CN113550021A

CN113550021A - Antibacterial nanofiber and preparation method thereof

Info

Publication number: CN113550021A
Application number: CN202110912325.7A
Authority: CN
Inventors: 徐岚; 尹静
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2021-08-10
Filing date: 2021-08-10
Publication date: 2021-10-26
Also published as: WO2023015565A1

Abstract

The application relates to an antibacterial nanofiber and a preparation method thereof, and the preparation method comprises the following steps: providing a spinning device: the spinning device comprises a liquid storage tank, a high-voltage power supply electrically connected with the liquid storage tank and a receiving piece arranged on one side of the liquid storage tank, wherein the receiving piece is grounded to form an electrostatic field with the liquid storage tank; preparing a spinning solution: weighing polylactic acid, chitosan and aloin, and dissolving in a solvent to form a spinning solution; preparing nano fibers: the spinning solution is placed in a reservoir, the spinning solution forming a jet under the action of an electrostatic field, the jet being received on a receiver to form the nanofibres. Through the mode, the nanofiber prepared by the method has high water vapor transmission rate, so that the application prospect of protecting the wound and promoting the wound to heal is achieved.

Description

Antibacterial nanofiber and preparation method thereof

[ technical field ] A method for producing a semiconductor device

The application relates to an antibacterial nanofiber and a preparation method thereof, and belongs to the technical field of nano spinning.

[ background of the invention ]

The skin is the outermost organ covering the whole body of the human body, is directly contacted with the external environment, and has the functions of protecting, excreting, regulating the body temperature and the like. However, the structure and function of this organ can be affected by cuts, burns, surgical incisions or disease. Some wounds are difficult to heal in a spatially organized and timely manner, otherwise microorganisms can invade the wound and stay in the permanent inflammatory stage. In turn, the wound needs to be protected with a dressing. However, conventional wound dressings are generally low cost raw materials, do not provide a moist environment, and adhere to wounds, causing pain.

Accordingly, there is a need for improvements in the art that overcome the deficiencies in the prior art.

[ summary of the invention ]

The present application aims to provide an antibacterial nanofiber and a preparation method thereof, wherein the nanofiber prepared by the method has a high water vapor transmission rate, so that a wound is protected and the healing of the wound is promoted.

The purpose of the application is realized by the following technical scheme: a method for preparing antibacterial nano-fibers comprises the following steps:

providing a spinning device: the spinning device comprises a liquid storage tank, a high-voltage power supply and a receiving piece, wherein the high-voltage power supply is electrically connected with the liquid storage tank, the receiving piece is arranged on one side of the liquid storage tank, and the receiving piece is grounded to form an electrostatic field with the liquid storage tank;

preparing a spinning solution: weighing polylactic acid, chitosan and aloin, and dissolving in a solvent to form a spinning solution;

preparing nano fibers: placing the spinning solution in the reservoir, the spinning solution forming a jet under the action of an electrostatic field, the jet being received on the receiver to form nanofibers.

In one embodiment, the solvent comprises chloroform and N, N-dimethylformamide in a ratio ranging from 10:0 to 6: 4.

In one embodiment, the ratio of chloroform to N, N-dimethylformamide is in the range of 9: 1.

In one embodiment, the receiving member includes a receiving body rotating around a rotating shaft, and a driving body driving the receiving body to rotate.

In one embodiment, the receiving body is cylindrical, and the cylindrical receiving body has an outer surface which is a receiving surface.

In one embodiment, the reservoir has a recess, and the bottom surface of the recess has an arc-shaped cross section.

The application also relates to the antibacterial nanofiber prepared by the preparation method of the antibacterial nanofiber.

Compared with the prior art, the method has the following beneficial effects: the polylactic acid, the chitosan and the aloin are dissolved in the solvent to prepare the spinning solution, the prepared nano fibers have uniform diameters and larger specific surface area of gaps, and the air permeability of the fiber membrane is improved; in addition, the hydrophobic property of the prepared nanofiber can prevent secondary injury of a wound caused by adhesion of skin and the dressing; meanwhile, the hydrophilic chitosan and the aloin can enhance the permeability of water vapor to the nano fibers, so that the water vapor transmission rate of the nano fibers is increased, and the healing of the wound can be promoted while the wound is protected.

[ description of the drawings ]

Fig. 1 is a flow chart of a method of making the antimicrobial nanofibers of the present application.

