Ultrasonic-responsive piezoelectric hydrogel and preparation method and application thereof

Abstract

The application relates to the technical field of surgical biomaterials, and discloses an ultrasonic-responsive piezoelectric hydrogel as well as a preparation method and application thereof.The ultrasonic-responsive piezoelectric hydrogel comprises a conductive hydrogel base body and gallium selenide nanosheets dispersed and loaded in the conductive hydrogel base body; and the conductive hydrogel base body is formed by cross-linking hyperbranched polyglycidol grafted with gamma-polyglutamic acid and polyvinyl alcohol through hydrogen bonding.Under ultrasonic excitation, the gallium selenide nanosheets convert mechanical energy into a microelectric field through a piezoelectric effect and synchronously catalyze hydrogen production from water / glucose, while releasing gallium ions, which synergistically play multiple therapeutic roles: the microelectric field promotes fibroblast proliferation, migration and vascular regeneration, hydrogen gas removes active oxygen in an oxidative stress environment and improves a diabetic wound microenvironment, and the gallium ions realize efficient antibacterial effect on methicillin-resistant Staphylococcus aureus by interfering with bacterial iron metabolism, thereby constructing a response-type treatment system integrating antibacterial effect, antioxidant effect and healing promotion.

Description

Technical Field

[0001] This invention relates to the field of surgical biomedical materials technology, and in particular to an ultrasound-responsive piezoelectric hydrogel, its preparation method, and its application. Background Technology

[0002] Diabetic chronic wounds, most typically manifested as diabetic foot ulcers, are a serious complication in diabetic patients with a high incidence, significant harm, and persistently high disability rate. Unlike ordinary acute wounds, the long-term high-sugar environment and metabolic abnormalities in patients lead to significantly delayed wound healing. The wound site exhibits persistent inflammatory responses, colonization of harmful bacteria forming biofilms, and slow proliferation and migration of fibroblasts, thus creating an irreversible closed vicious cycle of infection-oxidative stress-inflammation-tissue repair impairment, posing a great challenge to clinical treatment.

[0003] In the local microenvironment of diabetic wounds, high blood glucose levels lead to mitochondrial dysfunction and neutrophil dysfunction through multiple pathways, including the accumulation of advanced glycation end products (AGEs). This results in abnormally high levels of reactive oxygen species (ROS) at the wound site, directly damaging cell membranes and DNA. More importantly, it causes macrophages to continuously transform into a pro-inflammatory phenotype, leading to the continuous production of pro-inflammatory cytokines and a persistent inflammatory response, keeping the wound in an inflammatory stage for an extended period. Simultaneously, the deficient local immune surveillance function, necrotic tissue accumulation, and moist environment of diabetic wounds provide excellent conditions for bacterial colonization. Multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), readily and rapidly multiply, forming dense and impermeable bacterial biofilms on the wound surface. These biofilms significantly reduce the penetration efficiency of antibiotics, rendering conventional anti-infective treatments ineffective. The continuous release of toxins and inflammatory factors by bacteria further disrupts the wound healing microenvironment, exacerbating tissue necrosis and ulceration. Therefore, the ability to simultaneously and efficiently eliminate ROS, block persistent inflammation, eradicate drug-resistant bacterial biofilms, and promote cell proliferation and angiogenesis has become crucial for the successful healing of chronic diabetic wounds.

[0004] In recent years, wound dressing research and development has rapidly evolved from traditional passive physical covering to functional approaches that actively regulate the wound microenvironment and target pathological mechanisms. For wound infection, silver ion dressings are widely used due to their broad-spectrum bactericidal effects; however, silver ions have potential toxicity to mammalian cells, inhibiting fibroblast activity and affecting normal tissue repair, raising significant safety concerns for long-term use. To address high oxidative stress in wounds, nanozyme dressings and plant polyphenol-based antioxidant dressings have been developed, which can remove ROS and alleviate oxidative damage to some extent. However, single antioxidant strategies cannot address complex pathological issues such as infection, inflammation, and insufficient electrical signal transduction, resulting in limited therapeutic effects. The emergence of piezoelectric materials provides a new pathway for non-invasive regulation of the wound microenvironment. Gallium selenide (GaSe), a typical two-dimensional layered piezoelectric semiconductor, undergoes minute deformation under mechanical stimulation from human activity or external medical ultrasound, converting mechanical energy into electrical charge and electrochemical energy through the piezoelectric effect, and possessing the ability to catalyze water decomposition to produce hydrogen. Hydrogen has been extensively studied and proven to possess highly efficient and safe antioxidant, anti-inflammatory, and anti-apoptotic effects. It can directly remove excess ROS in the wound area, reverse the pro-inflammatory phenotype of macrophages, and promote the transition of the wound from the inflammatory phase to the proliferative phase. Meanwhile, the gallium ions released from the slow degradation of GaSe in the physiological environment can exert a potent antibacterial effect by interfering with bacterial iron metabolism pathways, while the released selenium ions can further remove ROS through single-electron or two-electron reduction pathways, achieving a synergistic antioxidant effect.

