A double-dynamic cross-linked polyacrylamide / gelatin / PDA-Zn2+ hydrogel as well as a preparation method and application thereof

Abstract

The application discloses a kind of double dynamic crosslinking polyacrylamide / gelatin / PDA-Zn 2+ Hydrogel and its preparation method and application. The preparation method comprises the following steps: first, dopamine is dissolved in water, and the alkaline oxygen-containing environment is adjusted to make dopamine pre-polymerize to obtain a polydopamine solution; then, gelatin is added into the polydopamine solution and heated to dissolve; subsequently, acrylamide and zinc ions are added in sequence; and finally, double dynamic crosslinking polyacrylamide / gelatin / PDA-Zn is obtained through free radical polymerization under the action of an initiator, a crosslinking agent and a co-initiator. 2+ Hydrogel. In the hydrogel, polydopamine forms a Schiff base and a hydrogen bond with gelatin and polyacrylamide, and Zn 2+ forms a coordination bond with polydopamine to form double dynamic crosslinking. The prepared hydrogel has excellent mechanical properties, self-adhesion and antibacterial properties, good biocompatibility, and can be widely applied in the field of biomedical materials.

Description

Technical Field

[0001] This invention belongs to the field of biopolymer materials technology, and specifically relates to a dual dynamic crosslinked polyacrylamide / gelatin / PDA-Zn 2+ Hydrogels, their preparation methods, and applications. Background Technology

[0002] The skin is the largest organ in the human body, playing a vital role in maintaining homeostasis and protecting internal organs from external environmental influences. When the skin is damaged by external factors such as surgery, physical force, heat, or low temperatures, wounds form, and the damaged skin loses its protective barrier function. Improper treatment can lead to skin infections, worsening of skin damage, and even death.

[0003] Hydrogels are three-dimensional network materials formed by the physical or chemical cross-linking of polymers or other molecules, containing a large amount of water. Due to their similar structure and properties to human tissue, and their advantages such as maintaining a moist wound environment, breathability, and absorption of exudate, hydrogels have always been a research hotspot in the biomedical field. A suitable hydrogel dressing can provide a favorable environment for the healing of damaged skin wounds.

[0004] A crucial aspect of wound healing is preventing infection, as infections caused by bacteria and environmental microorganisms significantly slow down the healing process. Developing hydrogel dressings with antibacterial and anti-infective properties can improve wound healing efficiency. Currently, hydrogels with antibacterial properties are generally drug-loaded or contain silver nanoparticles. However, the addition of drugs can lead to issues such as drug resistance, and the safety of silver nanoparticles loaded into hydrogels remains highly controversial.

[0005] During the healing process, wounds are in motion, and hydrogels on the wound surface will inevitably be stretched and bent. However, antibacterial hydrogels often lack sufficient mechanical properties and adhesion, making them unsuitable for complex wound types. In addition, antibacterial hydrogels also suffer from high costs and cumbersome preparation processes. Summary of the Invention

[0006] To overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a dual dynamic crosslinked polyacrylamide / gelatin / PDA-Zn 2+ Hydrogels and their preparation methods were developed, resulting in a hydrogel wound dressing with good biocompatibility, good mechanical properties, and antibacterial properties.

[0007] Another object of the present invention is to provide a polyacrylamide / gelatin / PDA-Zn prepared by the above method. 2+ Applications of hydrogels in the field of biomedical materials.

[0008] The objective of this invention is achieved through the following solution:

[0009] A dual dynamic crosslinked polyacrylamide / gelatin / PDA-Zn 2+ The preparation method of the hydrogel includes: first, dissolving dopamine in water, adjusting the alkaline oxygen-containing environment to prepolymerize the dopamine to obtain a polydopamine solution, adding gelatin to the polydopamine solution and heating to dissolve it, then sequentially adding acrylamide and zinc ions, and undergoing free radical polymerization under the action of an initiator, a crosslinking agent, and a co-initiator to obtain a bidynamically crosslinked polyacrylamide / gelatin.

[0010] / PDA-Zn 2+ Hydrogel (PAM-Gel-PDA-Zn) 2+ ).

[0011] Preferably, the mass ratio of acrylamide, gelatin and polydopamine is 4:1:(0.04-0.08); more preferably, it is 4:1:(0.06-0.08).

[0012] Preferably, adjusting the alkaline oxygen-containing environment to prepolymerize dopamine specifically includes: adjusting the pH of the solution to 8-11 with NaOH solution, and stirring at room temperature in the dark for 0.2-1 h, more preferably 0.5-1 h.

