Degradable wound dressing and preparation method thereof

Abstract

The present invention discloses a degradable wound dressing and a preparation method thereof. The degradable wound dressing is made from the following raw materials, calculated by weight: 70-80 parts starch; 10-20 parts chitosan derivative; 10-30 parts water; 1-10 parts plasticizer; 1-5 parts cross-linking agent; and 5-10 parts nano-titanium dioxide. By using starch as the main film-forming substance, adding chitosan derivatives to improve water solubility and thus increase degradation speed, and adding nano-titanium dioxide, which can generate hydroxyl radicals from water molecules when exposed to sunlight, further promoting starch oxidation and increasing degradation speed, and the nano-titanium dioxide generates active oxygen species under sunlight that can destroy bacterial structures and accelerate wound healing. Therefore, the degradable wound dressing has a fast degradation rate and good wound healing effect.

Description

Technical Field

[0001] The present invention belongs to the field of biopolymer medical materials, and more specifically, relates to a degradable wound dressing and a preparation method thereof. Background Art

[0002] Wound dressings are currently a commonly used medical product, primarily used for bandaging human wounds. Common wound dressing materials are made from synthetic polymers such as polyacrylamide and polyacrylonitrile. However, these synthetic materials are traditional petroleum-based and difficult to be degraded by microorganisms in the natural environment, posing a risk of environmental pollution during use. In recent years, research on starch-based materials has gained significant attention. Starch, as a natural polymer material, is abundant in nature and exhibits excellent film-forming properties, making it a promising green polymer material with significant application value.

[0003] Chitosan is a linear, high-molecular-weight polysaccharide compound, a deacetylated form of chitin. It carries a positive charge and is non-immunogenic. However, its insolubility in water significantly limits its applications, particularly in medical materials. Existing wound dressings made with chitosan, while possessing good antimicrobial properties, suffer from slow degradation, limiting their application. Therefore, there is a need for a new biodegradable wound dressing with faster degradation and improved healing properties. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a degradable wound dressing, which is green and environmentally friendly, degrades quickly, and has a good wound healing effect.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A degradable wound dressing is made from the following raw materials calculated in parts by weight:

[0007]

[0008] The chitosan derivative is one or more of an acylated chitosan derivative, a carboxylated chitosan derivative, an alkylated chitosan derivative or a quaternized chitosan derivative.

[0009] In the above scheme, starch is used as the main film-forming substance, and chitosan derivatives are added. The chitosan derivatives can increase their solubility in water through the introduced groups, thereby increasing the solubility of the wound dressing in water, thereby reducing the degree of polymerization of starch, and further increasing the degradation rate; in addition, nano-titanium dioxide is added to the system. When nano-titanium dioxide is irradiated with ultraviolet light, it will cause water molecules to produce hydroxyl free radicals, thereby promoting starch oxidation and accelerating the degradation rate. In addition, nano-titanium dioxide generates active oxygen species under sunlight that can destroy bacterial structure and accelerate wound healing. Chitosan derivatives have strong adhesion to cells. Nano-titanium dioxide and chitosan derivatives work together to make the prepared wound dressing degrade faster and have a better healing effect.

[0010] Furthermore, the acylated chitosan derivative is maleic anhydride acylated chitosan; the carboxylated chitosan derivative is N-ketoglutaric acid chitosan; the alkylated chitosan derivative is carboxymethyl chitosan and / or N,N-dilauryl chitosan; and the quaternized chitosan derivative is N,N,N-trimethyl chitosan.

[0011] Furthermore, the chitosan derivative is an alkylated chitosan derivative.

[0012] Chitosan derivatives can be prepared according to existing technologies. For example, the preparation method of maleic anhydride acylated chitosan is as follows:

[0013] Chitosan was dispersed in water, sodium carbonate was added, maleic anhydride was added after 0.5 h, the pH was adjusted to 10 after mixing for 6 h, and then the solution was obtained by centrifugation. Hydrochloric acid was added to the solution, and the pH was adjusted until a large amount of flocs were precipitated. The solution was centrifuged, and the precipitate was washed with acetone, vacuum dried, and allowed to stand overnight to obtain dry maleic anhydride acylated chitosan.

