Preparation method and application of an antibacterial hydrogel dressing with multiple adhesion properties

Abstract

The invention discloses a preparation method and application of a multifunctional novel antibacterial hydrogel wound dressing with excellent adhesion performance. The antibacterial hydrogel dressing uses chitosan as a carrier, grafts caffeic acid onto the chitosan chain to improve its antibacterial and wet adhesion capabilities, and simultaneously loads aloin through an impregnation method to provide better antibacterial and antioxidant functions. The prepared multifunctional hydrogel dressing (CS / CA / Alo) should be able to promote the recovery of open wounds occurring on the skin and mucous membranes with its wet adhesion performance, antibacterial and antioxidant capabilities. Compared with existing conventional skin and mucous membrane wet dressings, this multifunctional hydrogel film can be synthesized by a more environmentally friendly and economical method, and has stronger wet adhesion ability, ductility, antibacterial and antioxidant capabilities, thereby promoting wound healing.

Description

Technical Field

[0001] The present invention relates to the technical field of medical dressings, and more particularly to a preparation method and application of an antibacterial hydrogel dressing having multiple adhesion properties. Background Art

[0002] Skin and mucous membranes are the most important barriers of the human body. Due to trauma, surgery, etc., the integrity of the skin and mucous membranes is often damaged, resulting in pain, bleeding, and even disability and death. Wound healing is a dynamic, multi-factor biological process, including hemostasis, inflammatory response, cell proliferation, angiogenesis, and tissue regeneration. Open skin / mucous membrane wounds usually take 8 - 12 weeks to heal. However, this orderly process may be disturbed by adverse factors, such as bacterial infection, low immunity, excessive activity, and elevated local skin / mucous membrane temperature. To avoid the occurrence of these complications, we often need to cover a protective dressing, such as gauze, at the wound site. Although there are various wound dressings available now, they usually show disadvantages such as poor mechanical matching with tissues and weak adhesiveness. When applied to joints with large mobility, such as the wrist joint and elbow joint, it is difficult to firmly cover these dressings on the wound, which cannot provide good protection and promote wound healing. In addition, due to the presence of interfacial water, the adhesion of conventional dressings to wet tissues is also a great challenge.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of an antibacterial hydrogel dressing having multiple adhesion properties. This hydrogel dressing is not restricted by local activities, can provide firm adhesion, is particularly applicable to joints with large mobility, can prevent infection and promote wound healing without forming scars, and can be applied to the skin, wet tissues, and even internal organs.

[0005] The present invention is implemented as follows:

[0006] In a first aspect, the present invention provides a preparation method of an antibacterial hydrogel wound dressing having multiple adhesion properties, which includes reacting chitosan with caffeic acid to form a CS / CA polymer; then curing the CS / CA polymer to form a CS / CA hydrogel, and then immersing the CS / CA hydrogel in an aloin solution, and freeze-drying to obtain the antibacterial hydrogel wound dressing.

[0007] In some embodiments, the step of forming the CS / CA polymer includes adjusting the pH of the mixed solution after mixing the chitosan solution and the solution containing caffeic acid, dialysis, and freeze-drying.

[0008] In some embodiments, the pH of the mixed solution is adjusted to 4.5 - 5.0.

[0009] In some embodiments, dialysis includes first dialyzing the mixed solution in a dialysis solution containing sodium chloride for the first time, and then dialyzing it in an ultralight water dialysate for the second time.

[0010] In some embodiments, in the first dialysis, the pH of the dialysis solution is 4 - 4.5, the concentration of sodium chloride is 10 mmol, the dialysis time is 48 h; the time for the second dialysis is 4 h.

[0011] In some embodiments, the temperature of freeze-drying is -20 °C and the time is 36 - 48 h.

[0012] In some embodiments, the molecular weight of chitosan in the chitosan solution is: 50,000 - 190,000, and the degree of deacetylation is 75 - 85; the pH of the chitosan solution is 5 - 5.5.

[0013] In some embodiments, the mass ratio of chitosan to caffeic acid is 1:1.18.

[0014] In some embodiments, the solute in the solution containing caffeic acid further includes carbodiimide and N-hydroxysulfosuccinimide, and the solvent is ethanol.

