An antibacterial material, nanofiber material and preparation and application thereof

Abstract

The application relates to the technical field of biomedical materials, and provides an antibacterial material, a nanofiber material and preparation and application thereof, wherein the antibacterial material is obtained by reducing silver nitrate with an elaeagnus angustifolia extract; the nanofiber material is obtained by electrospinning after the elaeagnus angustifolia extract, silver nitrate and a polymer are dissolved in a mixed solvent to obtain a spinning solution; the mixed solvent is dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, which is used for reducing silver nitrate with the elaeagnus angustifolia extract while forming the spinning solution; and the polymer is a polymer soluble in N,N-dimethylformamide. The nanofiber material prepared by the application has good hydrophilicity, water absorption, oxidation resistance and bacteriostasis, can be used for wound dressings, and the preparation method is simple, easy to implement, low in cost and environment-friendly and pollution-free.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to an antibacterial material, a nanofiber material, and their preparation and application. Background Technology

[0002] Wound healing is a complex process consisting of four consecutive physiological stages involving hemostasis, inflammatory response, cell proliferation, and tissue remodeling. During this period, bacteria can easily infect the wound, leading to increased inflammation and hindering healing. An ideal wound dressing should have multiple functions, not only removing excess free radicals at the wound site but also providing a moist healing environment. Currently, most commercially available dressings are gauze, which, due to its relatively large pores, cannot prevent the entry of external bacteria or inhibit bacteria already present in the wound during the healing process.

[0003] Currently, nanofiber membranes prepared by electrospinning possess high specific surface area and porous structure, similar to the structure of the extracellular matrix, providing an ideal microenvironment for cell adhesion, proliferation, and further differentiation. Due to their high porosity, nanofiber membranes prepared by electrospinning can promote gas-liquid exchange in tissue cells, preventing excessive dehydration and drying of wounds. To inhibit the proliferation of bacteria already present in wounds, antibacterial substances are generally added to inhibit bacterial growth and accelerate wound healing. Commonly used antibacterial substances include natural antibacterial components, organic antibacterial agents, and inorganic antibacterial agents. Among them, nanosilver is an important antibacterial agent. Due to its antibacterial, reducing, oxidizing, and catalytic properties, nanosilver is widely used in biosensing, food industry, medical devices, plastics, and textiles. However, the current preparation of nanosilver using chemical reduction methods requires the use of chemical reagents such as hydrazine hydrate and sodium borohydride, which have negative environmental impacts. Furthermore, these chemical reagents remain on the surface of nanosilver and are difficult to remove, significantly limiting its application in medicine and biocatalysis.

[0004] Therefore, this invention is proposed. Summary of the Invention

[0005] This invention provides an antibacterial material, a nanofiber material, and their preparation and application, in order to address the shortcomings of existing antibacterial materials in the biomedical field. By designing a new antibacterial material and preparing nanofiber materials containing the antibacterial material using a specific mixed solvent, the resulting nanofiber materials exhibit good hydrophilicity, water absorption, antioxidant properties, and antibacterial activity. Furthermore, the preparation method is simple, cost-effective, and environmentally friendly.

[0006] Specifically, the present invention provides an antibacterial material comprising: silver nitrate obtained by reducing jujube extract.

[0007] Elaeagnus angustifolia L. is a deciduous shrub or small tree of Elaeagnaceae Elaeagnus, mainly distributed in Xinjiang and Ningxia of China. Elaeagnus angustifolia L. mainly contains saccharides, and also contains proteins, tannins, flavones and other components, and has the functions of inhibiting bacteria, anti-inflammation and analgesia. Based on in-depth research on biomedical materials, it is found that the extract of Elaeagnus angustifolia L. has certain medicinal value, and when the extract is mixed with silver nitrate, the two can generate a reduction reaction to generate nano-silver, so that the antioxidant and antibacterial effects of the product are significantly improved. The extract of Elaeagnus angustifolia L. used in the application can well avoid the problems caused by the chemical reduction method for preparing nano-silver. In addition, when the product is used in biomedical materials, the antioxidant and antibacterial effects of the biomedical materials can be significantly improved, and other components in the product can also adjust other application properties of the biomedical materials.

[0008] The application further provides a preparation method of the antibacterial material.

[0009] In the experiment, it is found that when dimethyl sulfoxide is used as the solvent, the reduction of silver nitrate by the extract of Elaeagnus angustifolia L. is more favorable, and nano-silver with more uniform particle size is obtained.

[0010] According to the preparation method of the antibacterial material, the extract of Elaeagnus angustifolia L. is obtained by extracting Elaeagnus angustifolia L. powder with ethanol.

