A medical surgical dressing and a method of making the same

Abstract

In order to improve the biocompatibility of the medical surgical dressing, the present application introduces titanium dioxide to the surface of the sponge-like chitosan dressing. Since titanium dioxide has good biocompatibility, the overall biocompatibility of the chitosan dressing is improved. On the other hand, titanium dioxide itself has good antibacterial ability, so the problem of unsatisfactory biocompatibility of Zn antibacterial agent and the high price of Ag antibacterial agent in the prior art is overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of surgical dressings, in particular to a medical surgical dressing and a preparation method thereof. BACKGROUND

[0002] Medical dressings are medical materials used for temporarily covering the surface of various wounds. An ideal medical dressing should have the following functions: ① It can be closely attached to the wound surface and have good affinity; ② It can prevent the loss of body fluids and moisture; ③ It can resist the invasion of bacteria and prevent infection; ④ It can relieve pain; ⑤ It has good air permeability, moisture retention and biocompatibility.

[0003] Natural high molecular chitosan has good physicochemical properties and biological activity, is biodegradable and has non-toxic and harmless degradation products, and has been widely used in the field of medical dressings. In the prior art, silver and / or zinc oxide are loaded on the surface of chitosan to improve the antibacterial ability of the dressing. However, silver is expensive, and the biocompatibility of ZnO is not satisfactory, which are problems urgently needed to be solved in the field of dressings. SUMMARY

[0004] In view of the problems existing in the prior art, the purpose of the present application is to provide a preparation method of a medical surgical dressing, which has excellent antibacterial ability and biocompatibility.

[0005] A preparation method of a medical surgical dressing, comprising the following steps:

[0006] Take 1-3 g of chitosan powder, add 50-80 mL of 1.5-1.8 wt% acetic acid solution, stir until completely dissolved, obtain a chitosan-acetic acid solution, pour the solution into a twelve-hole plate, and pre-freeze at low temperature; after complete freezing, move to a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product; immerse the intermediate product in 1.5-1.8 M ammonia water to remove the residual acetic acid on the surface; after soaking for 2.5-3 h, take it out, wash it repeatedly with deionized water several times until the washing liquid is free of alkaline components, then squeeze the water out of the dressing, pre-freeze again at low temperature, and perform secondary freeze-drying after the solution is completely frozen to obtain a sponge-like chitosan dressing;

[0007] Place the chitosan dressing in a sputtering film coating machine, use TiO2 as the sputtering target material, and inert gas as the working gas, uniformly sputter TiO2 on the surface of the chitosan dressing, and adjust the sputtering time so that the mass of TiO2 is 0.8-4.5% of the total mass of the dressing.

[0008] Preferably, the pre-freezing temperature is -25°C.

[0009] Preferably, the concentration of the ammonia water is 1.5 M.

[0010] Preferably, the concentration of the acetic acid solution is 1.5%.

[0011] Preferably, the inert gas is argon.

[0012] Preferably, the soaking time is 2.5h.

[0013] Preferably, the sputtering is magnetron sputtering.

[0014] Further, the present application also provides a medical surgical dressing prepared by the above method.

[0015] In order to improve the biocompatibility of the medical surgical dressing, the present application introduces titanium dioxide to the surface of the sponge-like chitosan dressing. Since titanium dioxide has good biocompatibility, this improves the overall biocompatibility of the chitosan dressing. On the other hand, titanium dioxide itself has good antibacterial ability, so it overcomes the problems of unsatisfactory biocompatibility of Zn antibacterial agent and expensive price of Ag antibacterial agent in the prior art. DETAILED DESCRIPTION

[0016] The technical effects of the present application are verified by specific examples below, but the embodiments of the present application are not limited thereto.

[0017] Example 1

[0018] Take 1g of chitosan powder, add 50mL of acetic acid solution with a mass concentration of 1.5wt%, stir until completely dissolved, obtain a chitosan-acetic acid solution, pour the solution into a twelve-hole plate, and pre-freeze at -25℃. After complete freezing, transfer to a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product. Immerse the intermediate product in 1.5M ammonia water to remove the residual acetic acid on the surface. After soaking for 3h, take it out, wash repeatedly with deionized water several times until the washing liquid is free of alkaline components, then squeeze out the water of the dressing, pre-freeze again at -25℃, and after the solution is completely frozen, perform secondary freeze-drying to obtain a sponge-like chitosan dressing.

