阅读说明：本技术 一种柔性导电抗菌材料及其制备方法 (Flexible conductive antibacterial material and preparation method thereof ) 是由 张婕妤 胡雪丰 王云兵 武璨 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种柔性导电抗菌材料及其制备方法,属于柔性生物电子材料领域。解决了现有技术中使用硬质电极难以刺激整个伤口,并且ES疗法缺乏控制感染的能力等问题。本发明制备了聚苯胺-磺酸透明质酸(SHA)水凝胶。在弱碱性生理条件下,水凝胶网络中的SHA可以原位掺杂聚苯胺并维持其导电性,掺杂的PANI带正电荷,对革兰氏阳性菌具有较强的抗菌活性。此外,外源ES能增强水凝胶的抗菌活性。本发明制备的水凝胶能够完全覆盖伤口,具有与人体组织类似的导电性、良好的生物相容性与抗菌性,可以用来制备柔性导电敷料等产品。(The invention discloses a flexible conductive antibacterial material and a preparation method thereof, belonging to the field of flexible bioelectronic materials. Solves the problems that the whole wound is difficult to stimulate by using a hard electrode in the prior art, and the ES therapy lacks the capability of controlling infection, and the like. The invention prepares polyaniline-sulfonic acid hyaluronic acid (SHA) hydrogel. Under alkalescent physiological conditions, SHA in the hydrogel network can be doped with polyaniline in situ and maintain the conductivity of the polyaniline, and the doped PANI has positive charges and has strong antibacterial activity on gram-positive bacteria. In addition, exogenous ES can enhance the antimicrobial activity of the hydrogel. The hydrogel prepared by the invention can completely cover wounds, has conductivity similar to human tissues, good biocompatibility and antibacterial property, and can be used for preparing products such as flexible conductive dressings and the like.)

1. The preparation method of the flexible conductive antibacterial material is characterized by comprising the following steps of:

step 1: adding 0.5-1g HA into 100ml solvent to prepare HA solution, adding 0.5-1g NaIO into 30ml solvent₄Prepared into NaIO₄Solution, mixing HA solution with NaIO₄Solution mixingStirring for 3-7 h at room temperature under the condition of no light, adding ethylene glycol into the mixed solution to quench unreacted NaIO₄Stirring for 2-3 h, and removing sodium iodate and formaldehyde to obtain OHA;

step 2: preparing 0.5-1.5 wt% OHA solution, preparing 3-7 wt% NaHSO₃Solution, OHA solution and NaHSO₃Mixing the solution, OHA solution and NaHSO₃The volume ratio of the solution is 5: reacting at 45-60 ℃ for 4-6 h, and dialyzing to obtain SHA;

and step 3: dissolving SHA, acrylamide and a crosslinking agent in water, adding a thermal initiator and an accelerator to obtain a mixed solution, injecting the mixed solution into a mold, reacting for 2-6 h at 30-60 ℃, and annealing for 10-14 h at room temperature to obtain PS hydrogel, wherein the mass ratio of the SHA to the acrylamide is 1: 7-10, the dosage of the crosslinking agent is 0.1-0.3 wt% of the reaction system, the dosage of the initiator is 0.1-0.3 wt% of the reaction system, and the dosage of the accelerator is 0.1-0.3 wt% of the reaction system;

and 4, step 4: and (3) soaking the PS hydrogel into 50mL of solution containing 1.0M acid and 15-30 mM aniline for 20-30h, then adding 15-30 mmol APS, and reacting for 2-6 h to obtain the PSP hydrogel.

2. The method for preparing the flexible conductive antibacterial material according to claim 1, wherein in the step 1, the amount of HA is 0.7g, the amount of NaIO4 is 0.6g, and the reaction time is 5 h.

3. The method for preparing a flexible conductive antibacterial material according to claim 1, wherein sodium iodate and formaldehyde are removed by dialysis in step 1.

4. The method for preparing a flexible conductive antibacterial material according to claim 1, wherein in the step 2, the amount of OHA is 0.1 wt% of the reaction system; NaHSO₃The using amount is 5 wt% of the reaction system; the reaction temperature is 50 ℃; the reaction time was 5 h.

5. The method for preparing the flexible conductive antibacterial material according to claim 1, wherein in the step 3, the mass ratio of SHA to acrylamide is 1: 9; the cross-linking agent is MBAA, and the using amount of the cross-linking agent is 0.15 wt% of the reaction system; the initiator is ammonium persulfate, and the using amount of the initiator is 0.2 wt% of the reaction system; the accelerant is N, N, N ', N' -tetramethyl ethylenediamine, and the using amount of the accelerant is 0.2 wt% of the reaction system; the reaction temperature is 40 ℃; the reaction time was 4h and the annealing time was 12 h.