[0013] More preferably, the added zinc ions are derived from ZnCl2, and the mass ratio of the added ZnCl2 to acrylamide is (0.1-1):400; more preferably, it is (0.5-1):400.

[0014] Preferably, the gelatin is heated to dissolve at a temperature of 55–60°C for 20–30 minutes.

[0015] More preferably, the concentration of the gelatin in the polydopamine solution is 5 g / 100 mL.

[0016] Preferably, the initiator can be a conventionally used initiator in polymerization reactions, such as ammonium persulfate, potassium persulfate, sodium persulfate, etc., and more preferably, ammonium persulfate is used as the initiator. And / or the mass ratio of the initiator to acrylamide is preferably (0.2-0.5):4, more preferably (0.3-0.4):4.

[0017] Preferably, the crosslinking agent can be a crosslinking agent commonly used in polymerization reactions, such as N,N-methylenebisacrylamide, polyethylene glycol diacrylate, or dicumyl peroxide; more preferably, N,N-methylenebisacrylamide is used as the crosslinking agent. And / or the mass ratio of the crosslinking agent to acrylamide is preferably (0.01–0.02):4, more preferably (0.015–0.02):4.

[0018] Preferably, the co-initiator is tetramethylethylenediamine. And / or the amount (volume) of the co-initiator is preferably 0.1% to 0.5% of the total volume of the reaction system, more preferably 0.1%.

[0019] Preferably, the initiator, crosslinking agent and co-initiator are stirred evenly after being added to the system, more preferably stirred for 1 to 5 minutes.

[0020] The preparation method of this invention first induces dopamine polymerization in an alkaline oxygen-containing environment to form polydopamine. The prepolymerization reaction time is short, avoiding excessive oxidation of dopamine and maintaining a sufficient number of free phenolic hydroxyl groups in the hydrogel, resulting in hydrogels with strong tissue adhesion and good cell affinity. Then, gelatin, acrylamide, and Zn are added... 2+ When added to a polydopamine solution, it undergoes free radical polymerization under the action of an initiator, crosslinking agent, and co-initiator to form polyacrylamide / gelatin / PDA-Zn. 2+ Hydrogel.

[0021] This invention also provides polyacrylamide / gelatin / PDA-Zn prepared by the above method. 2+ Hydrogels possess excellent mechanical properties, self-adhesion and antibacterial properties, and good biocompatibility.

[0022] The present invention also provides the above-mentioned polyacrylamide / gelatin / PDA-Zn 2+ Applications of hydrogels in the field of biomedical materials.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] The preparation method of this invention has mild reaction conditions, short preparation time, and is simple and easy to control.

[0025] The raw materials for this invention are abundant and inexpensive.

[0026] This invention constructs a novel composite antibacterial hydrogel integrating multiple functional components through free radical copolymerization, which has good mechanical properties, self-adhesion and antibacterial properties.

[0027] The polyacrylamide / gelatin / PDA-Zn prepared by this invention 2+ Hydrogels have good biocompatibility and are promising for a wide range of applications in biomedical materials. Attached Figure Description

[0028] Figure 1 The polyacrylamide / gelatin / PDA-Zn prepared in Example 1 2+ Scanning electron microscope image of the cross-section of the hydrogel after freeze-drying.

[0029] Figure 2 Tensile stress-strain diagrams for different hydrogels in Test Example 1.

[0030] Figure 3 The diagram shows the equilibrium swelling ratios of different hydrogels in Test Example 1.

[0031] Figure 4 For example, in test example 2, polyacrylamide / gelatin / PDA-Zn 2+ Hydrogel (PGD-Zn) 2+ Adhesion properties on different material surfaces.

[0032] Figure 5 The results of the cell compatibility test for different hydrogels in Test Example 3 are shown. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. The materials involved in the following embodiments are all commercially available.

[0034] In this application, "room temperature" can be "25℃±5℃".

[0035] Example 1

[0036] (1) Weigh 0.06g of dopamine and dissolve it in 20mL of water. Adjust the pH of the solution to 11 with NaOH solution and stir for 1h at room temperature in the dark to allow DA to prepolymerize and form PDA.

[0037] (2) Weigh 1g of gelatin and add it to the PDA solution in step (1). Heat to 60℃ and stir for 30min. Then add 4g of acrylamide and 0.01g of zinc chloride, followed by 0.4g of ammonium persulfate, 0.02g of N,N-methylenebisacrylamide, and finally 20μL of tetramethylethylenediamine. Stir for 3 minutes and then stop. The solution undergoes a free radical polymerization reaction to generate polyacrylamide / gelatin / PDA-Zn. 2+ Hydrogel (PGD-Zn) 2+ ).