[0019] Place the chitosan dressing in a magnetron sputtering coating machine, use TiO2 as the sputtering target material, and argon as the working gas, uniformly sputter TiO2 onto the surface of the chitosan dressing, and by adjusting the sputtering time, make the mass of TiO2 0.8% of the total mass of the dressing.

[0020] Example 2

[0021] Take 1 g of chitosan powder, add 50 mL of 1.5 wt% acetic acid solution, stir until completely dissolved, get chitosan-acetic acid solution, pour the solution into twelve-hole plate, pre-freeze at-25℃. After completely frozen, move into vacuum freeze dryer for freeze-drying, get sponge-like chitosan dressing intermediate product. Immersed in 1.5M ammonia water to remove the residual acetic acid on the surface. After soaking for 3h, take out, wash with deionized water for several times until the washing liquid is free of alkaline ingredients, then squeeze the water out of the dressing, pre-freeze at-25℃ again, after the solution is completely frozen, carry out secondary freeze-drying, get sponge-like chitosan dressing.

[0022] The chitosan dressing is placed in a magnetron sputtering coating machine, TiO2 is used as the sputtering target material, argon is used as the working gas, and TiO2 is uniformly sputtered on the surface of the chitosan dressing. By adjusting the sputtering time, the mass of TiO2 is 1.5% of the total mass of the dressing.

[0023] Example 3

[0024] Take 1 g of chitosan powder, add 50 mL of 1.5 wt% acetic acid solution, stir until completely dissolved, get chitosan-acetic acid solution, pour the solution into twelve-hole plate, pre-freeze at-25℃. After completely frozen, move into vacuum freeze dryer for freeze-drying, get sponge-like chitosan dressing intermediate product. Immersed in 1.5M ammonia water to remove the residual acetic acid on the surface. After soaking for 3h, take out, wash with deionized water for several times until the washing liquid is free of alkaline ingredients, then squeeze the water out of the dressing, pre-freeze at-25℃ again, after the solution is completely frozen, carry out secondary freeze-drying, get sponge-like chitosan dressing.

[0025] The chitosan dressing is placed in a magnetron sputtering coating machine, TiO2 is used as the sputtering target material, argon is used as the working gas, and TiO2 is uniformly sputtered on the surface of the chitosan dressing. By adjusting the sputtering time, the mass of TiO2 is 2.1% of the total mass of the dressing.

[0026] Example 4

[0027] Take 1 g of chitosan powder, add 50 mL of 1.5 wt% acetic acid solution, stir until completely dissolved, get chitosan-acetic acid solution, pour the solution into twelve-hole plate, pre-freeze at-25℃. After completely frozen, move into vacuum freeze dryer for freeze-drying, get sponge-like chitosan dressing intermediate product. Immersed in 1.5M ammonia water to remove the residual acetic acid on the surface. After soaking for 3h, take out, wash with deionized water for several times until the washing liquid is free of alkaline ingredients, then squeeze the water out of the dressing, pre-freeze at-25℃ again, after the solution is completely frozen, carry out secondary freeze-drying, get sponge-like chitosan dressing.

[0028] The chitosan dressing was placed in a magnetron sputtering coater, TiO2 was used as the sputtering target, and argon was used as the working gas to uniformly sputter TiO2 on the surface of the chitosan dressing. The mass of TiO2 was adjusted to be 4.5% of the total mass of the dressing by adjusting the sputtering time.

[0029] Example 5

[0030] 1 g of chitosan powder was added to 50 mL of 1.5 wt% acetic acid solution, stirred until completely dissolved to obtain a chitosan-acetic acid solution, and then poured into a twelve-hole plate and pre-frozen at -25°C. After complete freezing, the solution was transferred to a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product. The intermediate product was immersed in 1.5 M ammonia water to remove the residual acetic acid on the surface. After soaking for 3 h, it was taken out and repeatedly washed with deionized water several times until the washing liquid was free of basic components. Then the water in the dressing was squeezed out, and the dressing was again pre-frozen at -25°C. After the solution was completely frozen, it was subjected to secondary freeze-drying to obtain a sponge-like chitosan dressing.