6. The method for preparing a flexible conductive antibacterial material according to claim 5, wherein the acid in step 4 is one of hydrochloric acid, acetic acid, oxalic acid and nitric acid, and the concentration of the aniline solution is 25 mM; the dosage of ammonium persulfate is 25 mmol; the reaction time was 4 h.

7. A flexible conductive antibacterial material, characterized by being prepared by the preparation method of any one of claims 1 to 6.

Technical Field

The invention belongs to the field of biological materials, and particularly relates to a flexible conductive antibacterial material and a preparation method thereof.

Background

Wounds that fail to heal within 3 months may deteriorate into chronic wounds, seriously threatening human health. Chronic wounds include diabetic foot ulcers, venous leg ulcers and pressure sores. Along with the aging of population, weight increase and increasingly secondary complications of diabetes, venous insufficiency and other diseases, the number of patients suffering from chronic wounds is remarkably increased. It is estimated that about 1% of people may develop leg ulcers during their lifetime. In the United states alone, there are 300-600 million chronic wounds per year, with costs of treatment approaching $ 50-100 million. In china, the rate of chronic wounds in surgical hospitalized patients is about 1.5% to 20.3% according to epidemiological studies, which imposes a great economic burden on public health systems and society.

The microenvironment of a chronic wound contains debris of necrotic tissue, facilitating bacterial attachment and growth. The attached bacteria can proliferate to form a biofilm that subsequently diffuses to surrounding tissues, developing a systemic infection. Wound infection prolongs inflammation and delays healing, while wounds heal slowly, which in turn increases the risk of bacterial infection, further impeding healing. In extremely life-threatening cases, amputation of the distal limb is required.

The management of infection is critical to chronic wound management, and commonly used clinical techniques include careful debridement, antibiotic use, and topical antibacterial therapy. However, current techniques remain a significant challenge to combat biofilm-induced infections. Surgical debridement does not completely remove bacteria from the wound, and in most cases biofilms reappear within 3 days. Chronic use of antibiotics can cause antibiotic resistance and other adverse side effects of bacteria, including gastrointestinal symptoms, skin rashes, thrush, impairment of mitochondrial function. Therefore, researchers are looking for new antibiotics that can replace traditional antibiotics.

Positively charged substances are promising antimicrobial agents due to their low potential for developing bacterial resistance and high antimicrobial efficacy. Electrostatic attraction between positively charged antimicrobial agents and negatively charged bacterial cells can damage the cell wall, resulting in cytoplasmic leakage. However, commonly used cationic antimicrobial agents have several limitations in biomedical applications, such as toxicity (e.g., Ag +) and high cost (e.g., specially designed antimicrobial peptides).

In addition to treating infections, another challenge in chronic wound therapy is accelerating wound closure. Current clinical strategies include debridement, negative pressure therapy and flap repair. However, these treatments have at least one disadvantage, namely, long treatment time, high cost and poor therapeutic effect. In contrast, Electrical Stimulation (ES) therapy is receiving increasing attention because of its effectiveness, low cost, and safety. However, clinically used ES devices deliver stimulation to the wound through rigid electrodes and do not fully conform to the soft wound tissue. Thus, the current cannot stimulate the entire wound area, especially large irregularly shaped wounds. And the existing material lacks antibacterial performance and has poor effect on infected chronic wounds.

Disclosure of Invention

Aiming at the problems that the whole wound is difficult to stimulate by using a hard electrode and the ES therapy lacks the capability of controlling infection and the like in the prior art, the invention provides a flexible conductive antibacterial material and a preparation method thereof, and aims to provide a flexible conductive antibacterial material and a preparation method thereof, wherein the flexible conductive antibacterial material comprises the following components: .

For simplicity of description, the following terms are abbreviated herein:

ES: electrical stimulation; HA: hyaluronic acid; an OHA: oxidized hyaluronic acid; SHA: sulfonated hyaluronic acid; PANI: polyaniline; MBAA: n, N' -methylenebisacrylamide, NaIO₄: sodium iodate.