[0011] The extract of Elaeagnus angustifolia L. prepared by the above method has higher effective components and better reduction effect on silver nitrate. More specifically, the method for preparing the extract of Elaeagnus angustifolia L. in the application is as follows: Elaeagnus angustifolia L. powder is blended with ethanol, and then water bathed and statically placed for 12-16 hours; the supernatant is filtered and then rotary evaporated to obtain 20-30 mL of viscous liquid; and then the viscous liquid is freeze-dried at-80 DEG C to obtain the extract of Elaeagnus angustifolia L. (solid).

[0012] The Elaeagnus angustifolia L. powder is obtained by crushing and passing through a 40-mesh screen.

[0013] The volume fraction of ethanol is 70-80%, and the water bath temperature is 70-80 DEG C.

[0014] According to the preparation method of the antibacterial material, the mass ratio of the extract of Elaeagnus angustifolia L. to the silver nitrate is (1-15):(3-4).

[0015] Preferably, the reduction reaction is carried out at a temperature of 20-40 DEG C for more than 6 hours.

[0016] It is found through a large number of experiments that the elaeagnus angustifolia extract has excellent reducing property, and the elaeagnus angustifolia extract can reduce silver nitrate when the mass ratio of the elaeagnus angustifolia extract to the silver nitrate is only 1:3.4, and with the increase of the mass ratio of the elaeagnus angustifolia extract to the silver nitrate to 15:3.4, the reducing degree gradually increases, and the comprehensive performance of the obtained antibacterial material is better, such as the improvement degree of hydrophilicity, the free radical scavenging efficiency and the like, and when the amount of the elaeagnus angustifolia extract is further increased, the performance does not continuously improve, and the preparation difficulty is increased.

[0017] The application further provides a preparation method of the nanofiber material, comprising the following steps: dissolving the elaeagnus angustifolia extract, the silver nitrate and the polymer in a mixed solvent to obtain a spinning solution, and then performing electrostatic spinning to obtain the nanofiber material.

[0018] The mixed solvent is dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, which is used to form the spinning solution and reduce the silver nitrate in the elaeagnus angustifolia extract.

[0019] The polymer is a polymer that can be dissolved in N,N-dimethylformamide.

[0020] When the nanofiber material is prepared by using the electrostatic spinning process, the selection of the solvent in the spinning solution is very important, and in the application, it is accidentally found that the mixed solvent composed of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran can dissolve the elaeagnus angustifolia extract, the silver nitrate and the polymer, so that a stable and uniform spinning solution is obtained, and the comprehensive performance of the nanofiber obtained from the spinning solution is excellent, and compared with the nanofiber obtained by adding the elaeagnus angustifolia extract or the silver nitrate alone, the nanofiber obtained by using the application has significantly improved antioxidant and antibacterial effects, and more importantly, if the composition of the mixed solvent is changed, the nanofiber material of the application cannot be prepared.

[0021] More specifically, the electrostatic spinning process used in the application is as follows: the spinning solution is loaded into a 10 mL syringe with a flat needle, and the electrostatic spinning is performed under the conditions that the voltage is 18-22 kV, the distance from the needle tip to the roller is 18-20 cm, the spinning speed is 0.8-2 mL / h, the inner diameter of the needle is 0.7-0.9 mm, the temperature is 25-30 DEG C, and the relative humidity is less than 30%, and the spinning is performed for 8-16 h, and then the nanofiber film containing silver nanoparticles is obtained by placing the nanofiber film in a 60 DEG C vacuum drying machine for 48 h.

[0022] According to the preparation method of the nanofiber material provided in the application, in order to more efficiently obtain a stable and uniform spinning solution, the preparation of the spinning solution includes the following steps: first, the elaeagnus angustifolia extract and the silver nitrate are dissolved in the mixed solvent to obtain a mixed solution, and then the polymer is dissolved in the mixed solution to obtain the spinning solution.

[0023] The mass ratio of the elaeagnus angustifolia extract to the silver nitrate is (1-15):(3-4).

[0024] Further preferably, the mixed solvent is composed of 1 part of dimethyl sulfoxide, 2-4 parts of N,N-dimethylformamide and 6-8 parts of tetrahydrofuran, in terms of volume fraction.

[0025] It is also found in the experiment that the ratio of the components in the mixed solvent has a significant influence on the performance of the nanofiber material, and if the ratio is not properly selected, the surface of the obtained nanofiber material may be bonded, and even it is difficult to be spun into a shape.

