Electrospun growth factor-loaded dressings and methods of making the same

Abstract

The application discloses a growth factor-loaded electrospun dressing, characterized by comprising the following components in percentage by mass: 55-85% of synthetic polymer, 9.5-36.4% of chitosan, 3.3-13.5% of bovine serum albumin, 0.07-0.14% of sodium triphosphate, 0.004-0.063% of basic fibroblast growth factor, and the rest being water, wherein the total of the percentage by mass of the above components is 100%. The growth factor-loaded electrospun dressing solves the problems of poor cell affinity and lack of cell climbing sites of smooth electrospun fiber dressing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of dressing forming, and particularly relates to a growth factor-loaded electrospun dressing and a preparation method of the growth factor-loaded electrospun dressing. BACKGROUND

[0002] The fiber membrane prepared by electrospinning technology has become a widely used wound dressing. The electrospun dressing has high porosity, small pore size and a structure similar to the extracellular matrix, and thus has excellent bacteria isolation and air permeability, and can provide a good healing environment for a wound. However, the electrospun dressing with a single component has poor cell affinity, lacks sites for promoting cell proliferation and adhesion, and has limited promotion effect on wound healing. Cell growth factors are a kind of polypeptide substances with cell growth stimulating activity. Loading the growth factors on the electrospun dressing can significantly enhance the cell affinity and healing promotion capacity of the dressing, thereby achieving the treatment of serious skin damage such as burns, wounds, inflammation and ulceration. The growth factors have poor stability and short in-vivo half-life. Uniform distribution of the growth factors on the fibers and sustained release to form cell climbing points are the key to improving the healing promotion performance of the growth factor-loaded electrospun dressing.

[0003] At present, the means for preparing the growth factor-loaded electrospun dressing mainly includes two types. One is to mix the growth factors with a polymer solution and then electrospun. The growth factors are mostly attached to the surface of the fibers, and about 80% of the growth factors are released within the first 24 hours, which is not conducive to the sustained promotion of cell proliferation. The other is to use emulsion electrospinning technology to prepare fibers with a core-shell structure. The core-shell fiber will have a burst release of 20%-30% of the growth factors within the first 24 hours. Therefore, the growth factor loading amount should not be too high, so as to result in low sustained release amount and poor cell affinity. The fiber surfaces prepared by the two methods are smooth, the growth factors are arranged and dispersed, and the release is not stable, and it is difficult to form cell climbing points. SUMMARY

[0004] The first object of the present application is to provide a growth factor-loaded electrospun dressing, which solves the problems of poor cell affinity and lack of cell climbing sites of the smooth electrospun fiber dressing.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a growth factor-loaded electrospun dressing, which is composed of the following components in mass percentage: synthetic polymer 55%-85%, chitosan 9.5%-36.4%, bovine serum albumin 3.3%-13.5%, sodium tripolyphosphate 0.07%-0.14%, basic fibroblast growth factor 0.004%-0.063%, and the rest is water, and the mass percentage of the above components is 100%.

[0006] The technical solution of the present invention also has the following characteristics:

[0007] As a preferred technical solution of the present invention, the synthetic polymer is one or more of polylactic acid, polycaprolactone, and polyurethane.

[0008] As a preferred technical solution of the present invention, the screening mechanism further includes a feed hopper, the molecular weight of the chitosan is 15w-25w, and the degree of deacetylation is above 80%.

[0009] The second purpose of the present invention is to provide a method for preparing an electrospun dressing loaded with growth factors, so as to solve the problem that smooth electrospun fiber dressings have poor cell affinity and lack cell climbing sites.

[0010] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a method for preparing an electrospinning dressing loaded with growth factors, which is specifically implemented according to the following steps:

[0011] Step 1: preparing a solvent by mixing acetone and dichloromethane at a volume ratio of 1:3-5, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; the electrospinning scaffold solution has a mass concentration of 8%-12% of the synthetic polymer and a mass concentration of 0.01%-0.02% of the sodium tripolyphosphate;

[0012] Step 2: preparing an anionic scaffold uniformly loaded with sodium tripolyphosphate by electrospinning the electrospinning scaffold solution of step 1 above;

[0013] Step 3, dissolving chitosan in an acetic acid solution having a volume fraction of 2%-3% to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 1.5%-2.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 0.8%-1.2%, and the mass concentration of growth factor is 0.001%-0.003%; and separately preparing a sodium hydroxide solution having a mass concentration of 1%-2%;

[0014] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH is then adjusted to 7-8 using acetic acid to obtain a scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution is 1:1-2; the volume ratio of the chitosan solution to the sodium hydroxide solution is 1:1-2.

