CN101187089A - Antibacterial nanofibers blended with silk fibroin and polyvinyl alcohol and preparation method thereof - Google Patents

Abstract

The invention discloses a nanofiber and a preparation method thereof. Its components are silk fibroin, Ag elemental particles and polyvinyl alcohol; Silk fibroin; b. Dissolving silk fibroin in acid solution to obtain regenerated silk fibroin acid solution; c. Polyvinyl alcohol is dissolved to obtain polyvinyl alcohol solution; d. The two solutions are blended; e. Add silver system Inorganic salt; f. Electrospinning with a silver electrode to obtain a blended nanofiber mat; g. Heat-treating the blended nanofiber mat at a temperature of 100-150°C for 2-5 minutes, and then irradiating it with ultraviolet light After 3-5 hours of treatment, silk fibroin and polyvinyl alcohol blended antibacterial nanofibers are obtained. The mechanical property of the fiber is superior to that of pure silk fibre, good biocompatibility and antibacterial performance, and is suitable for biomedical materials, especially tissue engineering scaffold materials.

Description

Antibacterial nanofibers blended with silk fibroin and polyvinyl alcohol and preparation method thereof

technical field

The invention relates to a nanofiber and a preparation method thereof, in particular to a nanoscale antibacterial fiber blended with regenerated silk fibroin and polyvinyl alcohol and a preparation method thereof, belonging to the technical field of nanoscale fiber preparation, and the prepared material can be widely used in the fields of biology and medicine.

Background technique

Silk is rich in sources in my country. It is mainly composed of silk fibroin and sericin. Silk fibroin is non-toxic, non-irritating, and non-allergic. It has good biocompatibility and can be prepared into films, gels, microcapsules, etc. Due to its unique physical and chemical properties, silk fibroin materials are widely studied in the field of biomedical materials, such as immobilized enzyme materials, cell culture substrates, drug sustained release agents, artificial organs, etc. Due to structural changes during processing, regenerated silk fibroin materials are difficult to meet the requirements as biomedical materials. In order to make up for the lack of silk fibroin in mechanical properties and thermal stability, silk fibroin is mainly blended with other materials with better mechanical properties through chemical modification. For example: cellulose, polyurethane, polyethylene oxide (PEO), chitin, gelatin, chitosan, polyvinyl alcohol, etc.

As a synthetic material, polyvinyl alcohol has the characteristics of non-toxic, water-soluble, biocompatible and biodegradable, and is also widely used in biochemical and biomedical materials. At the same time, polyvinyl alcohol has good mechanical properties and good hydrophilicity. advantage.

The nanofibrous scaffold has high porosity, that is, a highly porous structure, which can provide more structural space for cell generation to promote the exchange of nutrients and metabolites between the scaffold and the environment, while the electrospun fiber composition The micropores in the nonwoven fabric are continuous, and the resistance caused by nano-scale fibers to cell migration is extremely small, which is very conducive to cell proliferation.

Chinese invention patent CN1244727C discloses a method for manufacturing regenerated silk protein ultrafine fibers. Water is used as a solvent, and the regenerated silk fibroin is dissolved and directly electrospun to obtain the required regenerated silk protein ultrafine fibers. However, the fibers produced by this method The shape is relatively flat, the thickness is different, it is not smooth, and the flexibility of the fiber mat is not good, which reduces its practical value. Chinese invention patent application CN1818163A discloses a silk fibroin and polyvinyl alcohol blended nanofiber and its preparation method, using pure silk as the main raw material, after degumming, dissolving and other processes, adding polyvinyl alcohol to blend to prepare the blended nanofiber . The mat obtained by this method has a high dissolution rate in contact with water, and does not have antibacterial properties, which limits its application in biomedical materials.

So far, silk fibroin and polyvinyl alcohol blended nanofibers with antibacterial properties have not been reported.

Contents of the invention

In order to overcome the deficiencies in the prior art, the invention provides a silk fibroin-polyvinyl alcohol blended nanofiber that not only has good tissue compatibility with the human body, but also has good antibacterial effect and a preparation method thereof.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is: a kind of silk fibroin and polyvinyl alcohol blend antibacterial nanofiber, its component is silk fibroin, Ag elemental particles and polyvinyl alcohol; fiber diameter is 50 to 500 nanometers, the breaking strength is 0.3 to 0.5 cN/dtex, wherein the weight ratio of the silk fibroin to polyvinyl alcohol is 10 to 90:90 to 10, and the mass of the Ag elemental particles is 1% of the total mass. ~10%.