[0005] However, pure GaSe nanomaterials suffer from poor dispersibility, insufficient structural stability, and low piezoelectric output efficiency in physiological environments, making it difficult to continuously generate sufficiently strong electrochemical driving forces to achieve efficient and stable hydrogen production. More importantly, traditional piezoelectric composite materials are mostly prepared using simple physical blending methods. The charges generated on the GaSe surface are easily shielded and dissipated by surrounding aqueous solutions, biomolecules, and other media, making it impossible to construct a continuous and efficient conductive network. This results in extremely low energy utilization of the piezoelectric effect, making it impossible to form a stable and conductive micro-electric field on the wound surface, and thus failing to effectively promote cell migration, proliferation, and tissue regeneration. Summary of the Invention

[0006] This invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of this invention is to provide an ultrasound-responsive piezoelectric hydrogel. This hydrogel uses a biocompatible polyglycidyl-γ-polyglutamic acid / polyvinyl alcohol composite hydrogel as a three-dimensional carrier to load two-dimensional gallium selenide nanosheets exhibiting piezoelectric-ferroelectric effects. Under ultrasonic excitation, the gallium selenide nanosheets convert mechanical energy into a micro-electric field through the piezoelectric effect and simultaneously catalyze the production of hydrogen from water / glucose, while releasing gallium ions. This synergistic effect provides multiple therapeutic benefits: the micro-electric field promotes fibroblast proliferation and migration and angiogenesis; hydrogen gas removes reactive oxygen species from oxidative stress environments and improves the microenvironment of diabetic wounds; gallium ions achieve highly effective antibacterial activity against methicillin-resistant Staphylococcus aureus by interfering with bacterial iron metabolism; and the hydrogel itself, with its injectable, self-healing, and wound-adhering properties, constructs a responsive therapeutic system integrating antibacterial, antioxidant, and healing-promoting properties, addressing the core issues of chronic diabetic wound infection, oxidative stress imbalance, and delayed healing.

[0007] The second objective of this invention is to provide a method for preparing an ultrasonically responsive piezoelectric hydrogel.

[0008] The third objective of this invention is to provide a wound dressing.

[0009] The fourth objective of this invention is to provide an application for this wound dressing.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides an ultrasonically responsive piezoelectric hydrogel, comprising a conductive hydrogel matrix and gallium selenide nanosheets dispersed and loaded in the conductive hydrogel matrix; wherein the conductive hydrogel matrix is ​​formed by crosslinking hyperbranched polyglycidol grafted with γ-polyglutamic acid and polyvinyl alcohol through hydrogen bonding.

[0011] In some embodiments of the present invention, the cross-linked network of the conductive hydrogel matrix contains free carboxyl groups, forming an ionic conductive network.

[0012] In some embodiments of the present invention, the mass of the gallium selenide nanosheet is 0.25%-1.0% of the mass of the conductive hydrogel matrix.

[0013] In some preferred embodiments of the present invention, the mass of the gallium selenide nanosheet is 0.25%-0.5% of the mass of the conductive hydrogel matrix.

[0014] In some embodiments of the present invention, the gallium selenide nanosheets have a two-dimensional layered structure with an average particle size of 150-250 nm.

[0015] In some preferred embodiments of the present invention, the gallium selenide nanosheets have a two-dimensional layered structure with an average particle size of 180-220 nm.

[0016] A second aspect of the present invention provides a method for preparing the ultrasonically responsive piezoelectric hydrogel described in the first aspect of the present invention, comprising the following steps: Gallium selenide powder in bulk form was dispersed in solvent I and then ultrasonically exfoliated in an ice bath to obtain gallium selenide nanosheets. Polyglycidyl ether (HPG) was mixed with solvent II and then carboxylated with succinic anhydride to obtain carboxylated polyglycidyl ether (HPG-COOH). The carboxylated polyglycidol was mixed with an activating reagent and reacted to obtain activated carboxylated polyglycidol. The activated carboxyl polyglycidol was subjected to an amidation grafting reaction with γ-polyglutamic acid (PGA) to obtain hyperbranched polyglycidol grafted with γ-polyglutamic acid (HPG-PGA). The gallium selenide nanosheets, polyvinyl alcohol (PVA), and hyperbranched polyglycidol grafted with γ-polyglutamic acid were crosslinked in an aqueous solution to obtain the ultrasonically responsive piezoelectric hydrogel (HPG-PGA / PVA@GaSe). Solvent I includes N-methylpyrrolidone (NMP); solvent II includes pyridine.

[0017] In some embodiments of the present invention, the solid-liquid ratio of the bulk gallium selenide powder to solvent I is 1 mg:(0.8-1.2) mL.

[0018] In some preferred embodiments of the present invention, the solid-liquid ratio of the bulk gallium selenide powder to solvent I is 1 mg:(0.9-1.1) mL.

[0019] In some embodiments of the present invention, the conditions for the ice bath ultrasonic ablation include: using cyclic indirect ultrasound, with a power of 400-600W, working for 1-3 seconds, stopping for 2-4 seconds, and a total working time of 14-22 hours.

[0020] In some preferred embodiments of the present invention, the conditions for the ice bath ultrasonic ablation include: using cyclic indirect ultrasound, with a power of 450-550W, working for 1-2 seconds, stopping for 3-4 seconds, and a total working time of 16-20 hours.