[0015] Step 5. The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 30mL-40mL; then, the anionic scaffold is rinsed with deionized water 2-4 times, and freeze-dried at -40°C to -50°C and a vacuum degree of 10MPa-20MPa for 3h-5h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0016] The technical solution of the present invention also has the following characteristics:

[0017] As a preferred technical solution of the present invention, in step 2, the electrospinning conditions are voltage 15kV-25kV, temperature 25℃-30℃, humidity 30%-40%, spinning rate 1mL / h-2mL / h, the distance from the needle to the receiving end is 8cm-14cm, and the receiving end is a metal electrode.

[0018] As a preferred technical solution of the present invention, in step 2 and step 4, the conditions for electrostatic spraying are voltage 10kV-20kV, temperature 25°C-30°C, humidity 30%-40%, spinning rate 1.5mL / h-3mL / h, and the distance from the needle to the bottom of the receiving solution is 9cm-12cm.

[0019] The beneficial effects of the present invention are as follows: the electrospinning dressing loaded with growth factor cell climbing points of the present invention has better cell affinity, a smooth cumulative growth factor release curve, a release period of up to 72 hours, and can better promote cell proliferation and attachment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron microscope image of the electrospun dressing of the present invention after gold spraying.

[0021] Figure 2 The adsorption rates of the anionic scaffold without cell climbing sites and the electrospun dressing of the present invention with different amounts of cell climbing sites on rabbit red blood cells are shown.

[0022] Figure 3 These are sample images of the rabbit red blood cell adsorption experiment using anionic scaffolds without cell climbing sites and electrospun dressings of the present invention with different amounts of cell climbing sites.

[0023] Figure 4 This is a comparison chart of the growth factor release behavior of the electrospun dressing of the present invention and the electrospun dressing loaded with growth factors in the prior art. DETAILED DESCRIPTION

[0024] The invention discloses an electrospun dressing loaded with growth factors, which is composed of the following components by mass percentage: 55%-85% synthetic polymer, 9.5%-36.4% chitosan, 3.3%-13.5% bovine serum albumin, 0.07%-0.14% sodium tripolyphosphate, 0.004%-0.063% basic fibroblast growth factor, and the remainder being water, with the mass percentages of the above components totaling 100%. The synthetic polymer is one or more of polylactic acid, polycaprolactone, and polyurethane. The molecular weight of the chitosan is 15w-25w, and the degree of deacetylation is above 80%.

[0025] The preparation method of the growth factor-loaded electrospun dressing is specifically implemented according to the following steps:

[0026] Step 1: preparing a solvent by mixing acetone and dichloromethane at a volume ratio of 1:3-5, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; the electrospinning scaffold solution has a mass concentration of 8%-12% of the synthetic polymer and a mass concentration of 0.01%-0.02% of the sodium tripolyphosphate;

[0027] Step 2: The electrospinning scaffold solution of step 1 is electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions are voltage 15kV-25kV, temperature 25°C-30°C, humidity 30%-40%, spinning rate 1mL / h-2mL / h, the distance from the needle to the receiving end is 8cm-14cm, and the receiving end is a metal electrode;

[0028] Step 3, dissolving chitosan in an acetic acid solution having a volume fraction of 2%-3% to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 1.5%-2.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 0.8%-1.2%, and the mass concentration of growth factor is 0.001%-0.003%; and separately preparing a sodium hydroxide solution having a mass concentration of 1%-2%;

[0029] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, select sodium hydroxide solution as the liquid receiving device for electrostatic spraying, and then use acetic acid to adjust the pH to 7-8 to obtain the scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution is 1:1-2; the volume ratio of the chitosan solution to the sodium hydroxide solution is 1:1-2; the conditions for electrostatic spraying are voltage 10kV-20kV, temperature 25℃-30℃, humidity 30%-40%, spinning rate 1.5mL / h-3mL / h, and the distance from the needle to the bottom of the receiving solution is 9cm-12cm;