[0026] According to the nanofiber material provided by the application, the polymer is polyurethane or polyvinylidene fluoride, and preferably polyurethane (molecular weight is about 130000);

[0027] Preferably, the mass concentration of the polymer in the spinning solution is 10-30%.

[0028] The type of polymer has a significant influence on the application of the nanofiber material obtained in the application, and in practice, the nanofiber material is mainly used in the biological field, which often requires the nanofiber material to have high hydrophilicity. It is found in the experiment that when a hydrophobic polymer is used, the obtained nanofiber material has significantly improved oxidation resistance and antibacterial effect, and its hydrophilicity is also significantly improved, with high water absorption rate, which is very beneficial to the use of the nanofiber material as a medical material such as wound dressing.

[0029] According to the nanofiber material provided by the application, the mass-volume ratio of the Elaeagnus angustifolia extract and the mixed solvent in the spinning solution is (0.01-0.15) g:10 mL, or the mass ratio of silver nitrate and polymer in the spinning solution is 1-4:100.

[0030] As the core component in the spinning solution, the content of the Elaeagnus angustifolia extract, silver nitrate and polymer plays a key role. Generally speaking, the higher the proportion of the Elaeagnus angustifolia extract and silver nitrate, the more significant the influence on the hydrophilicity, oxidation resistance and antibacterial effect of the obtained nanofiber material. Considering the ease of spinning and the physical and mechanical properties of the obtained nanofiber material, the comprehensive performance of the obtained nanofiber material is best when the spinning solution is configured according to the above-mentioned ratio.

[0031] The application also provides a nanofiber material prepared by the preparation method of the nanofiber material as described above.

[0032] The application also provides a wound dressing comprising the nanofiber material as described above; preferably, the water vapor transmission rate of the nanofiber material is 2400 g.m -2 .d -1 Above, the DPPH free radical scavenging rate is 18% or more, the antibacterial rate diameter of Staphylococcus aureus is 2 cm or more, and the antibacterial rate diameter of Escherichia coli is 1.8 cm or more.

[0033] The application provides an antibacterial material, a nanofiber material and preparation and application thereof. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0035] Fig. 1 is the XRD test result graph of the antibacterial material prepared in Example 1 provided by the application;

[0036] Fig. 2 is the ultraviolet test result graph of the antibacterial material prepared in Example 1 provided by the application;

[0037] Fig. 3 is the XPS test result graph of the nanofiber film prepared in Example 2 provided by the application. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely in combination with the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application.

[0039] The specific technology or condition not mentioned in the embodiments is carried out according to the technology or condition described in the literature in the art or according to the product instruction. The reagent or instrument not mentioned by the manufacturer is a conventional product that can be purchased through a regular channel.

[0040] The application will be described below in combination with Figs. 1-3 to describe an antibacterial material, a nanofiber material and preparation and application thereof.

[0041] The test method of the present application is as follows:

[0042] (1) Water contact angle test: The nanofiber membrane was cut into 10*20mm size, and fixed on a glass slide with adhesive tape to ensure that the sample was flat and had no shadows. The initial water contact angle of the nanofiber membrane was tested using a water contact angle tester. Each sample was tested 3 times and the average value was taken.

[0043] (2) Water vapor permeability test: A certain temperature of distilled water was placed in a moisture permeable cup, and the sample was placed with the test surface facing up to seal the cup opening. After weighing, it was placed in a constant temperature water type electric heating incubator (temperature 37±1℃, relative humidity 23.7±1%, air flow speed 0.3-0.5m / s). After 24h, the amount of water passing through the membrane was determined by the weight change of the moisture permeable cup. The calculation formula of the daily water vapor permeability of the nanofiber membrane is as follows:

[0044]

[0045] In the formula, W1 is the weight (g) of the moisture permeable cup covering the nanofiber membrane before being placed in the constant temperature water type electric heating incubator, W2 is the weight (g) of the moisture permeable cup covering the nanofiber membrane after being placed in the constant temperature water type electric heating incubator for 24h, and S is the area of the moisture permeable cup opening. Each sample was set up 3 parallel experimental groups.

[0046] (3) Antioxidant performance test: 20mg of nanofiber membrane was dissolved in anhydrous ethanol to prepare a 0.011mg / mL DPPH alcohol solution. The nanofiber membrane extract and 2mL DPPH alcohol solution were mixed, and the absorbance of the solution was measured at 512nm using a UV spectrophotometer after 30min of light shielding. Each sample was tested 3 times and the average value was taken, and the free radical scavenging rate K(%) formula is as follows:

[0047]

[0048] In the formula, A0 is the absorbance at 512nm of the control group, A1 is the absorbance at 512nm of the sample, and A2 is the absorbance at 512nm of ethanol.