[0014] The preparation method of the N-ketoglutarate chitosan is as follows:

[0015] Chitosan was dissolved in an aqueous acetic acid solution, α-ketoglutaric acid was added, and the mixture was stirred at 37°C for 24 hours. Then, sodium borohydride was added and the reaction was continued at 37°C for 10 hours. The reaction was terminated with 95% ethanol to obtain a fibrous solid. After filtration, the solid was washed three times with ethanol and ether, respectively, and then dried naturally to obtain N-ketoglutaric acid chitosan.

[0016] The preparation method of the carboxymethyl chitosan is as follows:

[0017] Chitosan is dissolved in water, sodium hydroxide is added in batches for expansion, chloroacetic acid is added to react for 5 to 6 hours, hydrochloric acid is added to adjust to neutrality, and then filtered, washed and dried in sequence to obtain carboxymethyl chitosan.

[0018] The preparation method of the N,N-dilauryl chitosan is as follows:

[0019] Chitosan was dissolved in acetic acid, dodecanedial was added and stirred for reaction, then the pH was adjusted to 5, 10% sodium borohydride solution was added, stirred for 2-3 hours, the pH was adjusted to 7-9, and then filtered and dried to obtain N,N-dilauryl chitosan.

[0020] The preparation method of the N,N,N-trimethyl chitosan is as follows:

[0021] Chitosan, formaldehyde, formic acid, and water were mixed and reacted at 70°C for 118 hours, then concentrated, diluted with 1 mol / L sodium hydroxide to a pH of 12 (gel formation), and filtered to obtain a filter cake. The filter cake was washed with water, dissolved in a pH-4 hydrochloric acid solution, dialyzed against distilled water for 3 days, and freeze-dried to obtain a white solid. The white solid was dissolved in water, then adjusted to a pH of 12 with 1 mol / L sodium hydroxide (gel formation), washed with water and acetone, and then N-methylpyrrolidone and iodomethane were added. The reaction was stirred at 40°C for 96 hours, followed by cooling. After cooling, the product was precipitated with a 1:1 volume ratio of anhydrous ethanol / anhydrous ether mixture. The filter cake was filtered, washed with anhydrous ether, dried overnight, and then dissolved in a sodium chloride solution with stirring at room temperature for 18 hours. The mixture was then dialyzed against water for 3 days and freeze-dried to obtain N,N,N-trimethylchitosan.

[0022] Furthermore, the starch is one or more of potato starch, corn starch, and glutinous rice starch.

[0023] Furthermore, the plasticizer is one or more of glycerol, diglycerol, sorbitol, citric acid, and polyethylene glycol.

[0024] Furthermore, the cross-linking agent is one or more of sodium hydroxide, acetic acid, calcium hydroxide or methanol.

[0025] The preparation method of the degradable wound dressing comprises the following steps:

[0026] S1. The water, chitosan derivative, nano-titanium dioxide, plasticizer and crosslinking agent were stirred and mixed in proportion and then ultrasonically treated to obtain a first mixture;

[0027] S2. The first mixture in step S1 is added to the starch, stirred and mixed, and sealed and balanced to obtain a second mixture;

[0028] S3. Take 1 to 5 g of the second mixture in step S2, subject it to hot pressing and cooling to obtain a degradable wound dressing.

[0029] Furthermore, in step S1, the rotation speed of the stirring and mixing is 500 to 1000 r / min.

[0030] Furthermore, in step S1., the stirring and mixing temperature is 30-40°C.

[0031] Furthermore, in step S1., the stirring and mixing time is 15 to 30 minutes.