The technical scheme adopted by the invention is as follows:

a preparation method of a flexible conductive antibacterial material comprises the following steps:

step 1: adding 0.5-1g HA into 100ml solvent to prepare HA solution, adding 0.5-1g NaIO into 30ml solvent₄Prepared into NaIO₄Solution, mixing HA solution with NaIO₄Mixing the solutions, stirring for 3-7 h at room temperature under the condition of no light, adding ethylene glycol into the mixed solution to quench unreacted NaIO₄Stirring for 2-3 h, and removing sodium iodate and formaldehyde to obtain OHA;

step 2: preparing 0.5-1.5 wt% OHA solution, preparing 3-7 wt% NaHSO₃Solution, OHA solution and NaHSO₃Mixing the solution, OHA solution and NaHSO₃The volume ratio of the solution is 5: reacting at 45-60 ℃ for 4-6 h, and dialyzing to obtain SHA;

and step 3: dissolving SHA, acrylamide and a crosslinking agent in water, adding a thermal initiator and an accelerator, injecting the solution into a mold, reacting for 2-6 h at 30-60 ℃, and annealing at room temperature for 10-14 h to obtain PS hydrogel, wherein the mass ratio of the SHA to the acrylamide is 1: 7-10, the dosage of the crosslinking agent is 0.1-0.3 wt% of the reaction system, the dosage of the initiator is 0.1-0.3 wt% of the reaction system, and the dosage of the accelerator is 0.1-0.3 wt% of the reaction system;

and 4, step 4: and (3) soaking the PS hydrogel into 50mL of solution containing 1.0M acid and 15-30 mM aniline for 24h, then adding 15-30 mmol APS, and reacting for 2-6 h to obtain the PSP hydrogel.

Preferably, in step 1, HA is used in an amount of 0.7g, NaIO₄The amount used was 0.6g and the reaction time was 5 h.

Preferably, sodium iodate and formaldehyde are removed by dialysis in step 1.

Preferably, in step 2, OHA is used in an amount of 0.1 wt% based on the reaction system; NaHSO₃The using amount is 5 wt% of the reaction system; the reaction temperature is 50 ℃; the reaction time was 5 h.

Preferably, in the step 3, the mass ratio of the SHA to the acrylamide is 1: 9; the cross-linking agent is MBAA, and the using amount of the cross-linking agent is 0.15 wt% of the reaction system; the initiator is ammonium persulfate, and the using amount of the initiator is 0.2 wt% of the reaction system; the accelerant is N, N, N ', N' -tetramethyl ethylenediamine, and the using amount of the accelerant is 0.2 wt% of the reaction system; the reaction temperature is 40 ℃; the reaction time was 4h and the annealing time was 12 h.

Preferably, the acid in the step 4 is one of hydrochloric acid, acetic acid, oxalic acid and nitric acid, and the concentration of the aniline solution is 25 mM; the dosage of ammonium persulfate is 25 mmol; the reaction time was 4 h.

A flexible conductive antibacterial material is prepared by the preparation method.

The flexible conductive antibacterial material can be used for tissue repair.

In the invention, PANI is used for constructing the intrinsic conductive antibacterial hydrogel. Polyaniline is an inexpensive biocompatible polymer having a conjugated pi-bond structure to provide electrical conductivity. After doping, the conductivity is obviously improved, and the doped polyaniline has higher positive charge. Therefore, the positively charged polyaniline is likely to be a promising antibacterial agent. However, the interaction between polyaniline and bacterial cells has not been elucidated. To solve this problem, the present invention uses gram-positive and gram-negative bacteria to evaluate the antibacterial activity of polyaniline, and reveals its mechanism by studying the interaction between polyaniline and the adhesion amphiphile (important cell wall component) associated with the surface of the target bacteria. The polyaniline coupled polymer dopant SHA is used for constructing the conductive hydrogel dressing, and ES is used for researching the potential of the conductive hydrogel dressing for treating intractable infection chronic wounds in vivo. In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the invention adopts PANI and SHA as base materials to prepare the material for the flexible bioelectronic device, the material has the conductivity similar to human tissue, good biocompatibility and antibacterial property, and can be used for preparing products such as flexible conductive dressing and the like;

2. the invention modifies HA molecular chain, introduces sulfonic acid group to form macromolecular dopant, and can form high-efficiency long-term doping of PANI. Because the molecular weight is large, the material is not easy to dissolve out, and the conductivity of the material can be maintained for a long time;

3. the invention enhances the electropositivity of the PANI by doping, so that the PANI has good antibacterial performance. The wound dressing with intrinsic antibacterial property is prepared by utilizing the antibacterial property of PANI, so that the use of antibacterial agents such as antibiotics and the like can be avoided, the production cost of the dressing is reduced, and bacterial drug resistance and other toxic and side effects caused by the use of antibiotics can also be avoided.