[0031] The chitosan dressing was placed in a magnetron sputtering coater, γ-Fe2O3 / TiO2 composite target was used as the sputtering target, and argon was used as the working gas to uniformly sputter TiO2 on the surface of the chitosan dressing. The mass of TiO2 was adjusted to be 1.2% of the total mass of the dressing, and the mass of γ-Fe2O3 was adjusted to be 0.9% of the total mass of the dressing by adjusting the sputtering time.

[0032] Example 6

[0033] 1 g of chitosan powder was added to 50 mL of 1.5 wt% acetic acid solution, stirred until completely dissolved to obtain a chitosan-acetic acid solution, and then poured into a twelve-hole plate and pre-frozen at -25°C. After complete freezing, the solution was transferred to a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product. The intermediate product was immersed in 1.5 M ammonia water to remove the residual acetic acid on the surface. After soaking for 3 h, it was taken out and repeatedly washed with deionized water several times until the washing liquid was free of basic components. Then the water in the dressing was squeezed out, and the dressing was again pre-frozen at -25°C. After the solution was completely frozen, it was subjected to secondary freeze-drying to obtain a sponge-like chitosan dressing.

[0034] The chitosan dressing was placed in a magnetron sputtering coater, γ-Fe2O3 / TiO2 composite target was used as the sputtering target, and argon was used as the working gas to uniformly sputter TiO2 on the surface of the chitosan dressing. The mass of TiO2 was adjusted to be 2.1% of the total mass of the dressing, and the mass of γ-Fe2O3 was adjusted to be 0.9% of the total mass of the dressing by adjusting the sputtering time.

[0035] Comparative Example 1

[0036] Take 1 g of chitosan powder, add 50 mL of 1.5 wt% acetic acid solution, stir until completely dissolved, to obtain a chitosan-acetic acid solution, pour the solution into a twelve-hole plate, and pre-freeze at -25°C. After complete freezing, move into a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product. Immerse the intermediate product in 1.5 M ammonia water to remove the residual acetic acid on the surface. After soaking for 3 h, remove and wash repeatedly with deionized water several times until the washing liquid is free of basic components, then squeeze out the water of the dressing, pre-freeze again at -25°C, and perform secondary freeze-drying after the solution is completely frozen to obtain a sponge-like chitosan dressing.

[0037] Place the chitosan dressing in a magnetron sputtering film coating machine, use ZnO as the sputtering target material, and argon as the working gas to uniformly sputter ZnO on the surface of the chitosan dressing. By adjusting the sputtering time, the mass of ZnO is 2.1% of the total mass of the dressing.

[0038] Comparative Example 2

[0039] Take 1 g of chitosan powder, add 50 mL of 1.5 wt% acetic acid solution, stir until completely dissolved, to obtain a chitosan-acetic acid solution, pour the solution into a twelve-hole plate, and pre-freeze at -25°C. After complete freezing, move into a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product. Immerse the intermediate product in 1.5 M ammonia water to remove the residual acetic acid on the surface. After soaking for 3 h, remove and wash repeatedly with deionized water several times until the washing liquid is free of basic components, then squeeze out the water of the dressing, pre-freeze again at -25°C, and perform secondary freeze-drying after the solution is completely frozen to obtain a sponge-like chitosan dressing.

[0040] Hereinafter, we evaluate the biocompatibility and antibacterial performance of the samples in Examples 1-6 and Comparative Examples 1-2, and the specific method is as follows:

[0041] Antibacterial performance: select 4 x 10 6 cfu / ml of Staphylococcus aureus as the test bacterial solution, and add 0.2 ml of the test bacterial solution to the surface of the sample, respectively, and incubate at 37°C under conditions of relative humidity RH > 90% for 48 h, then remove the sample and count the viable bacteria, and obtain the antibacterial rate by counting. Each sample is tested in quintuplicate. The antibacterial rate calculation formula is:

[0042] R(%) = (A-B) / A x 100

[0043] Where: R represents the antibacterial rate;

[0044] A represents the average number of recovered bacteria in the control group;

[0045] B represents the average recovery bacteria number of the example or the sample of the comparative example.