[0032] Furthermore, in step S1., the ultrasonic treatment time is 10 to 30 minutes.

[0033] Furthermore, in step S1., the power of the ultrasonic treatment is 450 to 630W.

[0034] Furthermore, in step S2, the rotation speed of the stirring and mixing is 500 to 1000 r / min.

[0035] Furthermore, in step S2, the temperature of the stirring and mixing is 25-28°C.

[0036] Furthermore, in step S2, the stirring and mixing time is 0.5 to 2.5 hours.

[0037] Furthermore, in step S2, the sealing balance time is 12 to 72 hours.

[0038] Furthermore, in step S3, the temperature of the hot pressing treatment is 120-140°C.

[0039] Furthermore, in step S3, the pressure of the hot pressing treatment is 1 to 5 MPa.

[0040] Furthermore, in step S3, the hot pressing treatment time is 1 to 10 minutes.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides a degradable wound dressing. The degradable wound dressing uses starch as a main film-forming substance, and is added with chitosan derivatives and nano-titanium dioxide. The chitosan derivatives can effectively improve its water solubility and thus accelerate degradation. The nano-titanium dioxide oxidizes water molecules into hydroxyl radicals, promotes the oxidation of starch, and increases the degradation rate. The nano-titanium dioxide and the chitosan derivatives act synergistically, so that the prepared degradable wound dressing has a faster degradation rate, which is not less than 0.0140 g / h, and the hemostasis time does not exceed 4.2 minutes, and the wound healing time does not exceed 4 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the preparation of the degradable wound dressing of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further elaborated below in conjunction with specific examples, which are only used to explain the present invention and are not intended to limit the scope of the invention. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0045] Acylated chitosan derivatives:

[0046] Maleic anhydride acylated chitosan: 3g of chitosan was uniformly dispersed in 300mL of water under mechanical stirring. 1g of sodium carbonate was then added. 0.5h later, 360g of maleic anhydride was added. After mixing for 6h, stirring was stopped and 2.0mol / L potassium hydroxide was added. The pH was adjusted to 10. Unreacted chitosan was separated by high-speed centrifugation to obtain a solution. Hydrochloric acid was added to the solution and the pH was adjusted until a large amount of flocculent material precipitated. The solution was centrifuged and the precipitate was washed with acetone, dried under vacuum, and allowed to stand overnight to obtain dry maleic anhydride acylated chitosan.

[0047] Carboxylated chitosan derivatives:

[0048] N-ketoglutaric acid chitosan: Dissolve 2g of chitosan in 60mL of 1% aqueous acetic acid solution, add 3.20g of α-ketoglutaric acid, stir at 37℃ for 24h, then add 0.80g of sodium borohydride, and continue to react at 37℃ for 10h. Terminate the reaction with 95% ethanol to obtain a fibrous solid. After filtering, wash with ethanol and ether three times respectively, and dry naturally to obtain N-ketoglutaric acid chitosan.

[0049] Alkylated chitosan derivatives:

[0050] N,N-dilauryl chitosan: Dissolve 2 g of chitosan in 20 mL of 1% acetic acid solution, slowly add 0.55 mL of dodecanedal and stir to react, then adjust the pH to 5, add 0.825 mL of 10% sodium borohydride solution, stir for 2 h, adjust the pH to 7-9, and then filter through anhydrous ethanol and vacuum dry to obtain N,N-dilauryl chitosan.

[0051] Carboxymethyl chitosan: Dissolve 2 g of chitosan in 20 mL of water, add 8.5 g of sodium hydroxide in portions and swell for 2 h, add 10 g of chloroacetic acid in portions and react for 6 h, add hydrochloric acid to adjust the pH to neutral, filter and obtain a filter cake, wash with 70% by volume methanol, 95% by volume ethanol and anhydrous ethanol in sequence, and dry the product at 60°C to obtain carboxymethyl chitosan.