[0030] Step 5. The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 30mL-40mL; then, the anionic scaffold is rinsed with deionized water 2-4 times, and freeze-dried at -40°C to -50°C and a vacuum degree of 10MPa-20MPa for 3h-5h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0031] Example 1

[0032] The electrospun dressing loaded with growth factors of the present invention is composed of the following components by mass percentage: 72.7% synthetic polymer, 20.3% chitosan, 6.7% bovine serum albumin, 0.11% sodium tripolyphosphate, 0.013% basic fibroblast growth factor, and the remainder being water, and the total mass percentage of the above components is 100%.

[0033] The preparation method of the growth factor-loaded electrospinning dressing of the present invention is specifically implemented according to the following steps:

[0034] Step 1: preparing a solvent by mixing acetone and dichloromethane in a volume ratio of 1:4, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; wherein the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 10%, and the mass concentration of the sodium tripolyphosphate is 0.015%;

[0035] Step 2: The electrospinning scaffold solution of step 1 was electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions were voltage 20 kV, temperature 28°C, humidity 35%, spinning rate 1.5 mL / h, the distance from the needle to the receiving end was 11 cm, and the receiving end was a metal electrode;

[0036] Step 3, dissolving chitosan in a 2.5% by volume acetic acid solution to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 2%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 1%, and the mass concentration of growth factor is 0.002%; and separately preparing a sodium hydroxide solution with a mass concentration of 1.5%;

[0037] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH was then adjusted to 7.5 with acetic acid to obtain the scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution was 2:3; the volume ratio of the chitosan solution to the sodium hydroxide solution was 2:3. The electrostatic spraying conditions were 15 kV, 28°C, 35% humidity, a spinning rate of 2.5 mL / h, and a distance of 10 cm from the needle to the bottom of the receiving solution.

[0038] Step 5: The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 35mL; then, the anionic scaffold is rinsed with deionized water three times, and freeze-dried at -45°C and a vacuum degree of 15MPa for 4h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0039] Example 2

[0040] The electrospun dressing loaded with growth factors of the present invention is composed of the following components in percentage by mass: 57% synthetic polymer, 28.7% chitosan, 13.5% bovine serum albumin, 0.07% sodium tripolyphosphate, 0.03% basic fibroblast growth factor, and the remainder being water, with the total percentage by mass of the above components being 100%.

[0041] The preparation method of the growth factor-loaded electrospun dressing is specifically implemented according to the following steps:

[0042] Step 1: preparing a solvent by mixing acetone and dichloromethane in a volume ratio of 1:3, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; wherein the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 8%, and the mass concentration of the sodium tripolyphosphate is 0.01%;

[0043] Step 2: The electrospinning scaffold solution of step 1 was electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions were voltage 15 kV, temperature 25°C, humidity 30%, spinning rate 1 mL / h, the distance from the needle to the receiving end was 8 cm, and the receiving end was a metal electrode;

[0044] Step 3, dissolving chitosan in a 2% by volume acetic acid solution to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 2.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 1.2%, and the mass concentration of growth factor is 0.003%; and separately preparing a sodium hydroxide solution with a mass concentration of 1%;

[0045] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH was then adjusted to 7 with acetic acid to obtain a scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution was 1:1; the volume ratio of the chitosan solution to the sodium hydroxide solution was 1:1. The electrostatic spraying conditions were a voltage of 10 kV, a temperature of 25°C, a humidity of 30%, a spinning rate of 1.5 mL / h, and a distance of 9 cm from the needle to the bottom of the receiving solution.

[0046] Step 5: The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 40mL; then, the anionic scaffold is rinsed with deionized water twice, and freeze-dried at -40°C and a vacuum degree of 10MPa for 3h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0047] Example 3

[0048] The invention is composed of the following components: 83.5% of synthetic polymer, 12.5% ​​of chitosan, 3.3% of bovine serum albumin, 0.14% of sodium tripolyphosphate, 0.004% of basic fibroblast growth factor, and the remainder is water, and the total weight percentage of the above components is 100%.