[0021] In some embodiments of the present invention, after the ice bath ultrasonic exfoliation is completed, differential centrifugation is also performed to collect the precipitate, followed by washing and dispersion.

[0022] In some embodiments of the present invention, the differential centrifugation includes centrifuging at 2400-3600 rpm for 12-18 min at 3-5°C, and then taking the supernatant and centrifuging at 10500-15500 rpm for 12-18 min.

[0023] In some preferred embodiments of the present invention, the differential centrifugation includes centrifuging at 2700-3300 rpm for 14-16 min at 3.5-4.5°C, and then taking the supernatant and centrifuging at 11700-14300 rpm for 14-16 min.

[0024] In some embodiments of the present invention, the washing reagent includes anhydrous ethanol, and the washing is performed 2-3 times.

[0025] In some embodiments of the present invention, the dispersion includes dispersion in anhydrous ethanol to obtain a gallium selenide nanosheet ethanol dispersion.

[0026] In some embodiments of the present invention, the ratio of polyglycidyl ether, solvent II and succinic anhydride is 1g:(12-18)mL:(1.2-1.8)g.

[0027] In some preferred embodiments of the present invention, the ratio of polyglycidyl ether, solvent II and succinic anhydride is 1g: (14-16)mL: (1.4-1.6)g.

[0028] In some embodiments of the present invention, the temperature at which the polyglycidyl ether is mixed with solvent II is 48-72°C.

[0029] In some preferred embodiments of the present invention, the temperature at which the polyglycidyl ether is mixed with solvent II is 54-66°C.

[0030] In some embodiments of the present invention, the process of mixing the polyglycidol with solvent II is aided by stirring.

[0031] In some embodiments of the present invention, the carboxylation treatment is performed under an inert atmosphere.

[0032] In some embodiments of the present invention, the inert atmosphere includes argon.

[0033] In some embodiments of the present invention, the carboxylation treatment is performed at a temperature of 48-72°C for 8-12 hours.

[0034] In some preferred embodiments of the present invention, the carboxylation treatment is performed at a temperature of 54-66°C for a time of 10-12 hours.

[0035] In some embodiments of the present invention, after the carboxylation treatment is completed, the process further includes dialysis to remove impurities and freeze-drying to remove water, in order to obtain the carboxylated polyglycidyl glycerol.

[0036] In some embodiments of the present invention, the activating agent comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS); the mass ratio of the carboxylated polyglycidyl, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide is 1: (86-130): (78-118).

[0037] In some preferred embodiments of the present invention, the activating agent comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide; the mass ratio of the carboxylated polyglycidyl, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide is 1: (97-119): (88-108).

[0038] In some embodiments of the present invention, the reaction is carried out at a pH of 4-5, a temperature of 20-30°C, and a time of 1-3 hours.

[0039] In some preferred embodiments of the present invention, the reaction is carried out at a pH of 4-5, a temperature of 20-25°C, and a time of 1.5-2.5 h.

[0040] In some embodiments of the present invention, the molecular weight of the γ-polyglutamic acid is 8000-12000 Da; the mass ratio of the carboxylated polyglycidol to the γ-polyglutamic acid is (3-5):1.

[0041] In some preferred embodiments of the present invention, the molecular weight of the γ-polyglutamic acid is 9000-11000 Da; the mass ratio of the carboxylated polyglycidol to the γ-polyglutamic acid is (3.5-4.5):1.

[0042] In some embodiments of the present invention, the amidation grafting reaction is performed at a pH of 6-8, a temperature of 20-30°C, and a time of 3-5 hours.

[0043] In some preferred embodiments of the present invention, the amidation grafting reaction is carried out at a pH of 6.5-7.5, a temperature of 20-25°C, and a time of 3.5-4.5 h.

[0044] In some embodiments of the present invention, after the amidation grafting reaction is completed, the process further includes repeated dialysis and freeze-drying to obtain the hyperbranched polyglycidol grafted with γ-polyglutamic acid.

[0045] In some embodiments of the present invention, the crosslinking reaction of the gallium selenide nanosheets, polyvinyl alcohol, and the hyperbranched polyglycidol grafted with γ-polyglutamic acid in an aqueous solution specifically includes: The gallium selenide nanosheet ethanol dispersion was centrifuged to collect the precipitate and dispersed in water to form an aqueous dispersion of gallium selenide nanosheets. Polyvinyl alcohol is dissolved in water to form a polyvinyl alcohol aqueous solution; Hyperbranched polyglycidol grafted with γ-polyglutamic acid was dissolved in water to form an aqueous solution of hyperbranched polyglycidol grafted with γ-polyglutamic acid. Gallium selenide nanosheet aqueous dispersion was mixed with polyvinyl alcohol aqueous solution, and then hyperbranched polyglycidol aqueous solution grafted with γ-polyglutamic acid was added. The mixture was then vortexed and crosslinked to obtain the ultrasonically responsive piezoelectric hydrogel.

[0046] In some embodiments of the present invention, the concentration of the gallium selenide nanosheet aqueous dispersion is 16-24 mg / mL.