[0052] Quaternized chitosan derivatives:

[0053] N,N,N-trimethylchitosan: 2 g of chitosan, 8 mL of formaldehyde, 6 mL of formic acid, and 36 mL of distilled water were placed in a 100 mL round-bottom flask and stirred at 70°C for 118 h. The mixture was then concentrated, diluted with 1 mol / L sodium hydroxide to a pH of 12 (gel formation), and filtered. The filter cake was washed with distilled water, dissolved in 80 mL of hydrochloric acid (pH 4), dialyzed against water for 3 d, and freeze-dried to obtain a white solid. 1 g of the white solid was dissolved in 160 mL of water, then adjusted to a pH of 12 (gel formation) with 1 mol / L sodium hydroxide. The solid was washed sequentially with water and acetone, then transferred to a 1 L round-bottom flask. 200 mL of N-methylpyrrolidone and 8 mL of iodomethane were added and stirred at 40°C for 96 h. After cooling, the product was precipitated with a 1:1 (volume ratio) mixture of anhydrous ethanol and anhydrous ether. The filter cake was filtered, washed with anhydrous ether, dried overnight, and then dissolved in 200 mL of 10% sodium chloride solution and stirred at room temperature for 18 h. The mixture was then dialyzed with water for 3 days and freeze-dried to obtain N, N, N-trimethyl chitosan.

[0054] The schematic diagram of the preparation of the degradable wound dressing of the present invention is as follows Figure 1 shown.

[0055] Example 1

[0056] A degradable wound dressing is made from the following raw materials calculated in parts by weight: 70 parts by weight of potato starch, 10 parts by weight of N,N-dilauryl chitosan, 15 parts by weight of water, 5 parts by weight of glycerol, 1 part by weight of acetic acid, and 5 parts by weight of nano-titanium dioxide.

[0057] A method for preparing a degradable wound dressing comprises the following steps:

[0058] S1. The above parts by weight of water, N, N-didodecyl chitosan, nano-titanium dioxide, glycerol and acetic acid were stirred in a water bath at 35 ° C using a magnetic stirrer at a speed of 600 r / min for 15 min, and then ultrasonically treated for 15 min to obtain a first mixture;

[0059] S2. The first mixture in step S1 is added to the above parts by weight of potato starch, and the mixture is stirred and mixed, sealed and balanced to obtain a second mixture; the stirring and mixing speed is 800 r / min, the stirring and mixing time is 1 h, and the sealing and balancing time is 24 h;

[0060] S3. Take 2 g of the second mixture in step S2. and subject it to autoclaving and cooling to obtain a degradable wound dressing; the autoclaving temperature is 120°C, the autoclaving pressure is 4 MPa, and the autoclaving time is 6 min.

[0061] Example 2

[0062] A degradable wound dressing is made from the following raw materials calculated in parts by weight: 75 parts by weight of glutinous rice starch, 15 parts by weight of N,N-dilauryl chitosan, 25 parts by weight of water, 5 parts by weight of citric acid, 1 part by weight of acetic acid, and 5 parts by weight of nano-titanium dioxide.

[0063] A method for preparing a degradable wound dressing comprises the following steps:

[0064] S1. The above parts by weight of water, N, N-didodecyl chitosan, nano-titanium dioxide, glycerol and acetic acid were stirred in a water bath at 35 ° C using a magnetic stirrer at a speed of 500r / min for 20min, followed by ultrasonic treatment for 20min to obtain a first mixture;

[0065] S2. The first mixture in step S1 is added to the above parts by weight of glutinous rice starch, followed by stirring and mixing, sealing and balancing to obtain a second mixture; the stirring and mixing speed is 700 r / min, the stirring and mixing time is 1.5h, and the sealing and balancing time is 24h;

[0066] S3. Take 3 g of the second mixture in step S2. and heat-press and cool to obtain a degradable wound dressing; the heat-pressing temperature is 140°C, the heat-pressing pressure is 2 MPa, and the heat-pressing time is 9 min.