[0049] (4) Antimicrobial performance test: The nanofiber membrane with a diameter of 12mm was sterilized under ultraviolet light for 1h for standby. Escherichia coli or Staphylococcus aureus was coated on agar medium (LB), and the nanofiber membrane was placed on the medium, and the diameter of the inhibition zone was measured after 18h of incubation at 37℃.

[0050] The preparation process of the Elaeagnus angustifolia extract used in the application is as follows: Elaeagnus angustifolia powder is blended with ethanol with a volume fraction of 75%, and is placed in a water bath at a temperature of 75℃ for 14h. The supernatant is filtered and rotary evaporated to obtain 25mL of viscous liquid, which is then freeze-dried at-80℃ to obtain the Elaeagnus angustifolia extract. The Elaeagnus angustifolia powder is obtained by grinding and passing through a 40 mesh screen.

[0051] Room temperature in the present application refers to 25±2℃.

[0052] Antibacterial material

[0053] A preparation method of an antibacterial material is as follows: 0.05g of a saussurea involucrata extract and 0.034g of silver nitrate are dissolved in dimethyl sulfoxide to perform a reduction reaction at room temperature, and the mixture is stirred overnight to obtain the antibacterial material.

[0054] The obtained antibacterial material is subjected to XRD (the test sample is the mixture after the above reaction dried at room temperature to remove the solvent) and ultraviolet testing, and the test results are shown in Figs. 1-2 From the figures, it can be seen that various diffraction peaks

[111] ,

[200] ,

[220] ,

[311] of different intensities exist on the XRD spectrum, which correspond to the diffraction peaks of the metal silver crystal state, which confirms that the natural dispersed silver nanoparticles are synthesized. Fig. 1 From the figures, it can be seen that a relatively strong absorption peak appears at 420nm, indicating that the silver nanoparticles appear in the solution. Fig. 2

[0055] Nanofiber membrane

[0056] A preparation method of a nanofiber membrane is as follows:

[0057] (1) 0.05g of a saussurea involucrata extract is added into 10mL of a mixed solution composed of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, and after stirring and dissolving, 0.034g of silver nitrate is added to obtain a mixture, wherein the volume ratio of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran is 1:3:7.

[0058] (2) Preparation of the spinning solution: polyurethane is added into the mixture obtained in step (1), and a magnetic stirrer at 600rmp is used to stir overnight at room temperature to obtain the spinning solution, wherein the mass fraction of polyurethane in the obtained spinning solution is 20%.

[0059] (3) Electrospinning: the spinning solution obtained in step (1) is injected into an electrospinning injector, and the spinning conditions are set as follows: voltage 20kV, distance from the needle tip to the drum 19cm, spinning speed 1mL / h, inner diameter of the needle 0.8mm, temperature 26℃, relative humidity 20%, electrospinning is performed, the product is placed in a vacuum drying machine at 60℃ for 48h to obtain the nanofiber membrane.

[0060] The nanofiber membrane is subjected to XPS testing, and the test results are shown in Fig. 3 From the figures, it can be seen that two obvious energy bands at 373.08eV and 367.08eV are attributed to Ag 3d​3 / 2 and Ag 3d 5 / 2 The binding energy of Ag 3d and Ag 3d is 6eV, which indicates that the synthesized AgNPs are zero-valent, and it is proved that the nanofiber membrane contains Ag nanoparticles.

[0061] Example 3 nanofiber membrane

[0062] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that the mass ratio of polyurethane to silver nitrate is 100:2, and the mass ratio of the extract of Elaeagnus angustifolia L. to silver nitrate remains unchanged.

[0063] Example 4 nanofiber membrane

[0064] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that the mass ratio of polyurethane to silver nitrate is 100:3, and the mass ratio of the extract of Elaeagnus angustifolia L. to silver nitrate remains unchanged.

[0065] Example 5 nanofiber membrane

[0066] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that the amount of other substances remains unchanged, and the mass of the extract of Elaeagnus angustifolia L. is reduced to 0.01g.

[0067] Example 6 nanofiber membrane

[0068] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that the amount of other substances remains unchanged, and the mass of the extract of Elaeagnus angustifolia L. is increased to 0.15g.

[0069] Example 7 nanofiber membrane

[0070] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that the mass of polyurethane is replaced by polyvinylidene fluoride.