[0015] In some embodiments, the mass ratio of caffeic acid, carbodiimide, and N-hydroxysulfosuccinimide contained in every 20 ml of ethanol in the solution containing caffeic acid is: 1.18:1.25:0.748.

[0016] In some embodiments, the concentration of aloin in the aloin solution is 4 - 8 mg / L.

[0017] In some embodiments, the soaking time of the CS / CA hydrogel in the aloin solution is 10 - 12 h.

[0018] In some embodiments, the steps of preparing the CS / CA hydrogel include: dissolving the CS / CA polymer, n-hydroxysuccinimide acrylate, and α-ketoglutaric acid in an acrylic acid solution, mixing evenly, curing, and freeze-drying to obtain the CS / CA hydrogel.

[0019] In some embodiments, in every 1 mL of acrylic acid solution, the mass ratio of the CS / CA polymer, n-hydroxysuccinimide acrylate, and α-ketoglutaric acid is 20:10:2.

[0020] In some embodiments, the volume concentration of the acrylic acid solution is 30%.

[0021] In some embodiments, the curing time is 20 - 30 min.

[0022] In some embodiments, the temperature of lyophilization is -20°C and the time is 36 - 48 h.

[0023] In a second aspect, the present invention also provides an antibacterial hydrogel dressing prepared by the preparation method of the above antibacterial hydrogel dressing.

[0024] In a third aspect, the present invention also provides the application of the above antibacterial hydrogel dressing in wound treatment. The wounds in the present invention include wounds on the skin, wet tissues, and internal organs.

[0025] The present invention has the following beneficial effects:

[0026] The present invention uses chitosan as a carrier, grafts caffeic acid onto the chitosan chain to improve its antibacterial and wet adhesion capabilities, and simultaneously loads aloin by the impregnation method to provide better antibacterial and antioxidant functions. The prepared multifunctional hydrogel dressing (CS / CA / Alo) should be able to promote the recovery of open wounds occurring on the skin and mucous membranes with its wet adhesion performance, antibacterial, and antioxidant capabilities. Compared with existing conventional skin and mucous membrane wet dressings, this multifunctional hydrogel film can be synthesized by a more environmentally friendly and economical method, and has stronger wet adhesion ability, ductility, antibacterial, and antioxidant capabilities, thus promoting wound healing. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0028] Figure 1 For the results of the bonding mechanics test in the experimental examples;

[0029] Figure 2 For the results of the bonding tests carried out for different parts and different bending degrees in the experimental examples;

[0030] Figure 3 For the results of the bonding tests carried out for different materials in the experimental examples;

[0031] Figure 4 For the bacteriostatic activity test chart against Staphylococcus aureus in the experimental examples;

[0032] Figure 5 For the bacteriostatic activity data chart against Staphylococcus aureus in the experimental examples;

[0033] Figure 6 For the bacteriostatic activity test chart against Escherichia coli in the experimental examples;

[0034] Figure 7 It is the antibacterial activity data graph against Escherichia coli in the experimental examples;

[0035] Figure 8 It is the ROS measurement images of L929 and HUVEC cells in the experimental examples;

[0036] Figure 9 It is the fluorescence quantitative statistics of ROS measurement of L929 and HUVEC cells in the experimental examples. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0038] Chitosan (CS) is the deacetylated product of chitin and is a naturally occurring polysaccharide material. Chitosan-based dressings exhibit good biocompatibility and biodegradability during the wound healing process. At the same time, they also have the functions of antibacterial and anti-inflammatory, hemostasis and pain relief, promoting wound healing, nourishing and repairing mucous membranes, and immunomodulatory activity.

[0039] Caffeic acid (CA), also known as 3,4-dihydroxycinnamic acid, is a polyhydroxy cinnamic acid derivative and belongs to one of the hydroxycinnamic acid esters and phenylpropanoid metabolites in plant tissues. It has various pharmacological effects such as anti-inflammatory, antibacterial, antiviral, increasing white blood cells and platelets.

[0040] Aloin (Alo) is a natural organic compound, also known as aloin, aloe-emodin glycoside, aloin. Research shows that aloin has the effects of enhancing immune function, anti-tumor, detoxifying and laxative, antibacterial, anti-gastric injury and liver protection, and skin protection.

