Energy-responsive multi-catalytic nanogenerator hydrogel and preparation and application thereof

Abstract

The application discloses an energy response type multi-catalytic nanogenerator hydrogel and a preparation and application thereof. The method comprises the following steps: synthesizing a tetragonal phase barium titanate nanocube through a hydrothermal method, preparing a gold-palladium / barium titanate nanocomposite material through a piezoelectric driving in-situ reduction strategy, and finally dispersing the nanocomposite material in a temperature-sensitive Pluronic F127 matrix to prepare an injectable nanogenerator hydrogel. The hydrogel is designed based on clinical transcriptomics targets, has dual functions of cascade nanozyme catalysis and ultrasound response piezoelectric power generation, can simultaneously block an AGEs / RAGE inflammatory cascade reaction and compensate a mechanical sensing defect mediated by PIEZO2, effectively reprograms a diabetic microenvironment, promotes macrophage M2 polarization, angiogenesis and tendon-bone interface gradient tissue regeneration, significantly improves the structural integrity and mechanical strength of a diabetic rotator cuff injury repair, and has a controllable preparation process, good biocompatibility and a wide clinical transformation prospect.

Description

Technical Field

[0001] This invention belongs to the field of biomedical functional materials and tissue engineering technology, specifically relating to an energy-responsive multi-catalytic nanogenerator hydrogel, its preparation method, and its application. Background Technology

[0002] Rotator cuff tears (RCTs) are a common orthopedic condition with a high re-tear rate, especially in patients with type 2 diabetes, where the risk of repair failure is significantly increased. The high-glucose microenvironment in diabetes induces excessive reactive oxygen species (ROS) accumulation, driving the massive production of advanced glycation end products (AGEs) and activating their receptor RAGE signaling axis, forming an oxidative stress self-expansion cycle. This causes macrophages to remain locked in a pro-inflammatory M1 phenotype, while simultaneously inhibiting bone / tendon cell recruitment, ultimately leading to regeneration arrest at the tendon-bone interface (TBI). Current clinical treatments primarily rely on mechanical fixation, which cannot address the inherent biological defects of the tendon-bone interface in diabetes. Exogenous growth factor therapies suffer from poor stability, rapid degradation, and high costs. Cell therapy faces bottlenecks such as low cell survival and limited efficacy in the high-glucose oxidative stress microenvironment. More critically, current approaches fail to address the mechanotransmission dysfunction caused by the significant downregulation of the mechanosensitive hub gene PIEZO2 in the tendon-bone tissue of diabetic patients, thus failing to simultaneously repair the two core pathological disorders: metabolic-redox imbalance and bioelectromechanical sensing defects. While there are reports on the use of piezoelectric materials or antioxidant nanozymes for tissue repair, there is currently no nanogenerator hydrogel system designed based on clinical transcriptomics targets that can simultaneously achieve "metabolic-electrical signal dual regulation" to specifically address the clinical challenges of tendon-bone healing in diabetic rotator cuff injuries. Therefore, developing a multifunctional biomaterial that is pathologically matched, can precisely respond to physiological stimuli, and simultaneously regulates the inflammatory microenvironment and mechanosensory pathways is of great significance for improving the clinical efficacy of rotator cuff repair in diabetic patients. Summary of the Invention

[0003] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing an energy-responsive multi-catalytic nanogenerator hydrogel. This method, based on clinical transcriptomics target design, offers controllable and reproducible processes, and the prepared material can simultaneously achieve the synergistic effect of cascaded nanozyme catalysis and ultrasound-responsive piezoelectric power generation.

[0004] Another object of the present invention is to provide an energy-responsive multi-catalytic nanogenerator hydrogel prepared by the above preparation method.