[0038] The prepared polydopamine / gelatin / polyacrylamide / PDA-Zn 2+ The hydrogel was freeze-dried and then examined cross-sectionally using scanning electron microscopy. The results are as follows: Figure 1 As shown. By Figure 1 It is evident that the gel has a porous internal structure, which facilitates the provision of a matrix for cell growth and the easier delivery of nutrients to the cells, thus promoting better cell growth.

[0039] Comparative Example 1: Preparation of Polyacrylamide / Gelatin / PDA Hydrogel

[0040] (1) Weigh 0.06g of dopamine and dissolve it in 20mL of water. Adjust the pH of the solution to 11 with NaOH solution and stir for 1h at room temperature in the dark to allow DA to prepolymerize and form PDA.

[0041] (2) Weigh 1g of gelatin and add it to the PDA solution in step (1). Heat to 60℃ and stir for 30min. Then add 4g of acrylamide, followed by 0.4g of ammonium persulfate, 0.02g of N,N-methylenebisacrylamide, and finally 20μL of tetramethylethylenediamine. Stop stirring after 3 minutes. The solution undergoes free radical polymerization to generate polyacrylamide / gelatin / PDA hydrogel (PGD).

[0042] Comparative Example 2: Preparation of Polyacrylamide / Gelatin Hydrogel

[0043] Weigh 0.06g of gelatin and add it to 20mL of water. Heat to 60℃ and stir for 30min to dissolve the gelatin. Then add 4g of acrylamide, followed by 0.4g of ammonium persulfate, 0.02g of N,N-methylenebisacrylamide, and finally 20μL of tetramethylethylenediamine. Stir for 3 minutes and then stop. The solution undergoes a free radical polymerization reaction to generate polyacrylamide / gelatin hydrogel (PG).

[0044] Comparative Example 3: Preparation of Polyacrylamide Hydrogel

[0045] Weigh 4g of acrylamide and dissolve it in 20mL of water. Then add 0.4g of ammonium persulfate, 0.02g of N,N-methylenebisacrylamide, and finally 20μL of tetramethylethylenediamine. Stir for 3 minutes and then stop. The solution undergoes a free radical polymerization reaction to generate polyacrylamide / gelatin hydrogel (PAM).

[0046] Test Example 1: Mechanical Properties and Swelling Properties Test

[0047] Mechanical properties and swelling properties were tested on the hydrogels prepared in Example 1 and the hydrogels prepared in Comparative Examples 1-3.

[0048] Mechanical property testing: Three identical samples of each of the four types of hydrogels were taken and their tensile properties were tested using an electronic universal testing machine (model GP-6113A). The compression rate was 2 mm / min, and the hydrogel compression was 70%. Stress-strain diagrams were plotted, and the results are shown below. Figure 2 As shown. From Figure 2 It can be seen that the polyacrylamide / gelatin / PDA-Zn prepared by this invention 2+ The hydrogel exhibits a tensile strain of approximately 450% and a maximum tensile stress of 12.25 kPa. Therefore, the polyacrylamide / gelatin / PDA-Zn of this invention... 2+Hydrogels have excellent mechanical properties, which can meet the mechanical performance requirements of wound dressings.

[0049] Swelling performance test: Three samples of the same volume for each of the four types of hydrogels were taken and freeze-dried. The original weight of the samples was weighed and recorded. The samples were then placed in PBS buffer (pH 7.4) for swelling rate testing, and then placed on a shaker at 37°C. After a certain period of time, the samples were removed, the surface moisture was blotted dry with filter paper, and the samples were weighed immediately. The samples were weighed at 24 and 48 hours, respectively. The swelling rate of the hydrogels was calculated using the formula ESR = (Ws - Wd) / Wd × 100%, and a swelling rate-time graph was plotted. Where ESR: equilibrium swelling ratio, Wd: initial freeze-dried hydrogel mass, and Ws: mass of the swollen hydrogel. The results are shown in the figure. Figure 3 .from Figure 3 It can be seen that the polyacrylamide / gelatin / PDA-Zn prepared by this invention 2+ The hydrogel exhibits an equilibrium swelling ratio of 1108% after 24 hours and 1603% after 48 hours. This demonstrates that the polyacrylamide / gelatin / PDA-Zn of this invention... 2+ Hydrogels have excellent water absorption and swelling properties, which can absorb wound exudate and meet the requirements of wound dressings.