[0067] Example 3

[0068] A degradable wound dressing is made from the following raw materials calculated in parts by weight: 80 parts by weight of corn starch, 15 parts by weight of N,N-dilauryl chitosan, 20 parts by weight of water, 5 parts by weight of sorbitol, 1 part by weight of calcium oxide, and 5 parts by weight of nano-titanium dioxide.

[0069] A method for preparing a degradable wound dressing comprises the following steps:

[0070] S1. The above parts by weight of water, N, N-didodecyl chitosan, nano-titanium dioxide, glycerol and acetic acid were stirred in a water bath at 35 ° C using a magnetic stirrer at a speed of 700 r / min for 15 min, followed by ultrasonic treatment for 25 min to obtain a first mixture;

[0071] S2. The first mixture in step S1 is added to the above parts by weight of corn starch, followed by stirring and mixing, sealing and balancing to obtain a second mixture; the stirring and mixing speed is 900 r / min, the stirring and mixing time is 2h, and the sealing and balancing time is 36h;

[0072] S3. Take 4 g of the second mixture in step S2. and heat-press and cool to obtain a degradable wound dressing; the heat-pressing temperature is 140°C, the heat-pressing pressure is 4 MPa, and the heat-pressing time is 7 min.

[0073] Example 4

[0074] A degradable wound dressing is prepared from the following raw materials calculated in parts by weight: 70 parts by weight of potato starch, 10 parts by weight of carboxymethyl chitosan, 25 parts by weight of water, 5 parts by weight of diglycerol, 1 part by weight of acetic acid, and 10 parts by weight of nano-titanium dioxide.

[0075] A method for preparing a degradable wound dressing comprises the following steps:

[0076] S1. The above parts by weight of water, carboxymethyl chitosan, nano-titanium dioxide, glycerol and acetic acid were mixed in a water bath at 35 ° C using a magnetic stirrer at a speed of 800r / min for 20min, followed by ultrasonic treatment for 30min to obtain a first mixture;

[0077] S2. The first mixture in step S1 is added to the above parts by weight of potato starch, and stirred and mixed, sealed and balanced to obtain a second mixture; the stirring and mixing speed is 800 r / min, the stirring and mixing time is 1.5h, and the sealing and balancing time is 36h;

[0078] S3. Take 3 g of the second mixture in step S2. and heat press and cool to obtain a degradable wound dressing; the heat press temperature is 120°C, the heat press pressure is 3 MPa, and the heat press time is 8 min.

[0079] Example 5

[0080] A degradable wound dressing is made from the following raw materials calculated in parts by weight: 80 parts by weight of corn starch, 15 parts by weight of N,N-dilauryl chitosan, 20 parts by weight of water, 5 parts by weight of polyethylene glycol, 1 part by weight of acetic acid, and 10 parts by weight of nano-titanium dioxide.

[0081] A method for preparing a degradable wound dressing comprises the following steps:

[0082] S1. The above parts by weight of water, N, N-didodecyl chitosan, nano-titanium dioxide, glycerol and acetic acid were stirred in a water bath at 35 ° C using a magnetic stirrer at a speed of 900r / min for 30min, followed by ultrasonic treatment for 20min to obtain a first mixture;

[0083] S2. The first mixture in step S1 is added to the above parts by weight of potato starch, and stirred and mixed, sealed and balanced to obtain a second mixture; the stirring and mixing speed is 1000 r / min, the stirring and mixing time is 2.5h, and the sealing and balancing time is 48h;

[0084] S3. Take 5 g of the second mixture in step S2. and subject it to autoclaving and cooling to obtain a degradable wound dressing; the autoclaving temperature is 140°C, the autoclaving pressure is 5 MPa, and the autoclaving time is 3 min.

[0085] Example 6

[0086] The steps and parameters are the same as those in Example 1, except that maleic anhydride acylated chitosan is used instead of N,N-dilaurylated chitosan.