[0047] In some preferred embodiments of the present invention, the concentration of the gallium selenide nanosheet aqueous dispersion is 18-22 mg / mL.

[0048] In some embodiments of the present invention, the centrifugation temperature is 3-5°C, the rotation speed is 10500-15500 rpm, and the time is 12-18 min.

[0049] In some preferred embodiments of the present invention, the centrifugation temperature is 3.5-4.5℃, the rotation speed is 2700-3300rpm, and the time is 14-16min.

[0050] In some embodiments of the present invention, the concentration of the polyvinyl alcohol aqueous solution is 8wt%-12wt%.

[0051] In some preferred embodiments of the present invention, the concentration of the polyvinyl alcohol aqueous solution is 9wt%-11wt%.

[0052] In some embodiments of the present invention, the concentration of the hyperbranched polyglycidol aqueous solution grafted with γ-polyglutamic acid is 16wt%-24wt%.

[0053] In some preferred embodiments of the present invention, the concentration of the hyperbranched polyglycidol aqueous solution grafted with γ-polyglutamic acid is 18wt%-22wt%.

[0054] In some embodiments of the present invention, the mass ratio of the gallium selenide nanosheets, polyvinyl alcohol and the hyperbranched polyglycidol grafted with γ-polyglutamic acid is 1: (18-27): (12-18).

[0055] In some preferred embodiments of the present invention, the mass ratio of the gallium selenide nanosheets, polyvinyl alcohol and the hyperbranched polyglycidol grafted with γ-polyglutamic acid is 1: (20-25): (14-16).

[0056] A third aspect of the present invention provides a wound dressing comprising the ultrasound-responsive piezoelectric hydrogel described in the first aspect of the present invention.

[0057] The fourth aspect of the present invention provides the application of the wound dressing described in the third aspect of the present invention in the repair of diabetic infected wounds.

[0058] In some embodiments of the present invention, the wound dressing, under medical ultrasound stimulation, catalyzes hydrogen production, scavenges reactive oxygen species, and exhibits antibacterial, anti-inflammatory, and wound-healing effects through the ultrasound-responsive piezoelectric hydrogel.

[0059] In some embodiments of the present invention, the ultrasonically responsive piezoelectric hydrogel has an antibacterial rate of greater than 99% against methicillin-resistant Staphylococcus aureus.

[0060] In some embodiments of the present invention, the ultrasonically responsive piezoelectric hydrogel has a hydrogen generation rate of 0.06-0.2 μmol / L / min under medical ultrasonic stimulation.

[0061] Compared with the prior art, the beneficial effects of the present invention are: The ultrasonically responsive piezoelectric hydrogel provided by this invention utilizes gallium selenide nanosheets to catalyze water decomposition to generate hydrogen gas under medical ultrasound excitation, while simultaneously consuming glucose accumulated in the wound and improving the microenvironment of high glucose metabolism. Hydrogen gas, as a potent antioxidant, can scavenge excess reactive oxygen species, alleviating oxidative stress. The synergistically released gallium ions exhibit an antibacterial rate of >99% against methicillin-resistant Staphylococcus aureus, and selenium ions further assist in neutralizing free radicals. The conductive hydrogel matrix absorbs ions from wound exudate to form a highly efficient conductive network, transmitting the microcurrent generated by piezoelectricity to the entire wound surface, promoting fibroblast proliferation, migration, and angiogenesis. This hydrogel possesses self-healing and shear-thinning properties, allowing it to be injected and adhere to irregular wounds. It breaks the vicious cycle of infection, oxidative stress, and healing barriers in diabetic wounds from multiple dimensions—antibacterial, antioxidant, and healing-promoting—providing an integrated solution for chronic wound treatment. Attached Figure Description

[0062] Figure 1 The image shown is a TEM image of gallium selenide nanosheets in the example. Figure 2 The hydrated particle size distribution and polydispersity index of gallium selenide nanosheets in the examples are shown. Figure 3 The butterfly curve (a) and hysteresis loop (b) of gallium selenide nanosheets in the examples are shown. Figure 4 The examples show the hydrogen production curve (a) and glucose consumption curve (b) of gallium selenide nanosheets under ultrasonic excitation. Figure 5 The results of the cytotoxicity test of gallium selenide nanosheets on mouse (a) and human (b) skin fibroblasts in the examples are shown. Figure 6 The image shows the gelation state of the ultrasonically responsive piezoelectric hydrogel in the example. Figure 7 The diagram shows the bending performance test results of the ultrasonically responsive piezoelectric hydrogel in this embodiment. Figure 8 The rheological properties (a) and self-healing properties (b) of the ultrasonically responsive piezoelectric hydrogel in the examples are shown. Figure 9 This demonstrates the free radical scavenging effect of gallium selenide nanosheets in the embodiments; Figure 10 Flow cytometry (a) and quantitative fluorescence chromatogram (b) showing the effect of oxidative stress relief on L929 mouse fibroblasts; Figure 11 The conductivity test results of the ultrasonically responsive piezoelectric hydrogel in the examples are shown. Figure 12 For electrical signal output of different processing groups; Figure 13 The electrical signal output of the ultrasonically responsive piezoelectric hydrogel under different ultrasonic powers in the examples; Figure 14 The following are the evaluation results (a) and colony count quantification diagram (b) of the antibacterial effect of the ultrasonic-responsive piezoelectric hydrogel plate coating in the examples; Figure 15 Results of the scratch healing experiment on L929 cells; Figure 16 This is a quantitative graph of the healing area in a scratch healing experiment. Detailed Implementation

[0063] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments can be obtained from conventional commercial sources or by existing technical methods. Unless otherwise specified, the experimental or testing methods are conventional methods in the art.