[0041] On the one hand, the present invention increases the adhesion ability by forming hydrogen bonds between caffeic acid and tissues; on the other hand, impregnating the prepared hydrogel in the aloin solution can not only improve the antibacterial and antioxidant abilities of the dressing, but also, because aloin can also form partial hydrogen bonds, it synergistically improves the wet adhesion ability of the dressing with caffeic acid.

[0042] Specifically, the preparation method of an antibacterial hydrogel dressing with various bonding properties provided by the present invention is as follows:

[0043] S1. Synthesis of CS / CA polymer

[0044] (1) Dissolve 1 g of chitosan (CS) in distilled water under vigorous stirring to obtain a uniform solution.

[0045] (2) Add NaOH to the solution in (1) to adjust the pH to 5.5.

[0046] (3) Completely dissolve 1.18 g of caffeic acid (CA), 1.25 g of carbodiimide (EDC), and 0.748 g of N-hydroxysuccinimide (NHS) in 20 ml of ethanol. Among them, EDC is a dehydrating agent, mainly used to activate carboxyl groups and promote the formation of amides and esters; NHS is a condensing agent and can form a stable active ester intermediate.

[0047] (4) Add the mixture in (3) to the solution in (2), then adjust the pH to 5.0 and stir overnight.

[0048] (5) Dialyze the solution obtained in (4) under the condition of pH 4. The dialysis bag contains 10 mmol of sodium chloride, dialyze for 2 days, and then dialyze with deionized water (DDW) for 4 hours.

[0049] (6) Freeze the solution obtained in (5) in a -20 °C refrigerator overnight and lyophilize for 48 hours.

[0050] Synthesis of CS / CA / Alo Hydrogel

[0051] (1) Dissolve 400 mg of CS / CA polymer, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly. Among them, acrylic acid is a solvent and cross-linking agent, which couples multiple molecules respectively, so that these molecules are linked together; AAC-NHS is a water absorbent to remove water at the bonding interface; α-ketoglutaric acid is a photoinitiator.

[0052] (2) Pour the mixture in (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0053] (3) Freeze the hydrogel in (2) in a -20 °C refrigerator and lyophilize for 48 hours to obtain a dry CS / CA hydrogel.

[0054] (4) Add aloin (Alo) to deionized water (DDW) to prepare a solution.

[0055] (5) Immerse the hydrogel in (3) into the solution in (4) for 12 hours.

[0056] (6) Place the hydrogel in (5) in a -20 °C refrigerator and lyophilize for 48 hours.

[0057] The features and properties of the present invention will be further described in detail below in conjunction with the embodiments.

[0058] The molecular weight of chitosan used in the examples was: 100,000, and the degree of deacetylation was 80. All reagents were purchased from Macklin Reagents.

[0059] Example 1

[0060] The preparation method of an antibacterial hydrogel dressing with various adhesive properties provided in this example is as follows:

[0061] S1. Synthesis of CS / CA polymer

[0062] (1) Dissolve 1 g of chitosan (CS) in distilled water under vigorous stirring to obtain a homogeneous solution.

[0063] (2) Add NaOH to the solution in (1) to adjust the pH to 5.5.

[0064] (3) Completely dissolve 1.18 g of caffeic acid (CA), 1.25 g of carbodiimide (EDC), and 0.748 g of N-hydroxysulfosuccinimide (NHS) in 20 ml of ethanol.

[0065] (4) Add the mixture in (3) to the solution in (2), then adjust the pH to 5.0 and stir overnight.

[0066] (5) Dialyze the solution obtained in (4) under the condition of pH 4. The dialysis bag contains 10 mmol of sodium chloride. Dialyze for 2 days, and then dialyze with ultrapure water (DDW) for 4 hours.

[0067] (6) Freeze the solution obtained in (5) in a -20 °C refrigerator overnight and lyophilize for 48 hours.

[0068] S2. Synthesis of CS / CA / Alo hydrogel

[0069] (1) Dissolve 400 mg of CS / CA polymer, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0070] (2) Pour the mixture in (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0071] (3) Freeze and lyophilize the hydrogel in (2) in a -20 °C refrigerator for 48 hours to obtain a dry CS / CA hydrogel.

[0072] (4) Add aloin (Alo) to ultrapure water (DDW) to make a 2 mg / mL aloin solution.