FIG. 2 is a diagram of an apparatus for preparing the antibacterial nanofiber according to the present application.

FIG. 3 is a cross-sectional view of a 7 wt% PLA using different ratios of CF to DMF of the present application, wherein (a) CF to DMF is 9:1, (b) CF to DMF is 8:2, (c) CF DMF is 7: 3.

FIG. 4 is a fiber morphology and diameter distribution for PLA/CS and PLA/CS/Aloin of the present application, where the mass fraction of CS in (a) is 1 wt%, (b) is 1.5 wt%, (c) is 2 wt%, (d) is the fiber morphology and diameter distribution for the addition of Aloin when the mass fraction of CS is 1 wt%.

FIG. 5 is a graph of the effect of different solvent ratios on the morphology and diameter distribution of 7 wt% PLA fibers, where (a) CF: DMF is 10:0, (b) CF: DMF is 9:1, (c) CF: DMF is 8:2, (d) CF: DMF is 7:3, and (e) CF: DMF is 6: 4.

[ detailed description ] embodiments

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. It should be further noted that, for the convenience of description, only some of the structures related to the present application are shown in the drawings, not all of the structures. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "comprising" and "having," as well as any variations thereof, in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Referring to fig. 1 to 4, a method for preparing an antibacterial nanofiber according to a preferred embodiment of the present application includes:

s1: providing a spinning device: spinning equipment includes liquid storage tank 1, the high voltage power supply 3 of being connected with liquid storage tank 1 electricity and set up and receive piece 2 in 1 one side of liquid storage tank, receives piece 2 ground connection and in order to form the electrostatic field between 1 with the liquid storage tank. The liquid storage tank 1 has a concave portion 11, and the cross section of the bottom surface of the concave portion 11 is arc-shaped. The arc is the arc formed after the sphere is cut. And, the receiving member 2 includes a receiving body 21 rotated about a rotation shaft, and a driving body for driving the receiving body 21 to rotate, the driving body driving the receiving body 21 to rotate so that the jet flow is uniformly received on the receiving body 21. In order to ensure the homogeneity of the received jet, the receiving body 21 is cylindrical and the drive body is a motor in this embodiment. The cylindrical receiving body 21 has an outer surface, which is the receiving surface. In other embodiments, the shape of the receiving body 21 may be other, such as a rectangular parallelepiped, and is not limited herein, depending on the actual situation.

S2: preparing a spinning solution: polylactic acid, chitosan and aloin are weighed and dissolved in a solvent to form a spinning solution. In this example, the solvent comprises chloroform and N, N-dimethylformamide in a ratio ranging from 10:0 to 6: 4. Preferably, the ratio of chloroform to N, N-dimethylformamide is in the range of 9: 1.

S3: preparing nano fibers: the spinning solution is placed in a reservoir 1, which under the action of an electrostatic field forms a jet, which is received on a receiver 2 to form nanofibres, as shown in figure 2.

The application also relates to an antibacterial nanofiber prepared by the preparation method of the antibacterial nanofiber.

To specifically illustrate the enhancement of water vapor transmission rate and hydrophobicity of the nanofibers produced by the methods of the present application, several examples are given below.

Preparing different spinning solutions in advance, and spinning by using the different spinning solutions to prepare the nanofiber. The different spinning solutions were as follows:

respectively preparing pure polylactic acid (PLA), polylactic acid/chitosan (PLA/CS) and polylactic acid/chitosan/Aloin (PLA/CS/Aloin) solutions.

Preparation of pure polylactic acid (PLA) solution: 2.8g (7 wt%) of polylactic acid was put into 47.2g of a mixed solution of Chloroform (CF) and N, N-Dimethylformamide (DMF) (the ratio of the chloroform to the N, N-dimethylformamide solution was 10:0, 9:1, 8:2, 7:3 and 6:4, respectively), and stirred until the polylactic acid was completely dissolved, to obtain a polylactic acid solution.

Preparation of polylactic acid/chitosan (PLA/CS) solution: respectively adding 1 wt%, 1.5 wt% and 2 wt% of chitosan into 7 wt% of polylactic acid solution, wherein the solvent is chloroform and N, N-dimethylformamide solution with a ratio of 9:1, and stirring until the polylactic acid is completely dissolved to obtain polylactic acid (PLA)/Chitosan (CS) solution. Wherein, CF: the DMF was 9: 1.