[0064] Example This embodiment prepares an ultrasonically responsive piezoelectric hydrogel, and the steps are as follows: S1. Weigh out lumpy GaSe powder and disperse it in N-methylpyrrolidone at a concentration of 1 mg / mL. The resulting dispersion is then subjected to ultrasonic exfoliation under ice bath conditions using a cyclic indirect ultrasonic mode at a power of 500 W, with a working time of 2 seconds and a stop time of 3 seconds, for a total effective ultrasonic time of 18 h. The resulting nanosheet dispersion is then subjected to differential centrifugation. First, centrifuge at 3000 rpm for 15 min at 4 °C, collect the supernatant, and then centrifuge at 13000 rpm for 15 min to collect the precipitate. The obtained nanosheet precipitate is dispersed in anhydrous ethanol, washed twice, and stored in anhydrous ethanol to obtain a gallium selenide nanosheet ethanol dispersion. S2. Weigh 1g of polyglycidyl ether and add it to 15mL of pyridine. Stir at 60℃ until completely dissolved, then add 1.5g of succinic anhydride. Maintain the reaction at 60℃ overnight under argon protection. After the reaction is complete, dialyze to remove impurities, freeze dry to remove water, and obtain carboxylated polyglycidyl ether (HPG-COOH). S3. Weigh 1g of carboxylated polyglycidyl, adjust the pH to between 4 and 5, add 108mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 98.5mg of N-hydroxysuccinimide, react at room temperature for 2h to obtain activated carboxylated polyglycidyl. S4. Add 250 mg of γ-polyglutamic acid with a molecular weight of 10000 Da to activated carboxyl polyglycidol, adjust the pH to 7, and react at room temperature for 4 h; the product after reaction is repeatedly dialyzed and freeze-dried to obtain hyperbranched polyglycidol grafted with γ-polyglutamic acid (HPG-PGA). S5. Take 4 mL of 1 mg / mL gallium selenide nanosheet ethanol dispersion, centrifuge at 13000 rpm for 15 min at 4℃, collect the precipitate, add 200 μL of water and re-disperse ultrasonically to form an aqueous dispersion of gallium selenide nanosheets; weigh 2 g of polyvinyl alcohol powder, add it to 20 mL of deionized water, and sterilize at high temperature and high pressure to obtain a 10 wt% polyvinyl alcohol aqueous solution; weigh 0.5 g of hyperbranched polyglycidol grafted with γ-polyglutamic acid and dissolve it in 2.5 mL of water to obtain a 20 wt% aqueous solution of hyperbranched polyglycidol grafted with γ-polyglutamic acid; add 0.9 g of polyvinyl alcohol aqueous solution to the aqueous dispersion of gallium selenide nanosheets, mix well, then add 0.3 g of hyperbranched polyglycidol grafted with γ-polyglutamic acid, and vortex crosslink to obtain an ultrasonically responsive piezoelectric hydrogel, denoted as HPG-PGA / PVA@GaSe.

[0065] Characterization and performance testing 1. The morphology and size of gallium selenide nanosheets in the examples were observed using transmission electron microscopy, and the hydration particle size and polydispersity index (PDI) of the gallium selenide nanosheets were measured using dynamic light scattering. Figure 1 The image shown is a TEM image of gallium selenide nanosheets in the examples. Figure 1It can be seen that the gallium selenide layers prepared by ultrasonic exfoliation are fewer, and the resulting two-dimensional layered nanosheets have a uniform morphology and no obvious agglomeration. Figure 2 The hydrated particle size distribution and polydispersity index of gallium selenide nanosheets in the examples are shown below. Figure 2 It can be seen that gallium selenide nanosheets have good dispersibility in aqueous solution, moderate hydrated particle size, average particle size of about 200 nm, and low polydispersity index (0.2330), indicating that the nanosheets have uniform size and high stability.

[0066] 2. The gallium selenide nanosheets in the examples were characterized using piezoelectric microscopy (PFM) to obtain butterfly curves (amplitude-voltage curves) and hysteresis loops (phase-voltage curves): Figure 3 The butterfly curve (a) and hysteresis loop (b) of the gallium selenide nanosheets in the examples are shown below. Figure 3 As can be seen, piezoelectric microscopy shows that gallium selenide nanosheets have uniform thickness and complete two-dimensional structure. The butterfly curve is a typical piezoelectric response curve, indicating that it has significant electro-strain characteristics. The hysteresis loop shows a 180° phase reversal, proving that gallium selenide nanosheets have ferroelectricity and strong piezoelectric activity, and can generate a stable piezoelectric field under mechanical stimulation.