5. The preparation method of the material adopted by the invention is carried out in aqueous solution, organic solvent is not needed, the production process is green and environment-friendly, and meanwhile, organic solvent residue is avoided, thus being beneficial to expanding the application range;

6. the invention has cheap raw materials and simple synthesis path, can quickly prepare a large amount of conductive materials, and is beneficial to the mass production and commercial application of novel flexible bioelectronic devices.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a technical roadmap of the present invention

FIG. 2 shows the results of the conductivity test of the hydrogel;

FIG. 3 is a tensile curve (A) and rheological test results (B, C) for a hydrogel;

FIG. 4 shows the cytotoxicity results;

FIG. 5 shows the results of the antibacterial performance;

fig. 6 is a graph of the results of electrical stimulation to promote wound healing.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

The preferred embodiment of the invention provides a preparation method of OHA, which comprises the following specific steps:

dissolving 1g HA in 100ml water, 0.8g NaIO₄Dissolving in 30ml of water, HA solution and NaIO₄The solutions were mixed and stirred in the absence of light for 3h, and an equimolar amount of ethylene glycol was added to quench the unreacted NaIO₄. Stirring for 2h, and removing NaIO by dialysis₄And formaldehyde to obtain OHA having an oxidation level of 20%;

example 2

The preferred embodiment of the invention provides a preparation method of OHA, which comprises the following specific steps:

dissolving 1g HA in 100ml water, 0.8g NaIO₄Dissolving in 30ml of water, HA solution and NaIO₄The solutions were mixed and stirred in the absence of light for 5h, and an equimolar amount of ethylene glycol was added to quench the unreacted NaIO₄. Stirring for 2h, and removing NaIO by dialysis₄And formaldehyde to obtain OHA having an oxidation degree of 30%;

example 3

The preferred embodiment of the invention provides a preparation method of OHA, which comprises the following specific steps:

dissolving 1g HA in 100ml water, 0.8g NaIO₄Dissolving in 30ml of water, HA solution and NaIO₄The solution was stirred in the absence of light for 7h and the unreacted NaIO4 was quenched by the addition of an equimolar amount of ethylene glycol. Stirring for 2h, and removing NaIO by dialysis₄And formaldehyde to obtain OHA having an oxidation level of 40%;

example 4

Based on example 1, a preferred embodiment of the present invention provides a preparation method of SHA, which comprises the following steps:

preparing 1 wt% OHA solution, adding NaHSO 5 wt% of reaction system₃And reacting at 50 ℃ for 5 hours. Dialyzing to obtain a sulfonation degree ofSHA of 7%.

Example 5

Based on embodiment 2, a preferred embodiment of the present invention provides a preparation method of SHA, which comprises the following steps:

preparing 1 wt% OHA solution, adding NaHSO 5 wt% of reaction system₃And reacting at 50 ℃ for 5 hours. After dialysis, SHA with a sulfonation degree of 17% was obtained.

Example 6

Based on embodiment 3, a preferred embodiment of the present invention provides a preparation method of SHA, which comprises the following steps:

preparing 1 wt% OHA solution, adding NaHSO 5 wt% of reaction system₃And reacting at 50 ℃ for 5 hours. After dialysis, SHA with a sulfonation degree of 19% was obtained.

Example 7

On the basis of embodiment 4, a preferred embodiment of the present invention provides a method for preparing a flexible, electrically conductive and antibacterial hydrogel, which comprises the following specific steps:

SHA, acrylamide (SHA to acrylamide mass ratio 1:9) and a crosslinking agent (N, N' -methylenebisacrylamide, MBAA,0.15 wt%) were dissolved in water. Then, a thermal initiator (ammonium persulfate, 0.018g) and an accelerator (N, N, N ', N' -tetramethylethylenediamine, TEMED, 18. mu.L) were added, and the solution was poured into a glass mold (100 mm. times.100 mm. times.1 mm) to react at 40 ℃ for 4 hours, and annealed at room temperature for 12 hours to prepare a PS1 hydrogel.

The PS1 hydrogel was immersed in 50mL solution containing 1.0M HCl and 25mM aniline for 24h, followed by the addition of 25mmol APS. After 4h of reaction, the resulting hydrogel was designated as PSP 1 hydrogel.