Preparation of polylactic acid/chitosan/Aloin (PLA/CS/Aloin) solution: 2.8g of polylactic acid, 0.4g of chitosan and 6mg of aloin were put into a solution of 33.12g of chloroform and 3.68g of N, N-dimethylformamide, and stirred until the polylactic acid was completely dissolved, to obtain a polylactic acid (PLA)/Chitosan (CS)/aloin (aloin) solution. Wherein, CF: the DMF was 9: 1.

And then adding the prepared pure polylactic acid (PLA), polylactic acid/chitosan (PLA/CS) and polylactic acid/chitosan/Aloin (PLA/CS/Aloin) solutions into a liquid storage tank respectively for spinning to prepare pure polylactic acid nano fibers, polylactic acid/chitosan nano fibers and polylactic acid/chitosan/Aloin nano fibers. Wherein, the pure polylactic acid nano fiber and the polylactic acid/chitosan nano fiber have different shapes according to the different proportion of the spinning solution.

Example 1:

and testing the conductivity and viscosity of the prepared spinning solution. In nano-spinning, the diameter of the prepared nano-fiber is closely related to the conductivity and viscosity of the spinning solution. The higher the viscosity of the spinning solution, the larger the diameter of the prepared nanofiber; the lower the conductivity of the spinning solution, the larger the diameter of the produced nanofibers.

Specifically, the viscosity of the spinning solution was measured by a viscometer (SNB-1) and the conductivity of the spinning solution was measured by a conductivity meter (DDS-307A). The average value of each spinning solution was measured five times at the same room temperature, and the results are shown in table 1. It can be seen that the viscosity of the solution gradually decreases and the conductivity thereof gradually increases as the content of DMF increases. When chitosan is added to a 7 wt% polylactic acid solution, the viscosity of the solution increases and its conductivity decreases. After adding a small amount of aloin to the polylactic acid/chitosan solution, the viscosity and conductivity were similar to those before the addition. It can be seen that the addition of aloin has no effect on the conductivity and viscosity of the polylactic acid/chitosan solution.

TABLE 1 viscosity and conductivity of different components of the spinning solution

Example 2:

the surface structures and diameter distributions of the pure polylactic acid nanofibers, polylactic acid/chitosan nanofibers and polylactic acid/chitosan/aloin nanofibers prepared from different solutions were analyzed.

And (3) analyzing the surface structure: and (3) spraying gold on the surface of the nanofiber membrane to be detected, and observing the appearance of the nanofiber membrane by using a cold field emission Scanning Electron Microscope (SEM). Setting the accelerating voltage of the cold field to be 3kV or 5kV (adjusted according to the definition), and shooting and storing the electron microscope pictures with different magnification at room temperature. As shown in fig. 3, which is the spinning effect of PLA with a mass fraction of 7 wt% at different solvent ratios, it can be seen that the different ratios of solvents have a great influence on the morphology and uniformity of the fibers. With the increase of the content of DMF, the fiber surface is distributed from porous to non-porous. As shown in fig. 3 (a), when the ratio of CF and DMF is 9:1, that is, the PLA (90/10) fiber has uniform surface pore distribution and good fiber morphology, and both the surface and the inside of the nanofiber have pores; when the CF: when DMF is 8:2, pores are only formed inside the nano fibers; when the CF: when DMF is 7:3, the surface of the nanofiber shrinks towards the inside of the nanofiber, and no obvious pore is generated. Thus, in CF: when the ratio of DMF is 9:1, the diameter distribution and the shape of the fiber are most ideal.

FIG. 4 shows the fiber morphology of different amounts of PLA/CS chitosan. As shown in (a), (b) and (c) of fig. 4, as the CS content increases, the fiber surface pore structure is not significant, and thus only 1 wt% of chitosan by mass was selected for the subsequent study, i.e., PLA: CS ═ 7:1 (the result shown in (a) of fig. 4). As shown in FIG. 4 (d), when a trace amount of aloin was added, it did not greatly affect the morphology of PLA/CS fibers.