[0073] (5) Immerse the hydrogel in (4) the solution for 12 hours.

[0074] (6) Place the hydrogel in (5) in a -20 °C refrigerator and freeze-dry for 48 hours.

[0075] Example 2

[0076] The present example provides a method for preparing an antibacterial hydrogel dressing with various adhesion properties as follows:

[0077] S1. Synthesis of CS / CA polymer

[0078] (1) Dissolve 1 g of chitosan (CS) in distilled water under vigorous stirring to obtain a uniform solution.

[0079] (2) Add NaOH to the solution in (1) to adjust the pH to 5.5.

[0080] (3) Completely dissolve 1.18 g of caffeic acid (CA), 1.25 g of carbodiimide (EDC), and 0.748 g of N-hydroxysuccinimide (NHS) in 20 ml of ethanol.

[0081] (4) Add the mixture in (3) to the solution in (2), then adjust the pH to 5.0 and stir overnight.

[0082] (5) Dialyze the solution obtained in (4) under the condition of pH 4. The dialysis bag contains 10 mmol of sodium chloride, dialyze for 2 days, and then dialyze with ultrapure water (DDW) for 4 hours.

[0083] (6) Freeze the solution obtained in (5) overnight in a -20 °C refrigerator and freeze-dry for 48 hours.

[0084] S2. Synthesis of CS / CA / Alo hydrogel

[0085] (1) Dissolve 400 mg of CS / CA polymer, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0086] (2) Pour the mixture in (1) into a polytetrafluoroethylene mold and cure with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0087] (3) Freeze and freeze-dry the hydrogel in (2) in a -20 °C refrigerator for 48 hours to obtain a dry CS / CA hydrogel.

[0088] (4) Add aloin (Alo) to ultrapure water (DDW) to make an aloin solution of 4 mg / mL.

[0089] (5) Immerse the hydrogel in (4) the solution for 12 hours.

[0090] (6) Place the hydrogel in (5) in a -20 °C refrigerator and freeze-dry for 48 hours.

[0091] Example 3

[0092] This example provides a preparation method of an antibacterial hydrogel dressing with various adhesion properties as follows:

[0093] S1. Synthesis of CS / CA polymer

[0094] (1) Dissolve 1 g of chitosan (CS) in distilled water under vigorous stirring to obtain a homogeneous solution.

[0095] (2) Add NaOH to the solution in (1) to adjust the pH to 5.5.

[0096] (3) Completely dissolve 1.18 g of caffeic acid (CA), 1.25 g of carbodiimide (EDC), and 0.748 g of N-hydroxysuccinimide (NHS) in 20 ml of ethanol.

[0097] (4) Add the mixture in (3) to the solution in (2), then adjust the pH to 5.0 and stir overnight.

[0098] (5) Dialyze the solution obtained in (4) under the condition of pH 4. The dialysis bag contains 10 mmol of sodium chloride, dialyze for 2 days, and then dialyze with ultrapure water (DDW) for 4 hours.

[0099] (6) Freeze the solution obtained in (5) in a -20 °C refrigerator overnight and freeze-dry for 48 hours.

[0100] S2. Synthesis of CS / CA / Alo hydrogel

[0101] (1) Dissolve 400 mg of CS / CA polymer, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0102] (2) Pour the mixture in (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0103] (3) Freeze and freeze-dry the hydrogel in (2) in a -20 °C refrigerator for 48 hours to obtain a dry CS / CA hydrogel.

[0104] (4) Add aloin (Alo) to deionized water (DDW) to prepare an aloin solution with a concentration of 6 mg / mL.

[0105] (5) Immerse the hydrogel prepared in (3) into the solution prepared in (4) for 12 hours.

[0106] (6) Place the hydrogel obtained in (5) in a -20 °C refrigerator and freeze-dry it for 48 hours.

[0107] Example 4

[0108] This example provides a method for preparing an antibacterial hydrogel dressing with multiple adhesive properties as follows:

[0109] S1. Synthesis of CS / CA polymer

[0110] (1) Dissolve 1 g of chitosan (CS) in distilled water under vigorous stirring to obtain a homogeneous solution.

[0111] (2) Add NaOH to the solution obtained in (1) to adjust the pH to 5.5.