Example 8

On the basis of embodiment 5, a preferred embodiment of the present invention provides a method for preparing a flexible, electrically conductive and antibacterial hydrogel, which comprises the following specific steps:

SHA, acrylamide (SHA to acrylamide mass ratio 1:9) and a crosslinking agent (N, N' -methylenebisacrylamide, MBAA,0.15 wt%) were dissolved in water. Then, a thermal initiator (ammonium persulfate, 0.018g) and an accelerator (N, N, N ', N' -tetramethylethylenediamine, TEMED, 18. mu.L) were added, and the solution was poured into a glass mold to react at 40 ℃ for 4 hours, and annealed at room temperature for 12 hours to prepare a PS2 hydrogel.

The PS2 hydrogel was immersed in 50mL solution containing 1.0M HCl and 25mM aniline for 24h, followed by the addition of 25mmol APS. After 4h of reaction, the resulting hydrogel was designated as a PSP 2 hydrogel.

Example 9

On the basis of embodiment 5, a preferred embodiment of the present invention provides a method for preparing a flexible, electrically conductive and antibacterial hydrogel, which comprises the following specific steps:

SHA, acrylamide (SHA to acrylamide mass ratio 1:9) and a crosslinking agent (N, N' -methylenebisacrylamide, MBAA,0.15 wt%) were dissolved in water. Then, a thermal initiator (ammonium persulfate, 0.018g) and an accelerator (N, N, N ', N' -tetramethylethylenediamine, TEMED, 18. mu.L) were added, and the solution was poured into a glass mold to react at 40 ℃ for 4 hours, and annealed at room temperature for 12 hours to prepare PS3 hydrogel.

The PS3 hydrogel was immersed in 50mL solution containing 1.0M HCl and 25mM aniline for 24h, followed by the addition of 25mmol APS. After 4h of reaction, the resulting hydrogel was designated as a PSP3 hydrogel.

Experimental example 1

The conductivity of the material prepared in example 9 was tested.

The conductivity of the flexible conductive antibacterial hydrogel prepared in the above example was tested by the four-probe method, and the results are shown in fig. 2. PANI was introduced into a Polyacrylamide (PAM) matrix hydrogel by in situ polymerization of aniline. In order to prevent a rapid decrease in PANI conductivity due to loss of small molecule dopants under weakly basic physiological conditions, SHA was incorporated into the hydrogel as a macromolecular dopant. The degree of doping determines the intrinsic conductivity. The PSP hydrogel (PSP3) prepared using SHA with a sulfonation degree of 19% exhibited the highest conductivity (fig. 2). The conductivity of the PSP hydrogel was about 40 times higher than that of the PS hydrogel (fig. 2). On the other hand, when SHA with different degrees of sulfonation were added to polyacrylamide, but without PANI added, the conductivity did not change significantly (fig. 2). On the other hand, it was demonstrated that the conductivity came primarily from PANI. The conductivity of the PSP hydrogel in the swollen and dried states was 1.05mS/cm and 1.20mS/cm, respectively, indicating that hydrogel swelling had no significant effect on conductivity.

Experimental example 2

The material prepared in example 9 was tested for mechanical properties.

Wound dressings need sufficient strength to maintain their integrity and protect the wound from further trauma in daily use. The introduction of PANI significantly improved the mechanical properties of the hydrogel. Compared to the PS hydrogel, the maximum tensile strength of the PSP hydrogel was increased by 300% and the elongation at break was increased by 115% (fig. 3A). Wound dressings are commonly used in dynamic mechanical environments due to daily activities. The PSP hydrogel also showed sufficient stability to dynamic stimuli as shown by the stable modulus when the frequency was changed from 0.1Hz to 100Hz (approximate frequency range for daily activities) (fig. 3B). The strain sweep test (fig. 3C) indicated that the PSP hydrogel could maintain the hydrogel state until the strain reached 179%. The results also demonstrate that PSP hydrogels have sufficient dynamic stability because the strain generated by normal activities on human skin is < 100%. Under frequency and strain sweep mode, the G' of the PSP hydrogel was significantly higher than the PS hydrogel, indicating that the introduced PANI promoted the dynamic mechanical properties of the hydrogel. PSP hydrogels have better mechanical properties due to the dynamic hydrogen bonds formed between the rigid structure of PANI and the PANI chains and between PANI and PAM for energy dissipation. In addition, the in situ polymerization of aniline introduces another network into the hydrogel matrix, and the interpenetrating network formed also imparts good flexibility and strength to the hydrogel.