[0005] Another objective of this invention is to provide the application of the above-mentioned energy-responsive multi-catalytic nanogenerator hydrogel in the preparation of materials for regulating the microenvironment of chronic inflammation, ultrasound-responsive electrostimulation biomaterials, materials for repairing diabetic rotator cuff injuries, and tissue engineering scaffolds for tendon and bone healing.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an energy-responsive multi-catalytic nanogenerator hydrogel, comprising the following steps:

[0008] Tetragonal barium titanate (BTO) nanocrystals were synthesized using a hydrothermal method. Subsequently, a gold-palladium bimetallic alloy was loaded onto the surface of the BTO nanocrystals using a piezoelectric-driven in-situ reduction strategy to obtain a gold-palladium / barium titanate (Au-Pd / BTO, abbreviated as APB) nanocomposite material. Finally, the gold-palladium / barium titanate nanocomposite material was dispersed in a thermosensitive hydrogel matrix to form a gel, resulting in an energy-responsive multi-catalytic nanogenerator hydrogel (abbreviated as APBF hydrogel).

[0009] Preferably, the preparation method of the energy-responsive multi-catalytic nanogenerator hydrogel includes the following steps:

[0010] (1) Preparation of tetragonal barium titanate (BTO) nanocrystals:

[0011] Titanium source solution was added dropwise to barium source solution, surfactant was added, the pH of the system was adjusted to alkaline, hydrothermal reaction was carried out, centrifuged, washed, and dried to obtain tetragonal barium titanate (BTO) nanocrystals.

[0012] (2) Preparation of APB nanocomposites:

[0013] Tetragonal barium titanate (BTO) nanocrystals were dispersed in water. While stirring, aqueous solutions of gold and palladium precursors were added dropwise. Continued stirring induced a piezoelectric potential on the surface of the tetragonal barium titanate, driving the Au content within the system. 3+ Pd 2+ In-situ reduction to metal nanoparticles and tightly loaded onto the surface of tetragonal barium titanate to form a stable heterojunction structure. After centrifugation, washing and drying, APB nanocomposite material was obtained.

[0014] (3) Preparation of APBF hydrogel:

[0015] A thermosensitive polymer was dissolved in water to prepare a thermosensitive aqueous solution. APB nanocomposite material was added and mixed evenly. The solution-gel transition occurred at physiological temperature to obtain an energy-responsive multi-catalytic nanogenerator hydrogel.

[0016] Preferably, in step (1), the titanium source is tetraethyl titanate.

[0017] Preferably, in step (1), the barium source is barium chloride.

[0018] Preferably, the concentration of the titanium source solution in step (1) is 0.05–0.2 mol / L. Preferably, the concentration of the barium source solution in step (1) is 0.1–0.4 mol / L.

[0019] Preferably, the titanium source solution and the barium source solution in step (1) are mixed in a molar ratio of Ba to Ti of (1.5 to 3):1.

[0020] Preferably, the dropping rate of the titanium source solution into the barium source solution in step (1) is 1 to 5 mL / min.

[0021] Preferably, the surfactant in step (1) is polyvinylpyrrolidone (PVP).

[0022] More preferably, the Mw of the polyvinylpyrrolidone is 8000 to 15000.

[0023] Preferably, the ratio of surfactant to titanium source in step (1) is (1-5) g: 1 mmol.

[0024] Preferably, the alkalinity in step (1) is pH=12 to 14.

[0025] Preferably, the concentration of the regulator used to adjust the pH of the system to alkalinity in step (1) is 0.5 to 2 mol / L; the regulator includes at least one of potassium hydroxide solution and sodium hydroxide solution.

[0026] Preferably, the equipment for the hydrothermal reaction in step (1) is a stainless steel high-pressure reactor lined with polytetrafluoroethylene, and the filling coefficient is controlled to be 50-80%.

[0027] Preferably, the temperature of the hydrothermal reaction in step (1) is 200-260°C and the reaction time is 12-36 hours.

[0028] Preferably, the drying in step (1) is freeze drying.

[0029] Preferably, the concentration of the tetragonal barium titanate (BTO) nanocrystals dispersed in water in step (2) is 0.05 to 0.5 mg / mL.

[0030] Preferably, in step (2), the gold precursor is chloroauric acid.

[0031] Preferably, in step (2), the palladium precursor is sodium tetrachloropalladium.

[0032] Preferably, in step (2), the molar ratio of the gold precursor to the palladium precursor is 1 ± 0.1:1.