[0067] 3. Performance test of gallium selenide nanosheets in hydrogen production and glucose consumption in the embodiments: Gallium selenide nanosheets were dispersed in 4 mL of glucose solution, loaded into a sealed vial, and the solution was sonicated using a medical ultrasonic physiotherapy instrument. The ultrasonic parameters included: 1 MHz, 50% duty cycle, and power of 1 W / cm². 2 1.5W / cm 2 and 2W / cm 2 The cumulative hydrogen gas content was measured every 5 minutes using a gas chromatograph, while the glucose consumption was determined using a glucose assay kit, and the measurements were taken for 30 minutes. Figure 4 The figures (a) and (b) show the hydrogen production curves and glucose consumption curves of gallium selenide nanosheets under ultrasonic excitation in the examples. ,Depend on Figure 4 It was found that under ultrasonic excitation, the amount of hydrogen produced by gallium selenide nanosheets catalyzing water splitting increased significantly with increasing ultrasonic time and ultrasonic power, with a hydrogen production rate reaching 0.06-0.2 μmol / min. Simultaneously, gallium selenide nanosheets can simultaneously consume glucose during piezoelectric catalysis, and the glucose consumption rate is positively correlated with the ultrasonic power.

[0068] 4. Cytotoxicity test of gallium selenide nanosheets in the examples: The toxicity of gallium selenide nanosheets to mouse skin fibroblasts and human skin fibroblasts in the examples was detected by the CCK-8 assay. The concentration of gallium selenide nanosheets was 0-30 μg / mL. Figure 5The results of the cytotoxicity test of gallium selenide nanosheets on mouse (a) and human (b) skin fibroblasts in the examples are presented by... Figure 5 It can be seen that gallium selenide nanosheets have no obvious cytotoxicity in the range of 0-30 μg / mL, and the survival rate of mouse and human skin fibroblasts is greater than 90%, indicating that they have excellent biocompatibility.

[0069] 5. The gelation state of the ultrasonically responsive piezoelectric hydrogel in the embodiments was observed through tube rotation experiments. Its storage modulus (G') and loss modulus (G'') were tested using a rheometer to evaluate its viscoelasticity and mechanical strength, and its self-healing and bendability were observed. Figure 6 This is a diagram showing the gelation state of the ultrasonically responsive piezoelectric hydrogel in the examples. Figure 6 It is known that hyperbranched polyglycidol (HPG-PGA) grafted with γ-polyglutamic acid can be rapidly molded at room temperature and does not flow when inverted, forming a stable hydrogel (HPG-PGA / PVA@GaSe) after being mixed with gallium selenide nanosheets and polyvinyl alcohol aqueous solution (PVA+GaSe).

[0070] Figure 7 The diagram shows the bending performance test results of the ultrasonically responsive piezoelectric hydrogel in this embodiment. Figure 7 As can be seen, the ultrasonic responsive piezoelectric hydrogel in the embodiment has good flexibility and can adhere well under bending at 30°, 60° and even 90°, indicating that the ultrasonic responsive piezoelectric hydrogel provided by the present invention can adhere tightly to irregular wound surfaces.

[0071] Figure 8 The rheological properties (a) and self-healing properties (b) of the ultrasonically responsive piezoelectric hydrogel in the examples are test results from... Figure 8 It can be seen that within the low strain range (0-1%), the storage modulus G' of the ultrasonic responsive piezoelectric hydrogel is significantly higher than the loss modulus G'', exhibiting stable elastic gel behavior. When the strain exceeds the critical value (>1%), G' rapidly decreases and falls below G'', exhibiting typical shear thinning characteristics. Under high strain (100%), the modulus of the ultrasonic responsive piezoelectric hydrogel decreases significantly and exhibits fluid characteristics. When the strain recovers to a low strain (0.1%), G' can rapidly recover and return to the initial level, demonstrating excellent mechanical responsiveness and self-healing ability. Moreover, the modulus does not significantly decrease after multiple cycles, proving that the ultrasonic responsive piezoelectric hydrogel has good dynamic structural reversibility.

[0072] 6. In vitro antioxidant performance tests of gallium selenide nanosheets and ultrasonically responsive piezoelectric hydrogels in the examples: 2,2'-Azide-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging: Prepare 7.4 mmol / L ABTS solution and 2.6 mmol / L potassium persulfate solution separately with distilled water, mix them thoroughly at a 1:1 (v / v) ratio, and let them stand at room temperature in the dark for 12-16 hours. Before use, dilute the solution 50-60 times with anhydrous ethanol until the absorbance measured by UV spectrophotometer is around 0.7, at which point the ABTS working solution is obtained. Add 1 mL of ABTS working solution to different centrifuge tubes, then add gallium selenide nanosheet aqueous dispersion in sequence, mix in the dark for 10 min, and then measure the absorbance value A at a wavelength of 734 nm. x Replace the gallium selenide nanosheet aqueous dispersion with an equal volume of distilled water, repeat the above operation, and measure the absorbance value A0. Calculate the absorbance using the formula: ABTS free radical scavenging activity (%) = (A0 - A x ) / A0×100% Calculation of the scavenging effect of gallium selenide nanosheet aqueous dispersion on ABTS free radicals: Cellular ROS detection: Different treatment groups were set up: control group, H2O2 treatment group, gallium selenide nanosheet treatment group, gallium selenide nanosheet + ultrasound treatment group (Gase + US), ultrasound-responsive piezoelectric hydrogel treatment group (HPG-PGA / PVA@GaSe), and ultrasound-responsive piezoelectric hydrogel + ultrasound treatment group (HPG-PGA / PVA@GaSe + US); L929 mouse fibroblasts in logarithmic growth phase were harvested, and after adjusting the cell density, they were seeded into culture plates, except... In addition to the control group, each of the other treatment groups was given an appropriate final concentration of H2O2 to construct an in vitro oxidative stress injury model. After group treatment, the intracellular reactive oxygen species (ROS) level was detected by DCFH-DA fluorescent probe method combined with flow cytometry. DCFH-DA itself is non-fluorescent and can freely penetrate the cell membrane. After entering the cell, it is hydrolyzed by intracellular esterases to generate non-membrane-permeable DCFH. Intracellular ROS can oxidize non-fluorescent DCFH to generate strongly fluorescent DCF. By detecting the intensity of green fluorescence, the level of intracellular ROS can be directly reflected.