[0112] (3) Completely dissolve 1.18 g of caffeic acid (CA), 1.25 g of carbodiimide (EDC) and 0.748 g of N-hydroxysuccinimide (NHS) in 20 ml of ethanol.

[0113] (4) Add the mixture obtained in (3) to the solution obtained in (2), then adjust the pH to 5.0 and stir overnight.

[0114] (5) Dialyze the solution obtained in (4) under the condition of pH = 4. The dialysis bag contains 10 mmol of sodium chloride. Dialyze for 2 days, and then dialyze with deionized water (DDW) for 4 hours.

[0115] (6) Freeze the solution obtained in (5) in a -20 °C refrigerator overnight and then freeze-dry it for 48 hours.

[0116] S2. Synthesis of CS / CA / Alo hydrogel

[0117] (1) Dissolve 400 mg of CS / CA polymer, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS) and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0118] (2) Pour the mixture obtained in (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0119] (3) Freeze and then freeze-dry the hydrogel obtained in (2) in a -20 °C refrigerator for 48 hours to obtain a dry CS / CA hydrogel.

[0120] (4) Add aloin (Alo) to ultralight water (DDW) to prepare an aloin solution with a concentration of 8 mg / mL.

[0121] (5) Immerse the hydrogel in step (3) into the solution in step (4) for 12 hours.

[0122] (6) Place the hydrogel in step (5) in a -20°C refrigerator and freeze-dry for 48 hours.

[0123] Comparative Example 1

[0124] The difference from Example 3 is that in this comparative example, the CS / CA hydrogel is not immersed in the aloin solution, that is, steps (4)-(6) in S2 are not included.

[0125] Comparative Example 2

[0126] The hydrogel dressing in this comparative example does not include caffeic acid and is not immersed in the aloin solution. The specific steps are as follows:

[0127] (1) Dissolve 400 mg of chitosan, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0128] (2) Pour the mixture in step (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0129] (3) Freeze and freeze-dry the hydrogel in step (2) in a -20°C refrigerator for 48 hours to obtain a dry pure chitosan hydrogel.

[0130] Comparative Example 3

[0131] The hydrogel dressing in this comparative example does not include caffeic acid but is immersed in the aloin solution. The specific steps are as follows:

[0132] (1) Dissolve 400 mg of chitosan, 200 mg of n-hydroxysuccinimide acrylate (AAC-NHS), and 40 mg of α-ketoglutaric acid in 6 ml of acrylic acid to obtain a light yellow transparent solution, and then fill the solution to 20 ml with deionized water and stir evenly.

[0133] (2) Pour the mixture in step (1) into a polytetrafluoroethylene mold and cure it with a UV LED lamp (365 nm, 10 W power) for 30 minutes.

[0134] (3) Freeze and freeze-dry the hydrogel in step (2) in a -20°C refrigerator for 48 hours to obtain a dry pure chitosan hydrogel.

[0135] (4) Aloin (Alo) was added to deionized water (DDW) to prepare an aloin solution with a concentration of 8 mg / mL.

[0136] (5) The hydrogel prepared in (3) was immersed in the solution prepared in (4) for 12 hours.

[0137] (6) The hydrogel obtained in (5) was placed in a -20 °C refrigerator and freeze-dried for 48 hours.

[0138] Experimental Examples

[0139] The hydrogels prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to adhesion mechanics tests, antibacterial tests, and antioxidant tests.

[0140] 1. Adhesion Mechanics Test

[0141] To test the adhesion performance of the hydrogels, after loading 1 cm^2 of CS, CS / CA, CS / CA / Alo-2, 4, 6, and 8 hydrogels onto a piece of porcine buccal mucosa, another piece of buccal mucosa was covered on it. The overlapping area was 1 cm × 1 cm. Then, the hydrogels were wetted with 1×PBS, and the buccal mucosa was fixed on a rod connected to a load cell. The lap shear strength of several prepared hydrogels was tested using an electronic universal material testing machine (Instron 5967, USA). The samples were uniaxially stretched at a rate of 0.5 mm / s until the hydrogels broke. The same experiment for each sample was repeated 3 times.