[0050] Test Example 2: Polyacrylamide / Gelatin / PDA-Zn 2+ Hydrogel sensory adhesion test

[0051] The hydrogel prepared in Example 1 was cut into cuboids 1.5 cm long, 1.5 cm wide, and 2 mm thick. These cuboids were placed on glass, wood, a crucible, and rubber, respectively, and pressed for 2 minutes. The results are shown below. Figure 4 As shown in the figure, the prepared hydrogel exhibits good adhesion, enabling it to adhere to the surfaces of different materials, thus meeting the adhesion requirements of hydrogels.

[0052] Test Example 3: Cell Compatibility Test

[0053] The hydrogels prepared in Example 1 and those prepared in Comparative Examples 1-3 were subjected to cell compatibility testing (MTT method). The specific steps are as follows:

[0054] (A) Resuscitate mouse embryonic fibroblasts (NIH / 3T3), collect cells in the logarithmic growth phase, adjust the cell suspension concentration, and divide them into 96-well plates at a cell concentration of 1×10⁻⁶. 4 The number of holes per well is divided into two time groups: 24 hours and 48 hours.

[0055] (B) The hydrogel was sterilized by soaking in 70% alcohol, and then soaked in the extraction solution for 24 hours.

[0056] (C) After incubating at 37°C for 12 hours with 5% CO2, replace the culture medium with 200 μL of hydrogel extract.

[0057] (D) After a further 48-hour incubation, 20 μL MTT solution was added to each well and incubated for 4 hours. (E) Finally, the culture medium was replaced with 200 μL LDMSO, and the samples were analyzed using a microplate reader (Biorad, USA) with an excitation wavelength of 490 nm. Cell viability was calculated using the formula: Cell viability (%) = [A(drug-added) - A(blank)] / [A(0-drug-added) - A(blank)] × 100%, where A(drug-added): OD value of wells containing cells, CCK-8 solution, and drug solution; A(0-drug-added): OD value of wells containing cells and MTT solution but no drug solution; A(blank): OD value of wells without cells. Cell viability: Cell proliferation activity or cytotoxic activity.

[0058] Test results are as follows Figure 4 As shown in the MTT cell proliferation assay, the cell viability of all four hydrogels was greater than 80% at 24 and 48 hours, indicating good cell compatibility, which meets the biocompatibility requirements for wound dressings.

[0059] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A dual dynamic crosslinked polyacrylamide / gelatin / PDA-Zn 2+ Methods for preparing hydrogels include: First, dopamine is dissolved in water to adjust the alkaline oxygen-containing environment for prepolymerization, resulting in a polydopamine solution. Gelatin is then added to the polydopamine solution and heated to dissolve. Acrylamide and zinc ions are then added sequentially. Under the action of an initiator, crosslinking agent, and co-initiator, free radical polymerization is performed to obtain a bidynamically crosslinked polyacrylamide / gelatin / PDA-Zn. 2+ The hydrogel contains acrylamide, gelatin, and polydopamine in a mass ratio of 4:1:(0.04~0.08). The added zinc ions are derived from ZnCl2, and the mass ratio of ZnCl2 to acrylamide is (0.1~1):

400. The initiator includes ammonium persulfate, potassium persulfate, and sodium persulfate. The mass ratio of the initiator to acrylamide is (0.2~0.5):

4. The crosslinking agent includes N,N-methylenebisacrylamide, polyethylene glycol diacrylate, and dicumyl peroxide. The mass ratio of the crosslinking agent to acrylamide is (0.01~0.02):

4.

2. The preparation method according to claim 1, characterized in that, The process of adjusting the alkaline oxygen-containing environment to prepolymerize dopamine specifically includes: adjusting the pH of the solution to 8-11 with NaOH solution and stirring at room temperature in the dark for 0.2-1 h.

3. The preparation method according to claim 1, characterized in that, The gelatin is heated to dissolve at a temperature of 55-60°C for 20-30 minutes.

4. The preparation method according to claim 1, characterized in that, The co-initiator is tetramethylethylenediamine; and / or the amount of the co-initiator is 0.1-0.5% of the total volume of the reaction system.

5. A polyacrylamide / gelatin / PDA-Zn 2+ The hydrogel is prepared by the preparation method according to any one of claims 1 to 4.

6. The polyacrylamide / gelatin / PDA-Zn as described in claim 5 2+ Applications of hydrogels in the field of biomedical materials.

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