[0071] Comparative Example 1

[0072] A method for preparing a nanofiber membrane, the specific steps of which are as follows:

[0073] (1) Add polyurethane to a mixed solution composed of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, and stir overnight at room temperature using a magnetic stirrer at 600rmp to obtain a spinning solution, wherein the mass fraction of polyurethane in the obtained spinning solution is 20%, and the volume ratio of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran is 1:3:7.

[0074] Comparative Example 2

[0075] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that step (1) is specifically as follows:

[0076] 0.034 g of silver nitrate was added to 10 mL of a mixed solution composed of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, and stirred and dissolved to obtain a mixed solution, wherein the volume ratio of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran was 1:3:7.

[0077] Comparative Example 3

[0078] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that step (1) is specifically as follows:

[0079] (1) 0.05 g of a haloxylon extract was added to 10 mL of a mixed solution composed of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran, and stirred and dissolved to obtain a mixed solution, wherein the volume ratio of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran was 1:3:7.

[0080] Comparative Example 4

[0081] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that N,N-dimethylformamide is replaced with an equal volume of dimethyl sulfoxide, and it was found in the test that polyurethane could not be dissolved in the mixed solution, clogging the spinning needle, and spinning could not be performed.

[0082] Comparative Example 5

[0083] A method for preparing a nanofiber membrane, the specific steps of which are basically the same as those of Example 2, except that tetrahydrofuran is replaced with an equal volume of dimethyl sulfoxide, and it was found in the test that a nanofiber membrane with certain porosity could not be formed.

[0084] The water contact angle, water vapor permeability, antioxidant properties and antibacterial properties of the nanofiber membranes prepared in Examples 2 to 7 and Comparative Examples 1 to 3 were tested, and the test results are as follows:

[0085]

[0086] It can be seen from the comparative example 2 that silver nitrate can make the nanofiber membrane have certain antibacterial function, and it can be seen from the comparative example 3 that the Elaeagnus angustifolia extract cannot make the prepared nanofiber membrane have antibacterial function, but it can be seen from the example 2, the example 5 and the example 6 that when the Elaeagnus angustifolia extract and the silver nitrate are mixed, the antibacterial function of the nanofiber membrane can be improved by more than 1 times, and with the increase of the Elaeagnus angustifolia extract, the antibacterial function and the antioxidant property of the nanofiber membrane can be continuously improved. In addition, it can be seen from the example 7 and the comparative example 1 that the Elaeagnus angustifolia extract and the silver nitrate added into the polyurethane can also make the hydrophobic polyurethane nanofiber membrane change into the hydrophilic nanofiber membrane, which is particularly suitable for wound dressings and the like.

[0087] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing a nanofiber material, characterized by, Comprising: After dissolving the Elaeagnus angustifolia extract, silver nitrate and polymer in a mixed solvent to obtain a spinning solution, electrospinning is performed, and the nanofiber material is obtained. The mixed solvent consists of 1 part of dimethyl sulfoxide, 2-4 parts of N,N-dimethylformamide and 6-8 parts of tetrahydrofuran by volume fraction, and is used to form the spinning solution and reduce the silver nitrate in the Elaeagnus angustifolia extract at the same time; The polymer is a polymer soluble in N,N-dimethylformamide, and the polymer is polyurethane or polyvinylidene fluoride; The mass ratio of the Elaeagnus angustifolia extract to the silver nitrate is (1-15):(3-4); The mass concentration of the polymer in the spinning solution is 10-30%; The mass-volume ratio of the Elaeagnus angustifolia extract to the mixed solvent in the spinning solution is (0.01-0.15) g:10 mL, or the mass ratio of the silver nitrate to the polymer in the spinning solution is 1-4:

100.

2. The method of claim 1, wherein the nanofiber material is prepared by electrospinning. The preparation of the spinning solution comprises: first dissolving the Elaeagnus angustifolia extract and the silver nitrate in a mixed solvent to obtain a mixed solution, and then dissolving the polymer in the mixed solution, and the nanofiber material is obtained.

3. The method of claim 1 or 2, wherein the nanofiber material is prepared by electrospinning. The polymer is polyurethane.

4. The nanofiber material prepared by the method of any one of claims 1-3.

5. A wound dressing comprising the nanofiber material of claim 4.

6. The wound dressing of claim 5, wherein, The water vapor permeability of the nanofiber material is 2400 g.m -2 .d -1 The DPPH radical scavenging rate is 18% or more, the antibacterial rate diameter against Staphylococcus aureus is 2 cm or more, and the antibacterial rate diameter against Escherichia coli is 1.8 cm or more.

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