[0073] Figure 9 To illustrate the free radical scavenging effect of gallium selenide nanosheets in the examples, [the following text is incomplete and requires further context: "by..."] Figure 9 It is known that gallium selenide nanosheets can effectively scavenge ABTS free radicals, with a scavenging rate of up to 60% at a concentration of 15 μg / mL.

[0074] Figure 10 Flow cytometry (a) and quantitative PCR results (b) show the effects of these methods on oxidative stress relief in L929 mouse fibroblasts. Figure 10It can be seen that the ROS level in the H2O2 treatment group was significantly increased, while gallium selenide nanosheets and ultrasound-responsive piezoelectric hydrogels could reduce intracellular ROS to normal levels under ultrasound, significantly alleviating oxidative stress damage, indicating that both have excellent in vitro antioxidant capacity.

[0075] 7. Different treatment groups were set up: polyvinyl alcohol (PVA) treatment group, conductive hydrogel matrix treatment group (HPG-PGA / PVA), polyvinyl alcohol + water treatment group (PVA + H2O), conductive hydrogel matrix + water treatment group (HPG-PGA / PVA + H2O), polyvinyl alcohol + Durham's phosphate buffer treatment group (PVA + DPBS), and conductive hydrogel matrix + Durham's phosphate buffer treatment group (HPG-PGA / PVA + DPBS). The conductivity of different materials was tested using an electrochemical workstation, and the ultrasonic responsive piezoelectric hydrogels in the examples were tested at different ultrasonic powers (0, 0.5, 1, 1.5, and 2 W / cm²). 2 Electrical signal output under the following conditions: The conductive hydrogel matrix is ​​prepared as follows: 2g of polyvinyl alcohol powder is weighed and added to 20mL of deionized water. After high-temperature and high-pressure sterilization, a 10wt% polyvinyl alcohol aqueous solution is obtained. 0.5g of hyperbranched polyglycidol grafted with γ-polyglutamic acid is weighed and dissolved in 2.5mL of water to obtain a 20wt% hyperbranched polyglycidol grafted with γ-polyglutamic acid aqueous solution. 0.9g of the polyvinyl alcohol aqueous solution and 0.3g of the hyperbranched polyglycidol grafted with γ-polyglutamic acid aqueous solution are mixed and vortex crosslinked to obtain the conductive hydrogel matrix.

[0076] Figure 11 The conductivity test results of the ultrasonically responsive piezoelectric hydrogel in the examples are from... Figure 11 It can be seen that the conductivity of ultrasonically responsive piezoelectric hydrogels is significantly improved in the presence of exudate ions due to the formation of ionic conductive pathways by a large number of free carboxyl groups.

[0077] Figure 12 For electrical signal output of different processing groups, Figure 13 To illustrate the electrical signal output of the ultrasonically responsive piezoelectric hydrogel under different ultrasonic powers in this embodiment, [the signal is generated by...]. Figure 12 and Figure 13 It can be seen that the ultrasonic responsive piezoelectric hydrogel outputs a stable electrical signal under ultrasonic stimulation, and the signal intensity increases with the increase of ultrasonic power, while the control group without gallium selenide nanosheets has no obvious electrical signal output.

[0078] 8. Antibacterial performance test of the ultrasonically responsive piezoelectric hydrogel in the examples: Different treatment groups were set up: control group, conductive hydrogel matrix treatment group (HPG-PGA / PVA), gallium selenide nanosheet treatment group (32 μg / mL GaSe), and ultrasonically responsive piezoelectric hydrogel treatment group (HPG-PGA / PVA@GaSe). The antibacterial effect of different materials on methicillin-resistant Staphylococcus aureus (MRSA) was evaluated using the plate count method. MRSA bacterial suspensions in the logarithmic growth phase were diluted to 1×10⁻⁶. 6 CFU / mL, 1 mL was inoculated into a 24-well plate, and different materials were added to each well. All groups were co-cultured in a 37℃ incubator. After the culture was completed, the bacterial solution of each well was collected and serially diluted. The bacterial solution of the appropriate dilution was evenly spread on LB agar plates and incubated at 37℃ for 12 h. After colony counting, the antibacterial rate of each group of materials was calculated based on the colony forming units, and its antibacterial efficiency was evaluated.