Diameter size analysis: and randomly extracting 100 fibers from 5 electron micrographs of each shot sample, measuring the diameter distribution of the fibers by using Image J software, and solving the average value, the standard deviation and the confidence interval of the diameter distribution. As shown in fig. 5, it can be seen that as the DMF content increases, the fiber diameter decreases and the uniformity of the fiber improves. As shown in (a), (b) and (c) of fig. 4, as the CS content increases, the average diameter of the PLA/CS porous nanofibers tends to increase, and the uniformity of the fiber diameter distribution decreases due to the decrease in conductivity due to the increase in viscosity of the PLA/CS spinning solution. And as shown in fig. 4 (a) and (d), the components PLA/CS and PLA/CS/Aloin fibers have similar diameters, but the fibers have improved uniformity when added with Aloin.

Example 3:

the yields of pure polylactic acid nanofibers, polylactic acid/chitosan nanofibers and polylactic acid/chitosan/aloin nanofibers prepared from different solutions were analyzed.

When the component is pure PLA, different solvent ratios have influence on the yield of the fiber, the DMF content is increased, the conductivity of the spinning solution is increased, the viscosity is reduced, and the yield of the fiber is correspondingly increased. When a certain amount of chitosan is added, the conductivity and viscosity of the spinning solution are influenced, the yield is reduced but still more than 20g/h, and the practical production application of the prepared nanofiber can be realized. The spinning solution after the addition of the minor amount of aloin had a viscosity and conductivity similar to those before the addition, and therefore its yield was similar to that of PLA/CS (90/10). Specific results are shown in table 2.

TABLE 2

Components	CF/DMF	Yield (g/h)
			PLA	80/20	36.16±1.32
PLA	90/10	25.28±3.08
			PLA/CS	90/10	23.34±7.04

Example 4:

and detecting the performance indexes of the pure polylactic acid nano fiber, the polylactic acid/chitosan nano fiber and the polylactic acid/chitosan/aloin nano fiber membrane for detecting the water vapor transmission rate, the contact angle and the swelling degree of the pure polylactic acid nano fiber, the polylactic acid/chitosan nano fiber and the polylactic acid/chitosan/aloin nano fiber prepared from different solutions. The results are shown in Table 3.

TABLE 3

The calculation results are shown in table 3, and all nanofiber membranes have contact angles larger than 90 ° due to the high proportion of PLA, and are all hydrophobic materials. For pure PLA nanofiber membranes, the contact angle of the surface porous nanofibers (PLA (90/10)) is higher than that of the surface nonporous nanofibers (PLA (80/20)), because the pore structure on the nanofiber surface can further expand the specific surface area and enhance the hydrophobic property. In addition, the porosity of porous PLA nanofibers is higher than that of non-porous PLA nanofibers, and the porosity of PLA/CS and PLA/CS/Aloin nanofibers are similar.

The water vapor transmission rate of the prepared nanofiber membrane is 2000-2500g/m 2/day. The water vapor transmission rate of the porous PLA nanofiber membrane (PLA (90/10)) is similar to that of the surface nonporous nanofiber membrane (PLA (80/20)), but the water vapor transmission rate of the porous PLA nanofiber membrane is relatively stable. The water vapor transmission rate of the pure PLA nanofiber membrane is lower than that of the PLA/CS and PLA/CS/aloin nanofiber membranes. Due to the addition of hydrophilic chitosan and aloe, the permeability of water vapor to the membrane is enhanced, so that the water vapor transmission rate of the fiber membrane is increased. In addition, the swelling capacity of porous PLA fibers is significantly higher than the porosity of non-porous PLA fibers, and the swelling capacities of PLA/CS and PLA/CS/Aloin nanofibers are also similar.

Example 5:

and (3) detecting the antibacterial performance of the polylactic acid/chitosan nano fiber and the polylactic acid/chitosan/aloin nano fiber prepared from different solutions.

The method is used for detecting the antibacterial performance of the fiber membrane prepared from cotton, polylactic acid/chitosan nanofiber and polylactic acid/chitosan/aloin nanofiber on Staphylococcus aureus (Staphylococcus aureus) and Escherichia coli (Escherichia coli), and specifically comprises the following steps:

preparing an agar culture medium and a liquid culture medium:

and (3) sterilization: test tubes, culture dishes, measuring cylinders, pipette tips and bacterial culture media and agar culture media used in the antibacterial experiments need to be sterilized by high-pressure steam before use. The specific operation is as follows: wrapping glassware with newspaper, sealing the culture medium with silica gel plug, wrapping the bottle mouth with newspaper, sterilizing in high pressure steam sterilizing pot at 103KPa and 125 deg.C for 30 hr, placing all the utensils on clean operating table, and sterilizing with ultraviolet lamp for 30 min.