[0142] The results of the adhesion mechanics test are as Figure 1 shown, where CS / CA / Alo-2 represents the hydrogel dressing of Example 1, CS / CA / Alo-4 represents the hydrogel dressing of Example 2, CS / CA / Alo-6 represents the hydrogel dressing of Example 3, CS / CA / Alo-8 represents the hydrogel dressing of Example 4, CS / CA represents the hydrogel dressing of Comparative Example 1, CS represents the hydrogel dressing of Comparative Example 2, and CS / Alo represents the hydrogel dressing of Comparative Example 3.

[0143] According to Figure 1 the results, compared with Comparative Examples 1-3, the bonding strength of Examples 1-4 after soaking in aloin solution was significantly enhanced, about 2-5 times that of Comparative Examples 1-3, and with the increase in the concentration of aloin solution in Examples 1-4, the bonding strength also showed an increasing trend.

[0144] The hydrogel dressing in Example 3 was subjected to adhesion tests for different parts and different bending degrees, and the test results are as Figure 2 . It can be seen from the figure that the hydrogel dressing prepared by the present invention is adaptable to the skin surface. Whether it is joints with large movement amplitudes such as the wrist or knuckles, the hydrogel dressing prepared by the present invention can provide firm adhesion.

[0145] Meanwhile, the hydrogel dressings in Example 3 were subjected to adhesion tests on different materials, and the test results are as Figure 3 shown. Among them, a represents the heart of a mouse, b represents the liver of a mouse, c represents the spleen of a mouse, d represents the lung of a mouse, e represents the kidney of a mouse, f represents a plastic material, g represents a glass material, and h represents a metal material. It can be seen from the figure that the hydrogel dressing of the present invention has various adhesion properties, and not only has a strong adhesion effect on the skin, but also has a good adhesion effect on internal organs and even plastic, glass and metal materials.

[0146] 2. Antibacterial test

[0147] The antibacterial test includes anti-Staphylococcus aureus and Escherichia coli. The test method is as follows: Staphylococcus aureus and Escherichia coli were selected as representatives of Gram-positive and Gram-negative bacteria for in vitro antibacterial tests. Bacteria were isolated on LB agar (LBA) solid plates, and single colonies were inoculated into LB medium and cultured at 37 °C for 18 h. Then, the colonies taken from the LBA solid plates were incubated in a shaker (150 rpm / min) of 10 mL of fresh LB medium at 37 °C for 18 h. Subsequently, the obtained bacterial suspension was diluted to 2×10^5 CFU / mL, and equal volumes of extracts of different hydrogels were mixed and incubated in a bacterial incubator for 24 hours. 100 μL of the co-culture solution was taken out and diluted to an appropriate concentration, and then the diluted solution was spread on the LBA solid medium and placed in a bacterial incubator at 37 °C for 24 hours. The number of colonies in each group was counted. The relative bacterial activity was calculated as follows:

[0148]

[0149] where CFUSample and CFUcontrol are the number of colonies in the hydrogel group and the control group, respectively. All measurements were repeated three times.

[0150] The results of the anti-Staphylococcus aureus and Escherichia coli tests are as Figures 4 - 7 shown. PCG-Alo 2 mg / ml represents the hydrogel dressing prepared in Example 1, PCG-Alo 4 mg / ml represents the hydrogel dressing prepared in Example 2, PCG-Alo 6 mg / ml represents the hydrogel dressing prepared in Example 3, PCG-Alo 8 mg / ml represents the hydrogel dressing prepared in Example 4, control represents the blank control, CG represents Comparative Example 2, and PCG represents Comparative Example 1. It can be seen from the figure that Examples 1-4 and Comparative Examples 1-2 all have inhibitory effects on Staphylococcus aureus and Escherichia coli, but compared with Comparative Examples 1-2, Examples 1-4 have better antibacterial effects, especially Example 3, with more significant effects.

[0151] 3. Antioxidant experiment

[0152] The determination of intracellular antioxidants was carried out using a reactive oxygen species assay kit (Beyotime, China). Hydrogels were prepared in 6-well plates, and cells were seeded on the surface of the hydrogels (2×10^5 cells / well) and incubated for 24 hours. Then Rosup (positive control reagent) was added to each well and incubated for another 2 hours, and then treated with diluted DCFH-DA (10 μM) to load the fluorescent probe into the cells. The results were analyzed using LAS X software.