[0079] Figure 14 The images show the evaluation results (a) and colony count quantification (b) of the antibacterial effect of the ultrasonically responsive piezoelectric hydrogel plate coating in the examples. ,Depend on Figure 14 It can be seen that the conductive hydrogel matrix has no antibacterial effect, while the gallium selenide nanosheets and the ultrasonically responsive piezoelectric hydrogel both have an antibacterial rate of >99% against MRSA, and have a very significant bactericidal effect.

[0080] 9. Different treatment groups were set up: control group, control group + ultrasound (Control + US), gallium selenide nanosheet treatment group (GaSe), gallium selenide nanosheet + ultrasound treatment group (GaSe + US), conductive hydrogel matrix treatment group (HPG-PGA / PVA), conductive hydrogel matrix + ultrasound treatment group (HPG-PGA / PVA + US), ultrasound-responsive piezoelectric hydrogel treatment group (HPG-PGA / PVA@GaSe), and ultrasound-responsive piezoelectric hydrogel + ultrasound treatment group (HPG-PGA / PVA@GaSe + US). Scratch assays were performed using L929 mouse fibroblasts to detect the effect of each material on cell migration. Figure 15 The results of the L929 cell scratch healing experiment are as follows. Figure 16 This is a quantitative graph of the healing area in a scratch healing experiment, where... ,Depend on Figure 15 and Figure 16 As can be seen, compared with the control group, the ultrasound-responsive piezoelectric hydrogel in this example can significantly promote the migration and proliferation of fibroblasts under the action of ultrasound, significantly increase the scratch healing area, and accelerate the tissue repair process, proving that the piezoelectric microfield can effectively promote wound repair.

Claims

1. An ultrasonically responsive piezoelectric hydrogel, characterized in that, The invention includes a conductive hydrogel matrix and gallium selenide nanosheets dispersed and loaded in the conductive hydrogel matrix; wherein the conductive hydrogel matrix is ​​formed by cross-linking hyperbranched polyglycidol grafted with γ-polyglutamic acid and polyvinyl alcohol through hydrogen bonding.

2. The ultrasonically responsive piezoelectric hydrogel according to claim 1, characterized in that, The mass of the gallium selenide nanosheets is 0.25%-1.0% of the mass of the conductive hydrogel matrix.

3. The ultrasonically responsive piezoelectric hydrogel according to claim 2, characterized in that, The gallium selenide nanosheets have a two-dimensional layered structure with an average particle size of 150-250 nm.

4. A method for preparing the ultrasonically responsive piezoelectric hydrogel according to any one of claims 1-3, characterized in that, Includes the following steps: Gallium selenide powder in bulk form was dispersed in solvent I and then ultrasonically exfoliated in an ice bath to obtain gallium selenide nanosheets. Polyglycidol was mixed with solvent II and then subjected to succinic anhydride carboxylation to obtain carboxylated polyglycidol. The carboxylated polyglycidol was mixed with an activating reagent and reacted to obtain activated carboxylated polyglycidol. The activated carboxyl polyglycidol was subjected to an amidation grafting reaction with γ-polyglutamic acid to obtain hyperbranched polyglycidol grafted with γ-polyglutamic acid. The gallium selenide nanosheets, polyvinyl alcohol and hyperbranched polyglycidyl grafted with γ-polyglutamic acid were cross-linked in an aqueous solution to obtain the ultrasonically responsive piezoelectric hydrogel. Solvent I includes N-methylpyrrolidone; solvent II includes pyridine.

5. The preparation method according to claim 4, characterized in that, The solid-liquid ratio of the bulk gallium selenide powder to solvent I is 1 mg: (0.8-1.2) mL; And / or, the conditions for the ice bath ultrasonic ablation include: using cyclic indirect ultrasound, with a power of 400-600W, working for 1-3 seconds, stopping for 2-4 seconds, and a total working time of 14-22 hours.

6. The preparation method according to claim 4, characterized in that, The ratio of polyglycidyl ether, solvent II, and succinic anhydride is 1g: (12-18)mL: (1.2-1.8)g; And / or, the carboxylation treatment is performed at a temperature of 48-72°C for 8-12 hours.

7. The preparation method according to claim 4, characterized in that, The activating agent comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide; the mass ratio of the carboxylated polyglycidyl glycerol, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide is 1: (86-130): (78-118); And / or, the reaction is carried out at a pH of 4-5, a temperature of 20-30°C, and a time of 1-3 hours.

8. The preparation method according to claim 4, characterized in that, The molecular weight of the γ-polyglutamic acid is 8000-12000 Da; the mass ratio of the carboxylated polyglycidol to the γ-polyglutamic acid is (3-5): 1; And / or, the amidation grafting reaction is performed at a pH of 6-8, a temperature of 20-30°C, and a time of 3-5 hours.

9. A wound dressing, characterized in that, Includes the ultrasonically responsive piezoelectric hydrogel according to any one of claims 1-3.

10. The application of the wound dressing according to claim 9 in the repair of diabetic infected wounds.

Images