[0049] The preparation method of the growth factor-loaded electrospun dressing is specifically implemented according to the following steps:

[0050] Step 1: preparing a solvent by mixing acetone and dichloromethane in a volume ratio of 1:5, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; wherein the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 12%, and the mass concentration of the sodium tripolyphosphate is 0.02%;

[0051] Step 2: The electrospinning scaffold solution of step 1 was electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions were voltage 25 kV, temperature 30°C, humidity 40%, spinning rate 2 mL / h, the distance from the needle to the receiving end was 14 cm, and the receiving end was a metal electrode;

[0052] Step 3, dissolving chitosan in a 3% by volume acetic acid solution to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 1.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 0.8%, and the mass concentration of growth factor is 0.001%; ​​and separately preparing a sodium hydroxide solution with a mass concentration of 2%;

[0053] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH was then adjusted to 8 with acetic acid to obtain a scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution was 1:2; the volume ratio of the chitosan solution to the sodium hydroxide solution was 1:2. The electrostatic spraying conditions were 20 kV, 30°C, 40% humidity, a spinning rate of 3 mL / h, and a distance of 12 cm from the needle to the bottom of the receiving solution.

[0054] Step 5. The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 40mL; then, the anionic scaffold is rinsed with deionized water 4 times, and freeze-dried at -50°C and a vacuum degree of 20MPa for 5h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0055] Example 4

[0056] The invention discloses an electrospun dressing loaded with growth factors, which is composed of the following components by mass percentage: 85% synthetic polymer, 9.5% chitosan, 5% bovine serum albumin, 0.14% sodium tripolyphosphate, 0.063% basic fibroblast growth factor, and the remainder being water, with the total mass percentage of the above components being 100%.

[0057] The preparation method of the growth factor-loaded electrospun dressing is specifically implemented according to the following steps:

[0058] Step 1: preparing a solvent by mixing acetone and dichloromethane in a volume ratio of 1:5, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; wherein the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 12%, and the mass concentration of the sodium tripolyphosphate is 0.02%;

[0059] Step 2: The electrospinning scaffold solution of step 1 was electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions were voltage 25 kV, temperature 30°C, humidity 40%, spinning rate 2 mL / h, the distance from the needle to the receiving end was 14 cm, and the receiving end was a metal electrode;

[0060] Step 3, dissolving chitosan in a 3% by volume acetic acid solution to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 1.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 0.8%, and the mass concentration of growth factor is 0.001%; ​​and separately preparing a sodium hydroxide solution with a mass concentration of 2%;

[0061] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH was then adjusted to 8 with acetic acid to obtain a scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution was 1:1; the volume ratio of the chitosan solution to the sodium hydroxide solution was 1:2. The electrostatic spraying conditions were 20 kV, 30°C, 40% humidity, a spinning rate of 3 mL / h, and a distance of 12 cm from the needle to the bottom of the receiving solution.

[0062] Step 5: The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 30mL; then, the anionic scaffold is rinsed with deionized water 4 times, and freeze-dried at -50°C and a vacuum degree of 20MPa for 5h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0063] Example 5

[0064] The electrospun dressing loaded with growth factors of the present invention is composed of the following components in percentage by mass: 55% synthetic polymer, 36.4% chitosan, 8.5% bovine serum albumin, 0.07% sodium tripolyphosphate, 0.02% basic fibroblast growth factor, and the remainder being water, with the total percentage by mass of the above components being 100%.

[0065] The preparation method of the growth factor-loaded electrospun dressing is specifically implemented according to the following steps:

[0066] Step 1: preparing a solvent by mixing acetone and dichloromethane in a volume ratio of 1:3, dissolving a synthetic polymer in the solvent, and then adding sodium tripolyphosphate and mixing to obtain an electrospinning scaffold solution; wherein the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 8%, and the mass concentration of the sodium tripolyphosphate is 0.01%;

[0067] Step 2: The electrospinning scaffold solution of step 1 was electrospinned to prepare an anionic scaffold uniformly loaded with sodium tripolyphosphate; the electrospinning conditions were voltage 15 kV, temperature 25°C, humidity 30%, spinning rate 1 mL / h, the distance from the needle to the receiving end was 8 cm, and the receiving end was a metal electrode;

