, USA).

As a result, as shown in FIG. 12, all the samples exhibited similar curves in their overall shapes. However, weight difference occurred in the range of 500 ° C to 800 ° C. This phenomenon is due to the content of silver nanoparticles. All of the polymer compositions are removed at about 500 DEG C, so that only silver nanoparticles remain thereafter.

Thus, it can be seen that the silver nanoparticles are successfully embedded in the gelatin-polyurethane nanofibers. In the small diagram of FIG. 12, EN-4 contains about 3.8 wt.% Silver nanoparticles .

4-2. Measurement of release rate of silver ion

The emission profile of silver ions was evaluated by an inductively coupled plasma mass spectrometer (ICP-MS) (Agilent 7500cx, USA).

As shown in FIG. 13, when the content of silver contained in the nanofibers is increased, the amount of silver ions released increases for 2 hours.

< Experimental Example  5> Measurement of Antibacterial Activity of Gelatin-Polyurethane Nanofibers Containing Nanoparticles in vitro  Antibacterial test)

Porphyromonas gingivalis ( P. gingivalis ), prevotella intermedia ( P. intermedia ) and aggregatibacter actinomycetemcomitans ( A. actinomycetemcomitans ) Three bacterial pathogens were tested in vitro . These bacteria are oral pathogens that are known to cause periodontal disease.

5-1. Culture of bacteria

For the antimicrobial test, P. gingivalis W83 and P. intermedia ATCC49046 were mixed with 5 μg / ml of hemicellulose (1 μg / ml), vitamin K ₁ (5 μg / ml) (85% N ₂ , 10% H ₂ , and 5% CO ₂ ) (Forma Scientific Company, Marietta, OH, USA) for two days at 37 ° C. To grow in the liquid medium, the cells of the bacteria grown in the brucella blood agar were incubated with 10 mL of brucella broth containing 5 μg / ml of hemicellulose and 1 μg / ml of vitamin K ₁ . It was then incubated aerobically at &lt; RTI ID = 0.0 &gt; 37 C. &lt; / RTI &gt;

A. actinomycetemcomitans Y4 was initially grown in BHI agar at 37 ° C for 1 day in a CO ₂ incubator. The bacterial cells grown in agar medium were then incubated in 10 mL BHI broth in a CO ₂ environment at 37 ° C.

Each bacterial strain was grown in an initial exponential growth phase (600 nm measuring optical density 0.3-0.4) in liquid medium. Bacterial cells were harvested by centrifugation at 12000 g for 10 min and then re-suspended in sterile phosphate buffered saline (PBS, pH 7.4) to give a final concentration of 5 x 10 ⁷ CFU / mL.

5-2. in vitro  Antimicrobial activity measurement

100 [mu] l of each of the diluted bacterial suspensions was dropped onto the surface of the nanofibers EN-1 to EN-4 prepared in the examples. Aliquots (30 μl) were removed from the suspension at defined time intervals and viable cells were quantified by ATP-bioluminescence using the BacTier-Glo ™ Microbial Cell Viability Assay Kit (Promega, Madison, Wis.) As directed by the manufacturer.

As a result, as shown in Figs. 14 to 16, during the incubation time of 120 minutes, EN-1 showed no significant antimicrobial activity and showed a slight decrease in bacterial growth. EN-2, EN-3 and EN-4 inhibited the growth of bacterial cells at all stages. Therefore, it can be seen that the silver nanoparticles contained in the nanofiber can be used as a dressing material having excellent antibacterial activity.

In addition, the amount of silver nanoparticles contained increased the inhibition rate. That is, the amount of silver nanoparticles plays an important role in the eradication of bacteria.

Claims (8)

Gelatin-polyurethane nanofibers containing silver nanoparticles. The nanofibers according to claim 1, wherein the nanofibers are antimicrobial. The nanofiber of claim 1, wherein the silver nanoparticles are present only in polyurethane fibers. A wound dressing material comprising the nanofiber of claim 1. 5. The dressing material of claim 4, wherein the wound dressing material is an oral wound dressing material. 1) dissolving silver nitrate in a solvent of N, N-dimethylformamide (DMF);
2) mixing the solution prepared in step 1) with a solution containing polyurethane; And
3) filling the solution prepared in step 2) and the solution containing gelatin into different syringes and electrospinning simultaneously
The method of producing a nanofiber according to claim 1, The process according to claim 6, wherein the solution containing polyurethane in step 2) is a polyurethane dissolved in DMF / tetrahydrofuran (THF) solvent. The process according to claim 6, wherein the gelatin-containing solution of step 3) is gelatin dissolved in a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solvent.

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