Culturing a bacterial liquid: one ring of bacteria was taken from each slant of a 3-10 generation tube of bacteria (Staphylococcus aureus, Escherichia coli) with an inoculating loop, streaked on an agar plate, and cultured at 37 ℃ for 18-24 hours. Typical single colonies picked out from the plate by using the inoculating loop are respectively inoculated into 10mL test tube bacterial culture solution, and shake culture is carried out at 37 ℃ and 130rpm for 18-24h to obtain bacterial suspension. The number of colonies in the prepared bacterial suspension is large, and the cell concentration needs to be adjusted to be 1 × 109-5 × 109CFU/ml by a dilution method. Then sucking 2-3 ml (taking lower limit for escherichia coli and upper limit for staphylococcus aureus) and adding into 9ml broth to mix evenly, then taking 1ml and adding into another test tube filled with 9ml nutrient broth to mix evenly, then taking 1ml and adding into a test tube filled with 9ml PBS buffer solution to mix evenly, and diluting until the number of viable bacteria is 3X 105-5X 105 CFU/ml.

Contacting a sample with a bacterial liquid: 0.15g of the two nanofiber membrane samples and cotton were cut into 5mm × 5mm standard sizes, placed in triangular flasks containing 14ml of PBS buffer and 1ml of bacterial suspension was added. The Erlenmeyer flask is placed into a constant temperature oscillator at 25 ℃ and is shaken at 300rpm for 18-24 h.

Pouring a plate: after a predetermined time, 1ml of the shaken solution was taken out from the Erlenmeyer flask, transferred to a test tube containing 9ml of PBS buffer, and mixed well. Diluting to appropriate times by 10 times dilution method, transferring 1ml of diluent to sterilized plate, pouring 10-15ml of agar, solidifying at room temperature, culturing in 37 deg.C constant temperature incubator for 24 hr, and counting viable bacteria on the plate.

Calculating the bacteriostatic rate: the experimental results take the bacteriostatic rate as a standard, the bacteriostatic rate refers to the following formula, and the calculation results are shown in table 4.

R＝(N-N₀)/N

Wherein: r is the bacteriostasis rate, N is the colony count (CFU/ml) of a standard blank control group after being contacted with bacteria for a certain time, and N is₀The number of colonies (CFU/ml) after the fiber membrane was in contact with the bacteria for a certain period of time.

TABLE 3 antimicrobial Properties of the nanofibers

As shown in Table 3, the polylactic acid/chitosan nanofiber membrane has a low antibacterial effect on Escherichia coli and a low antibacterial effect on Staphylococcus aureus. After aloin is added, the bacteriostatic effect on escherichia coli and staphylococcus aureus is obvious and reaches 99.99 percent.

In summary, the following steps: the polylactic acid, the chitosan and the aloin are dissolved in the solvent to prepare a spinning solution, and the prepared nano fiber has uniform diameter and larger specific surface area occupied by gaps, so that the hydrophobic property of the nano fiber is enhanced; meanwhile, the hydrophilic chitosan and the aloin can enhance the permeability of water vapor to the nano fibers, so that the water vapor transmission rate of the nano fibers is increased, the wound is protected, and the healing of the wound can be promoted

The above is only one specific embodiment of the present application, and any other modifications based on the concept of the present application are considered as the protection scope of the present application.

Claims

1. A preparation method of antibacterial nano-fibers is characterized by comprising the following steps:

2. The method of claim 1, wherein the solvent comprises chloroform and N, N-dimethylformamide in a ratio ranging from 10:0 to 6: 4.

3. The method of claim 2, wherein the ratio of chloroform to N, N-dimethylformamide is in the range of 9: 1.

4. The method of claim 1, wherein the receiving member includes a receiving body rotating about a rotation axis and a driving body driving the receiving body to rotate.

5. The method of claim 4, wherein the receiving body is cylindrical, the cylindrical receiving body having an outer surface, the outer surface being the receiving surface.

6. The method of claim 1, wherein the reservoir has a recess having a bottom surface that is arcuate in cross-section.

7. An antibacterial nanofiber, characterized by being prepared by the method for preparing the antibacterial nanofiber as claimed in any one of claims 1 to 6.