[0068] Step 3, dissolving chitosan in a 2% by volume acetic acid solution to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 2.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 1.2%, and the mass concentration of growth factor is 0.003%; and separately preparing a sodium hydroxide solution with a mass concentration of 1%;

[0069] Step 4: After mixing the chitosan solution prepared in step 3 above with the mixed solution, electrostatically spray the solution using sodium hydroxide solution as the liquid receiving device. The pH was then adjusted to 7 with acetic acid to obtain a scaffold precursor solution. The volume ratio of the mixed solution to the chitosan solution was 1:2; the volume ratio of the chitosan solution to the sodium hydroxide solution was 1:1. The electrostatic spraying conditions were a voltage of 10 kV, a temperature of 25°C, a humidity of 30%, a spinning rate of 1.5 mL / h, and a distance of 9 cm from the needle to the bottom of the receiving solution.

[0070] Step 5: The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 40mL; then, the anionic scaffold is rinsed with deionized water twice, and freeze-dried at -40°C and a vacuum degree of 10MPa for 3h to obtain an electrospun dressing loaded with growth factor cell climbing points.

[0071] Figure 1 This is a scanning electron microscope image of the electrospun dressing of the present invention after gold spraying. Chitosan particles loaded with growth factors are evenly dispersed on the surface of the anionic scaffold as cell climbing points.

[0072] Figure 2 The adsorption rates of rabbit red blood cells by the electrospun dressings of the present invention, which were loaded with growth factor-loaded cell-climbing sites, were shown for anionic scaffolds without cell-climbing sites and those loaded with different cell-climbing sites. Compared to the anionic scaffolds without cell-climbing sites, the electrospun dressings loaded with growth factor-loaded cell-climbing sites showed significantly higher cell adsorption rates, and this increased with increasing cell-climbing site content, demonstrating that the present invention significantly enhances the dressing's cell affinity.

[0073] Figure 3 The images show rabbit red blood cell adsorption experiments on anionic scaffolds without cell-climbing sites and electrospun dressings of the present invention with varying amounts of cell-climbing sites. The dressings with cell-climbing sites showed a significant increase in red blood cell adsorption, and the amount of adsorbed red blood cells increased with increasing levels of climbing sites, demonstrating the present invention's improved cell affinity.

[0074] Figure 4 The figure compares the growth factor release behavior of the electrospun dressing of the present invention and the electrospun dressing loaded with growth factors in the prior art. The electrospun dressing loaded with growth factor cell climbing sites of the present invention can achieve a 72-hour steady release of growth factors.

[0075] The present invention uses ionic crosslinking technology to evenly anchor growth factor-encapsulated chitosan microspheres onto an electrospun polymer fiber scaffold, achieving long-term, stable release of the growth factors and forming climbing sites that promote cell proliferation. This significantly improves the cell affinity of the electrospun dressing.

[0076] The present application prepares an anion support by electrospinning technology, and under the action of high-voltage electric field, the organic solvent of the polymer solution mixed with sodium tripolyphosphate is volatilized, the polymer is refined and stretched to form fibers, and the sodium tripolyphosphate is uniformly distributed on the fibers. The support precursor solution is prepared by electrostatic spraying technology, and the chitosan colloidal particles loaded with cell growth factors are formed in the precursor solution. When the support precursor solution passes through the anion support at a constant flow, the sodium tripolyphosphate and the chitosan colloidal particles in the precursor solution are ionically cross-linked to anchor on the anion support to form cell climbing sites. The growth factors at the climbing sites are slowly released, and the cells are adsorbed to the climbing sites for proliferation, thereby significantly enhancing the cell affinity and healing-promoting ability of the dressing.

[0077] The electrospun dressing of the present application loaded with growth factor cell climbing points is observed by scanning electron microscopy (SEM) after spraying gold. As shown in Figure 1 , the chitosan colloidal particles loaded with growth factors in the precursor solution are uniformly dispersed on the surface of the anion support as cell climbing points.

[0078] The anion support and the electrospun dressing combined with different amounts of cell climbing sites are subjected to cell adsorption experiments with rabbit red blood cells in a 24-well plate. The experimental results are shown in Figure 2 , which show that the cell adsorption rate increases significantly with the increase of the number of cell climbing points, that is, the cell affinity of the support is significantly improved with the increase of the number of cell climbing points.