The present invention also provides a method for preparing silk fibroin and polyvinyl alcohol blended antibacterial nanofibers, the preparation steps of which are as follows:

a. Degumming silk into silk fibroin, and then obtaining pure regenerated silk fibroin material after dissolving, dialysis, purification and drying;

b. Dissolving the above-mentioned regenerated silk fibroin in formic acid or trifluoroacetic acid to prepare a regenerated silk fibroin acid solution with a mass fraction of 7-17%;

c. dissolving polyvinyl alcohol with a degree of polymerization of 1700 to 3000 in deionized water to obtain an aqueous solution of polyvinyl alcohol with a mass fraction of 4 to 12%;

d. Blending the obtained regenerated silk fibroin acid solution and polyvinyl alcohol aqueous solution, the weight ratio of silk fibroin and polyvinyl alcohol is 10～90:90～10;

e. adding silver-based inorganic salts containing 1 to 10% Ag ⁺ equivalent to the total mass of the solute in the above solution to obtain a spinning solution;

f. Using a high-voltage electrospinning method, the above-mentioned spinning solution is spray-spun to obtain a blended nanofiber felt, wherein the electrodes used are silver materials with a diameter of less than 1mm;

g. heat-treating the blended nanofiber mat at a temperature of 100-150° C. for 2-5 minutes, and then irradiating with ultraviolet light for 3-5 hours to obtain silk fibroin and polyvinyl alcohol blended antibacterial nanofibers.

In the above technical scheme, the silver-based inorganic salt described in step e is silver nitrate.

The principle of the present invention is as follows: In order to overcome the defect of poor flexibility of pure silk fibroin nanofibers, the present invention adopts the technical scheme of adding polyvinyl alcohol with good strength and toughness into the spinning solution. Due to the weak volatilization ability of water, the present invention uses organic acid as solvent, avoiding the defects that the fibers caused by water as solvent are relatively flat, have different thicknesses and are not smooth. Silver ions were added during the blending process of silk fibroin and polyvinyl alcohol to increase the antibacterial properties of the blended fiber mat. Silver has an adsorption effect on microorganisms in the liquid. After the microorganisms are adsorbed by silver, the enzymes that play a role in respiration will lose their effectiveness, and the microorganisms will die quickly. The bactericidal ability of silver ions is particularly strong. As long as each liter of water contains 2 parts per million of silver ions, most bacteria in the water can be killed.

In the invention, silver nitrate is added into the mixed solution, and a large amount of silver ions are precipitated into silver simple particles through heat treatment and ultraviolet irradiation after electrospinning. However, due to the poor activity of simple silver, if conventional metal materials are used as the electrode, the silver ions in the solution will be replaced and precipitated by the electrode, and the graphite electrode is easy to break when it is thinner due to its low strength. Therefore, The invention adopts the silver material with a diameter of less than 1mm as the electrode, which can meet the requirement of preparing the silver-containing nanofiber by adopting the electrospinning method.

Compared with the prior art, the present invention has the following obvious advantages:

1. Since the present invention uses natural silk and polyvinyl alcohol with better mechanical properties as the main raw materials, the blended fiber prepared not only maintains the good compatibility characteristics of natural silk protein and human body, but also improves its mechanical properties. At the same time, due to the addition of silver ions, the prepared blended fiber has a certain bactericidal effect, is more suitable for use in the field of biomedicine, and becomes an ideal fiber material for tissue engineering scaffolds.

2. In the electrospinning process of the present invention, the electrodes are made of silver material, which well makes up for the shortcomings of other conventional electrodes.

3. The blended nanofiber prepared by the present invention has excellent adsorption, air permeability, moisture permeability and filtration performance, and has a good application prospect.

Detailed ways

The present invention will be further described below in conjunction with embodiment:

Example 1:

Put 0.1 kg of leftover raw silk (the by-product of cocoon reeling in the silk reeling factory) into 5 liters of sodium carbonate aqueous solution with a concentration of 0.5%, boil for 0.5 hour, repeat the treatment six times, and try to remove the sericin and silk around the silk as much as possible. residual oil to obtain pure silk fibroin.

The pure silk fibroin after natural drying is swollen with a mixed solvent of calcium chloride:ethanol:water with a molar ratio of 1:2:8 for 1 to 2 days, and then stirred and dissolved in a water bath at 75°C for 2 hours. After 3 days of dialysis with deionized water, centrifugation to remove impurities, and then natural drying to obtain a regenerated silk fibroin membrane. The regenerated silk film was dissolved in formic acid with a mass fraction of 13% in a water bath at 70°C. Polyvinyl alcohol with a degree of polymerization of 2400 was dissolved in deionized water at a mass fraction of 7% in a water bath at 82°C. The above two solutions were fully mixed in a water bath at 70°C, the mass ratio of silk fibroin and polyvinyl alcohol was 1:1, and then Ag ⁺ silver nitrate with a mass fraction of 1‰ was added to prepare a spinning solution.

With internal diameter 0.5mm capillary nozzle tube as spinneret hole, spinneret electrode is silver material, and spinning solution amount 5ml in the capillary, under the nitrogen pressure effect, spinning speed is 2ml/h, capillary nozzle to the fiber collecting frame distance 12cm, The spinning voltage was 15KV.