[0153] Figure 8 Images of ROS determination for L929 and HUVEC cells, Figure 9 is the fluorescence quantitative statistics of ROS determination for L929 and HUVEC cells. It can be concluded from Figures 8 - 9 that compared with Comparative Examples 1-2, CS / CA / Alo-2, 4, 6, and 8 hydrogels all have better antioxidant effects.

[0154] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an antibacterial hydrogel dressing with multiple adhesive properties, characterized in that, Comprising: React chitosan with caffeic acid to prepare a CS / CA polymer; Then cure the CS / CA polymer to form a CS / CA hydrogel, and immerse the CS / CA hydrogel in an aloenin solution, and after drying, the antibacterial hydrogel wound dressing is obtained; Wherein, the concentration of aloenin in the aloenin solution is 2 - 8 mg / mL; The preparation steps of the CS / CA hydrogel include: dissolving the CS / CA polymer, n-hydroxysuccinimide acrylate and α-ketoglutaric acid in an acrylic acid solution, mixing evenly, curing, and freeze-drying to obtain the CS / CA hydrogel.

2. The preparation method of the antibacterial hydrogel dressing according to claim 1, characterized in that, The steps of preparing the CS / CA polymer include adjusting the pH, dialyzing, and freeze-drying the mixed solution after mixing the chitosan solution and the solution containing caffeic acid.

3. The preparation method of the antibacterial hydrogel dressing according to claim 2, wherein, Adjust the pH of the mixed solution to 4.5 - 5.

0.

4. The preparation method of the antibacterial hydrogel dressing according to claim 2, characterized in that, The dialysis includes first performing the first dialysis of the mixed solution in a dialysis solution containing sodium chloride, and then performing the second dialysis in an ultralight water dialysis solution.

5. The preparation method of the antibacterial hydrogel dressing according to claim 4, characterized in that, In the first dialysis, the pH of the dialysis solution is 4 - 4.5, the concentration of sodium chloride is 10 mmol, and the dialysis time is 48 h; the time of the second dialysis is 4 h.

6. The preparation method of the antibacterial hydrogel dressing according to claim 2, characterized in that, The temperature of the freeze-drying is -20 °C, and the time is 36 - 48 h.

7. The preparation method of the antibacterial hydrogel wound dressing according to claim 2, characterized in that, The molecular weight of chitosan in the chitosan solution is: 50000 - 190000, and the degree of deacetylation is 75 - 85; the pH of the chitosan solution is 5 - 5.

5.

8. The preparation method of the antibacterial hydrogel dressing according to claim 7, characterized in that, The mass ratio of chitosan to caffeic acid is 1:1.

18.

9. The preparation method of the antibacterial hydrogel dressing according to claim 8, characterized in that, The solute in the solution containing caffeic acid further includes carbodiimide and N-hydroxysulfosuccinimide, and the solvent is ethanol.

10. The preparation method of the antibacterial hydrogel dressing according to claim 9, characterized in that, The mass ratio of caffeic acid, carbodiimide and N-hydroxysulfosuccinimide contained in every 20 ml of ethanol in the solution containing caffeic acid is: 1.18:1.25:0.

748.

11. The preparation method of the antibacterial hydrogel dressing according to claim 1, characterized in that, The soaking time of the CS / CA hydrogel in the aloenin solution is 10 - 12 h.

12. The preparation method of the antibacterial hydrogel dressing according to claim 11, wherein In every 1 mL of acrylic acid solution, the mass ratio of the CS / CA polymer, n-hydroxysuccinimide acrylate and α-ketoglutaric acid is 20:10:

2.

13. The preparation method of the antibacterial hydrogel dressing according to claim 12, characterized in that, The volume concentration of the acrylic acid solution is 30%.

14. The preparation method of the antibacterial hydrogel dressing according to claim 13, characterized in that, The curing time is 20 - 30 min.

15. The preparation method of the antibacterial hydrogel dressing according to claim 14, characterized in that, The temperature of the freeze-drying is -20 °C, and the time is 36 - 48 h.

16. An antibacterial hydrogel dressing prepared by the preparation method of the antibacterial hydrogel dressing according to any one of claims 1 - 15.

Images