[0087] Example 7

[0088] The steps and parameters are the same as those in Example 1, except that N-ketoglutaric acid chitosan is used instead of N,N-dilauryl chitosan.

[0089] Example 8

[0090] The steps and parameters are the same as those in Example 1, except that N,N,N-trimethyl chitosan is used instead of N,N-dilauryl chitosan.

[0091] Comparative Example 1

[0092] A degradable wound dressing is prepared from the following raw materials calculated in parts by weight: 70 parts of potato starch, 15 parts by weight of chitosan, 15 parts of water, 5 parts of glycerol, 1 part of acetic acid, and 5 parts of nano-titanium dioxide.

[0093] A method for preparing a degradable wound dressing comprises the following steps:

[0094] S1. The above parts by weight of water, nano-titanium dioxide, glycerol and acetic acid were mixed in a water bath at 35 ° C using a magnetic stirrer at a speed of 600 r / min for 15 min, and then ultrasonically treated for 15 min to obtain a first mixture;

[0095] S2. The first mixture in step S1 is added to the above parts by weight of potato starch, and the mixture is stirred and mixed, sealed and balanced to obtain a second mixture; the stirring and mixing speed is 800 r / min, the stirring and mixing time is 1 h, and the sealing and balancing time is 24 h;

[0096] S3. Take 2 g of the second mixture in step S2. and subject it to autoclaving and cooling to obtain a degradable wound dressing; the autoclaving temperature is 120°C, the autoclaving pressure is 4 MPa, and the autoclaving time is 6 min.

[0097] Comparative Example 2

[0098] A degradable wound dressing is prepared from the following raw materials calculated in parts by weight: 70 parts by weight of potato starch, 10 parts by weight of N,N-dilauryl chitosan, 15 parts by weight of water, 5 parts by weight of glycerol, and 1 part by weight of acetic acid.

[0099] A method for preparing a degradable wound dressing comprises the following steps:

[0100] S1. The above parts by weight of water, N, N-didodecyl chitosan, glycerol and acetic acid were stirred in a water bath at 35 ° C using a magnetic stirrer at a speed of 600 r / min for 15 min, and then ultrasonically treated for 15 min to obtain a first mixture;

[0101] S2. The first mixture in step S1 is added to the above parts by weight of potato starch, and the mixture is stirred and mixed, sealed and balanced to obtain a second mixture; the stirring and mixing speed is 800 r / min, the stirring and mixing time is 1 h, and the sealing and balancing time is 24 h;

[0102] S3. Take 2 g of the second mixture in step S2. and subject it to autoclaving and cooling to obtain a degradable wound dressing; the autoclaving temperature is 120°C, the autoclaving pressure is 4 MPa, and the autoclaving time is 6 min.

[0103] Performance Testing

[0104] The performance of the degradable wound dressings of Examples 1 to 8 and Comparative Examples 1 to 2 was tested by the following method.

[0105] (1) Degradation rate: Examples 1 to 8 and Comparative Examples 1 to 2 were subjected to a soil burial degradation performance test. Each sample was weighed before burial, buried for 12 hours after weighing, and weighed again after 12 hours.

[0106] Calculation of results:

[0107]

[0108] (2) Hemostatic performance test: 50 rats, weighing 180 g ± 20 g, were used as test subjects and divided into 10 groups, with five rats in each group. The rats were anesthetized with an intraperitoneal injection of 2% sodium pentobarbital at a concentration of 45 mg / kg body weight, and then fixed. The hair of the back was shaved off and disinfected in an area of ​​2 cm * 2 cm. A wound 1 cm long and 2 mm deep was made at the hair-cut area using a sterilized blade. 2 cm * 2 cm of the degradable wound dressings of Examples 1 to 8 and Comparative Examples 1 to 2 were applied to the wounds, and the hemostasis time was recorded.