At room temperature, the spinning solution is sprayed onto a screen receiving plate to obtain a regenerated silk fibroin and polyvinyl alcohol blended fiber mat with a fiber diameter of 50-300 nanometers.

The prepared blended nanofiber felt was heat-treated at 150° C. for 2 minutes, and then irradiated with ultraviolet light for 3 hours to obtain silk fibroin and polyvinyl alcohol blended nanometer antibacterial fibers. It can be used as the bottom surface material of medical covering binding materials, and has the advantages of non-toxic, non-irritating, antibacterial, good biocompatibility, and good contact.

Example 2:

First put 0.2 kg of leftover raw silk (by-product of cocoon reeling in silk reeling factory) into 10 liters of sodium carbonate aqueous solution with a concentration of 0.5%, boil for 0.5 hour, repeat the treatment six times, and try to remove the sericin and silk around the silk as much as possible. residual oil to obtain pure silk fibroin.

The pure silk fibroin after natural drying is swollen with a mixed solvent of calcium chloride:ethanol:water with a molar ratio of 1:2:8 for 1 to 2 days, and then stirred and dissolved in a water bath at 75°C for 3 hours. After 3 days of dialysis with deionized water, centrifugation to remove impurities, and then natural drying to obtain a regenerated silk fibroin membrane. The regenerated silk film was dissolved in trifluoroacetic acid with a mass fraction of 15% in a water bath at 70°C. Polyvinyl alcohol with a degree of polymerization of 1700 was dissolved in deionized water with a mass fraction of 8% in a water bath at 82°C. The above two solutions were fully mixed in a water bath at 70°C, the mass ratio of silk fibroin and polyvinyl alcohol was 1:2, and then Ag ⁺ silver nitrate with a mass fraction of 3‰ was added to prepare a spinning solution.

Use a capillary nozzle tube with an inner diameter of 0.5 mm as the spinneret hole, adopt a silver needle as an electrode, and have a spinning solution amount of 5 ml in the capillary tube, and the spinning rate under nitrogen pressure is 3 ml/h, and the distance from the capillary nozzle to the fiber collection rack is 12 cm. The voltage is 16KV.

At room temperature, the spinning solution is sprayed onto a screen receiving plate to obtain a regenerated silk fibroin and polyvinyl alcohol blended antibacterial fiber mat with a fiber diameter of 50-300 nanometers.

The prepared blended nanofiber mat was heat-treated at 120° C. for 3 minutes, and then irradiated with ultraviolet light for 5 hours to obtain silk fibroin and polyvinyl alcohol blended nanometer antibacterial fibers. It is used as the bottom surface material of medical covering and binding materials, which has the advantages of non-toxic, non-irritating, antibacterial, good biocompatibility, and good contact.

Claims (3)

1. fibroin albumen and polyvinyl alcohol blending antibacterial nanometer fiber, it is characterized in that: its component is fibroin albumen, Ag simple substance particle and polyvinyl alcohol; Fibre diameter is 50～500 nanometers, and fracture strength is 0.3～0.5cN/dtex, and wherein, the weight ratio of described fibroin albumen and polyvinyl alcohol is 10～90: 90～10, and the quality of described Ag simple substance particle is 1～10% of a gross mass.

2. the preparation method of fibroin albumen and polyvinyl alcohol blending antibacterial nanometer fiber is characterized in that preparation process is as follows:

A. silk is come unstuck into fibroin, after dissolving, dialysis, purification and dried, obtain pure regenerated silk material again;

B. above-mentioned regenerated silk is dissolved in formic acid or the trifluoroacetic acid, makes mass fraction and be 7～17% regenerated silk acid solution;

C. be that 1700～3000 polyvinyl alcohol is dissolved in the deionized water with the degree of polymerization, make mass fraction and be 4～12% polyvinyl alcohol water solution;

D. regenerated silk acid solution and the polyvinyl alcohol water solution with gained carries out blend, and the weight ratio of fibroin albumen and polyvinyl alcohol is 10～90: 90～10;

E. in above-mentioned solution, add and contain 1～10% the Ag that is equivalent to the solute gross mass ⁺Silver-based inorganic salt, make spinning solution;

F. adopt the high-voltage electrostatic spinning method, above-mentioned spinning solution is sprayed spin, make the blended nanofibre felt, wherein the electrode of Cai Yonging is silver material, and diameter is less than 1mm;

G. to the heat treatment 2～5 minutes under 100～150 ℃ temperature conditions of described blended nanofibre felt, handled 3～5 hours through UV-irradiation again, obtain fibroin albumen and polyvinyl alcohol blending antibacterial nanometer fiber.

3. the preparation method of fibroin albumen according to claim 2 and polyvinyl alcohol blending antibacterial nanometer fiber is characterized in that: the described silver-based inorganic salt of step e is silver nitrate.