[0046] Biocompatibility: the biocompatibility of each sample was evaluated by hemolysis test, which was based on the principle that the sample was directly contacted with blood, and the amount of hemoglobin released after the rupture of red blood cell membrane was measured to detect the in vitro hemolysis degree of each sample. The absorption wavelength of hemoglobin was 545 nm, and the concentration thereof could be detected by spectrophotometer. The specific operation steps were as follows:

[0047] (1) After the healthy rabbits were anesthetized and fixed, 4 mL of venous blood was slowly extracted from the rabbit auricular vein, 0.2 mL of 2% potassium oxalate was added, and fresh anticoagulant blood was prepared. 5 mL of 0.9% sodium chloride injection was added for dilution.

[0048] (2) Three siliconized test tubes were taken, one test tube was filled with the test sample and sodium chloride injection 10 mL, one test tube was blank as the negative control group, and 10 mL of sodium chloride physiological saline was added, and the other test tube was blank as the positive control group, and 10 mL of distilled water was added respectively.

[0049] (3) All test tubes were incubated in a 37℃ water bath for 30 min, 0.2 mL of anticoagulant rabbit blood was added, and incubated at 37℃ for 60 min, and then centrifuged in a centrifuge at 1000 r / min for 5 min.

[0050] (4) The upper clear liquid of the test tube was taken, and the absorbance was measured at 545 nm. Each sample was tested in triplicate and the average value was taken.

[0051] The calculation formula of hemolysis rate is as follows:

[0052] Hemolysis rate (%) = (average absorbance of test sample-negative group absorbance) / (positive group absorbance-negative group absorbance) x 100

[0053] The test results are shown in Table 1:

[0054] Table 1

[0055]

[0056]

[0057] As can be seen from Table 1, the antibacterial performance of the chitosan dressing is improved with the increase of the injection amount of TiO2, and the biocompatibility of the dressing shows a trend of first increasing and then decreasing.

[0058] It should be noted that in order to ensure the comparability of each group of samples, the present application intentionally selects a high concentration of bacterial solution during antibacterial test, so as to ensure that each group of samples cannot achieve 100% antibacterial rate.

[0059] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method of preparing a medical surgical dressing, characterized by, The preparation method comprises the following steps: 1-3 g of chitosan powder is added into 50-80 mL of acetic acid solution with a mass concentration of 1.5-1.8 wt%, and stirred until completely dissolved to obtain a chitosan-acetic acid solution, and the solution is poured into a twelve-hole plate and pre-frozen at low temperature; after complete freezing, the solution is transferred into a vacuum freeze dryer for freeze-drying to obtain a sponge-like chitosan dressing intermediate product; the intermediate product is immersed in 1.5-1.8 M ammonia water to remove the residual acetic acid on the surface; after soaking for 2.5-3 h, the sponge-like chitosan dressing is taken out, repeatedly washed with deionized water for several times until the washing liquid is free of alkaline components, and then the water in the sponge-like chitosan dressing is squeezed out, and the sponge-like chitosan dressing is pre-frozen at low temperature again, and after complete freezing of the solution, the sponge-like chitosan dressing is subjected to secondary freeze-drying to obtain a sponge-like chitosan dressing; The chitosan dressing is placed in a sputtering film coating machine, a γ-type iron oxide / TiO2 composite target is used as a sputtering target material, and an inert gas is used as a working gas to uniformly sputter γ-type iron oxide / TiO2 on the surface of the chitosan dressing, and by adjusting the sputtering time, the mass of TiO2 is 1.2-2.1% of the total mass of the dressing, and the mass of γ-type iron oxide is 0.9% of the total mass of the dressing.

2. A process according to claim 1, wherein the process is carried out at a temperature of from 20 to 100°C. The pre-freezing temperature is -25℃.

3. A preparation method as described in claim 1, characterized in that, The concentration of the ammonia water is 1.5 M.

4. A preparation method as described in claim 1, characterized in that, The concentration of the acetic acid solution is 1.5 wt%.

5. A preparation method as described in claim 1, characterized in that, The inert gas is argon.

6. A preparation method as described in claim 1, characterized in that, The soaking time is 2.5 h.

7. A preparation method as described in claim 1, characterized in that, The sputtering is magnetic sputtering.

8. A medical surgical dressing, characterized by The medical surgical dressing is prepared by any one of the methods of claims 1-7.

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