Experimental example 3

The material prepared in example 9 was tested for cytotoxicity.

Mouse fibroblasts were cultured in Dulbecco's modified Eagles Medium (i.e., DMEM) supplemented with 10% fetal bovine serum, 100U/mL penicillin and 100. mu.g/mL streptomycin. The material was cut into disc-shaped samples (3.5 mm. times.2 mm) and then sterilized by autoclave. Each of the sterile specimens was immersed in 3mL of DMEM at 37 ℃ for 24h to prepare a hydrogel extract. Ten thousand fibroblasts were seeded into each well of a 96-well plate and pre-cultured in 200 μ L of fresh DMEM for 24h to achieve complete adhesion. The medium was replaced with hydrogel extract and the cells were cultured for another 24 hours. Cell viability was then determined by the CCK-8 kit. The cytotoxicity results are shown in fig. 4, and experiments show that the material of the invention has no cytotoxicity.

Experimental example 4

The materials prepared in example 9 were tested for antimicrobial properties.

After attachment, the bacteria grow and proliferate to form a biofilm, which promotes strong adhesion of bacteria and hinders penetration of antibacterial agents by producing extracellular polymers. Thus, biofilms are difficult to eradicate and result in a large fraction (60%) of chronic wound infections. FIG. 5 shows that the bacterial density was reduced by more than 3 orders of magnitude compared to the PS hydrogel when a Staphylococcus aureus (S.aureus) biofilm was treated with the PSP hydrogel prepared in example 9. When a staphylococcus epidermidis (s. epidermidis) biofilm was treated with the PSP hydrogel prepared in example 9, the bacterial density was reduced by 2 orders of magnitude compared to the PS hydrogel. The results show that the material prepared by the invention can obviously inhibit the formation of the biological membrane.

Experimental example 5

The material prepared in example 9 was tested for its promoting effect on chronic wound healing.

Four full-thickness skin excision wounds were created on the upper back of each diabetic rat. In the Control group, the wound was not covered with a dressing, whereas in the Hydrogel group, the wound was treated with the conductive material prepared according to the present invention. For ES groups, the wound was electrically stimulated using conventional electrodes, without the use of hydrogel materials. In the ES + Hydrogel group, wounds were treated by applying electrical stimulation through a conductive material covering the wound. All wounds were inoculated with staphylococcus aureus to cause infection.

On day 3, wounds in the Control and ES groups were suppurative. However, no pus was observed on the PSP Hydrogel-treated wounds (Hydrogel group), indicating that the PSP Hydrogel had good antibacterial activity in vivo. On day 14, the Control group remained unhealed, while eschar was present in the ES and Hydrogel groups. In the ES + Hydrogel group, the wound healed completely. The wound closure rates were quantified for the four groups as a function of wound area (fig. 6). On day 14, the ES + Hydrogel group had 21% higher wound closure than the Control group.

In addition to wound size measurements, healing was also assessed by histomorphology. The degree of re-epithelialization and granulation tissue formation of the wound was assessed by epithelial thickness and granulation tissue width. The ES and Hydrogel groups showed a higher degree of re-epithelialization than the Control group, with a 28% and 27% thickening of the epithelial layer, respectively. The ES + Hydrogel group formed a multilayered epithelial structure after 14 days, with an epithelial thickness similar to a healthy epidermis of intact skin. Furthermore, in the ES + Hydrogel group, epithelial cells and connective tissues are more regular.

Granulation tissue width reflects the level of regeneration of wound tissue, with lower values indicating more mature granulation tissue and a higher degree of conversion to fibrous tissue. At day 14, the granulation tissue widths of the ES and Hydrogel groups were 1.2. + -. 0.24 and 2.3. + -. 0.28mm, respectively, whereas in the ES + Hydrogel group, most of the wound area was filled with regenerated mature skin tissue and the granulation tissue width was only 1.2. + -. 0.52 mm.

Collagen deposition plays an important role in wound repair and maturation. The collagen deposition was higher in the other three groups compared to the Control group. For the ES and Hydrogel groups, the relative collagen deposition was 47% and 51%, respectively. Furthermore, the ES + Hydrogel group showed 61% relative collagen deposition, 2-fold higher than the Control group (31%), and also a high degree of directional alignment, indicating an improvement in extracellular matrix remodeling and tissue remodeling.

The above-mentioned embodiments only express the specific embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for those skilled in the art, without departing from the technical idea of the present application, several changes and modifications can be made, which are all within the protection scope of the present application.