[0079] The adhesion of rabbit red blood cells on the surface of the dressing after incubation is shown in Figure 3 , and the number of red blood cells adsorbed by the electrospun dressing combined with cell climbing points is significantly increased compared with the anion support without loading cell climbing points. And with the increase of the amount of cell climbing points combined, the number of red blood cells adsorbed by the dressing also increases significantly.

[0080] As shown in Figure 4 , the cumulative release results in PBS buffer at 37℃ and pH 7.2 show that the growth factor release of the electrospun dressing loaded with growth factors of the present application is more stable, and the sustained release time is longer.

[0081] Therefore, the electrospun dressing loaded with growth factor cell climbing points of the present application has more stable growth factor release, and has better cell affinity.

Claims

1. A method for preparing an electrospinning dressing loaded with growth factors, characterized in that: The electrospun dressing loaded with growth factors is composed of the following components by mass percentage: 55%-85% synthetic polymer, 9.5%-36.4% chitosan, 3.3%-13.5% bovine serum albumin, 0.07%-0.14% sodium tripolyphosphate, 0.004%-0.063% basic fibroblast growth factor, and the remainder being water, with the total mass percentage of the above components being 100%; the synthetic polymer is one or more of polylactic acid, polycaprolactone, and polyurethane; the chitosan has a molecular weight of 15w-25w and a degree of deacetylation of more than 80%; Please follow the steps below to implement it: Step 1: Acetone and dichloromethane are prepared in a volume ratio of 1:3-5 to obtain a solvent, a synthetic polymer is dissolved in the solvent, and sodium tripolyphosphate is added and mixed to obtain an electrospinning scaffold solution; the mass concentration of the synthetic polymer in the electrospinning scaffold solution is 8%-12%, and the mass concentration of sodium tripolyphosphate is 0.01%-0.02%; Step 2: preparing an anionic scaffold uniformly loaded with sodium tripolyphosphate by electrospinning the electrospinning scaffold solution of step 1 above; Step 3, dissolving chitosan in an acetic acid solution having a volume fraction of 2%-3% to obtain a chitosan solution, wherein the mass concentration of chitosan in the chitosan solution is 1.5%-2.5%; dissolving bovine serum albumin and growth factor in deionized water to obtain a mixed solution, wherein the mass concentration of bovine serum albumin in the mixed solution is 0.8%-1.2%, and the mass concentration of growth factor is 0.001%-0.003%; and separately preparing a sodium hydroxide solution having a mass concentration of 1%-2%; Step 4: After the chitosan solution prepared in step 3 is mixed with the mixed solution, a sodium hydroxide solution is selected as a liquid receiving device for electrostatic spraying, and then the pH is adjusted to 7-8 with acetic acid to obtain a scaffold precursor solution; the volume ratio of the mixed solution to the chitosan solution is 1:1-2; the volume ratio of the chitosan solution to the sodium hydroxide solution is 1:1-2; Step 5. The scaffold precursor solution prepared in step 4 is passed through the anionic scaffold prepared in step 2 at a constant flow rate until the chitosan-encapsulated growth factor is condensed into cell climbing points on the anionic scaffold. The volume of the scaffold precursor solution passing through each 1g of the anionic scaffold is 30mL-40mL; then, the anionic scaffold is rinsed with deionized water 2-4 times, and freeze-dried at -40°C to -50°C and a vacuum degree of 10MPa-20MPa for 3h-5h to obtain an electrospun dressing loaded with growth factor cell climbing points.

2. The method for preparing the growth factor-loaded electrospinning dressing according to claim 1, characterized in that: In step 2, the electrospinning conditions are voltage 15kV-25kV, temperature 25°C-30°C, humidity 30%-40%, spinning rate 1mL / h-2mL / h, the distance from the needle to the receiving end is 8cm-14cm, and the receiving end is a metal electrode.

3. The method for preparing the growth factor-loaded electrospinning dressing according to claim 2, characterized in that: In step 4, the conditions for electrostatic spraying are voltage 10 kV-20 kV, temperature 25° C.-30° C., humidity 30%-40%, spinning rate 1.5 mL / h-3 mL / h, and the distance from the needle to the bottom of the receiving solution is 9 cm-12 cm.

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