[0109] (3) Wound healing test: The wounds of the rats in each group after surgery in (2) were re-applied with wound dressings of the same size and bandaged with sterile gauze. The rats were fed normally and the wound healing was observed daily. The time of wound healing was recorded. The test results are shown in Table 1.

[0110] Table 1 Test results of Examples 1 to 8 and Comparative Examples 1 to 2

[0111]

[0112] As can be seen from Table 1, the degradation rate of the degradable wound dressing of the present invention is not less than 0.0140 g / h, the hemostasis time is not more than 4.2 minutes, and the wound healing time is not more than 4 days.

[0113] As can be seen from Example 1 and Examples 6 to 8, when the chitosan derivative is an alkylated chitosan, the comprehensive performance of the degradable wound dressing prepared is better. The degradation rate of the degradable wound dressing prepared using the alkylated chitosan derivative is 0.0151 g / h, the hemostasis time is 3.5 minutes, and the wound healing time is 3 days. The hemostasis time is reduced by at least 10.26%, and the wound healing time is reduced by at least 9.38%.

[0114] As can be seen from Comparative Example 1, the degradation rate of the degradable wound dressing prepared by replacing the chitosan derivative with chitosan is significantly lower than that of the degradable wound dressing using the chitosan derivative, which is only 0.0114 g / h, a decrease of 24.5%; and the hemostasis time and wound healing time of the degradable wound dressing are significantly prolonged.

[0115] It can be seen from Comparative Example 2 that when nano-titanium dioxide is not added, the degradation rate of the prepared degradable wound dressing is significantly reduced to only 0.0057 g / h, the hemostasis time is 5.2 minutes, and the wound healing time is 6.5 days.

[0116] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A degradable wound dressing, characterized in that: Made from the following raw materials calculated by weight: 70-80 parts of starch; 10-20 parts of chitosan derivative; 10-30 parts water; 1 to 10 parts of plasticizer; 1 to 5 parts of a cross-linking agent; 5-10 parts of nano titanium dioxide; The chitosan derivative is an alkylated chitosan derivative; the starch is one or more of potato starch, corn starch, and glutinous rice starch; The preparation method of the degradable wound dressing comprises the following steps: S1. The water, chitosan derivative, nano-titanium dioxide, plasticizer and crosslinking agent were stirred and mixed in proportion and then ultrasonically treated to obtain a first mixture; S2. The first mixture in step S1 is added to the starch, stirred and mixed, and sealed and balanced to obtain a second mixture; S3. Take 1 to 5 g of the second mixture in step S2, subject it to hot pressing and cooling to obtain a degradable wound dressing.

2. The degradable wound dressing according to claim 1, characterized in that: The plasticizer is one or more of glycerol, diglycerol, sorbitol, citric acid, and polyethylene glycol.

3. The degradable wound dressing according to claim 1, characterized in that: The cross-linking agent is one or more of sodium hydroxide, acetic acid, calcium hydroxide and methanol.

4. The method for preparing the degradable wound dressing according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. The water, chitosan derivative, nano-titanium dioxide, plasticizer and crosslinking agent were stirred and mixed in proportion and then ultrasonically treated to obtain a first mixture; S2. The first mixture in step S1 is added to the starch, stirred and mixed, and sealed and balanced to obtain a second mixture; S3. Take 1 to 5 g of the second mixture in step S2, subject it to hot pressing and cooling to obtain a degradable wound dressing.

5. The preparation method according to claim 4, characterized in that: In step S2, the sealing balance time is 12 to 72 hours.

6. The preparation method according to claim 4, characterized in that: In step S3, the temperature of the hot pressing treatment is 120-140°C.

7. The preparation method according to claim 4, characterized in that: In step S3, the pressure of the hot pressing treatment is 1 to 5 MPa.

8. The preparation method according to claim 4, characterized in that: In step S3, the heat pressing treatment is performed for 1 to 10 minutes.

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