[0033] Preferably, the concentration of the gold precursor solution in step (2) is 50–200 mmol / L.

[0034] Preferably, the concentration of the palladium precursor solution in step (2) is 50–200 mmol / L.

[0035] Preferably, in step (2), the total molar amount of gold precursor and palladium precursor to the mass ratio of tetragonal barium titanate (BTO) nanocrystals is (0.1-0.5) mmol: (2-6) mg.

[0036] Preferably, in step (2), the stirring speed is 3000-6000 rpm; the stirring time is not less than 30 minutes; more preferably 0.5-2 hours.

[0037] Preferably, the gold precursor solution and palladium precursor solution in step (2) are simultaneously added dropwise to the tetragonal barium titanate (BTO) nanocrystal dispersion.

[0038] Preferably, the dropping rate of the gold precursor solution and the palladium precursor solution in step (2) is 0.5 to 2 mL / min.

[0039] Preferably, in step (3), the thermosensitive polymer is Pluronic F127.

[0040] Preferably, the concentration of the temperature-sensitive aqueous solution in step (3) is 23-30% (w / v), more preferably 25-30% (w / v).

[0041] Preferably, after mixing evenly in step (3), the mixture is stored at 4±1℃.

[0042] Preferably, the physiological temperature in step (3) is 37±1℃.

[0043] Preferably, the concentration of the APB nanocomposite material in step (3) is 40–120 mg / mL.

[0044] Secondly, the present invention provides an energy-responsive multi-catalytic nanogenerator hydrogel prepared by the above preparation method.

[0045] This hydrogel is a thermosensitive injectable system; it exists as a flowing sol at 4°C and undergoes a rapid phase transition to form a solid hydrogel at 37°C. The Au-Pd bimetallic alloy within the system exhibits cascade enzyme activities similar to glucose oxidase (GOD), superoxide dismutase (SOD), and catalase (CAT), enabling it to deplete local glucose and efficiently scavenge reactive oxygen species (ROS). The BTO nanocrystals possess excellent piezoelectric properties, stably generating endogenous electrical signals under 1.0 MHz ultrasonic stimulation, thus achieving the conversion of ultrasonic energy into electrical signals.

[0046] Thirdly, this invention provides the application of the above-mentioned energy-responsive multi-catalytic nanogenerator hydrogel in the preparation of diabetic rotator cuff injury repair agents, tendon and bone healing tissue engineering scaffolds, chronic inflammatory microenvironment regulation materials, and ultrasound-responsive electrostimulation biomaterials.

[0047] Based on the analysis of the clinical transcriptomics dataset GSE236746, this invention targets two core obstacles to tendon and bone healing in diabetic patients: mechanotransmission impairment caused by PIEZO2 downregulation, and the vicious cycle of oxidative stress-inflammation driven by AGEs / RAGE axis activation. By specifically designing a hydrogel system with "metabolic-electro-regulatory dual regulation," it successfully overcomes the limitations of traditional, indiscriminate repair approaches.

[0048] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0049] Cascaded nanozymes reshape the anti-inflammatory microenvironment: Au-Pd bimetallic alloys possess GOD / SOD / CAT enzyme mimicry activities, which can deplete local glucose at the source and progressively eliminate various ROS such as superoxide anions, hydrogen peroxide, and hydroxyl radicals, completely blocking the glucose-ROS-AGEs / RAGE cascade reaction. This mechanism effectively inhibits the downstream MAPK / NF-κB inflammatory pathway, driving macrophages to polarize from a pro-inflammatory M1 phenotype to a reparative M2 phenotype, thus reshaping the anti-inflammatory and regenerative microenvironment.

[0050] Piezoelectric effect compensates for mechanosensing defects: Tetragonal BTO nanocrystals generate stable and continuous endogenous electrical signals under physiological ultrasound stimulation, exogenously compensating for the loss of cellular mechanosensing function caused by PIEZO2 downregulation. This electrical signal directly activates the mechanotransmission pathways of endothelial cells and bone marrow mesenchymal stem cells, significantly promoting angiogenesis, osteogenic differentiation, and chondrogenic differentiation, thereby achieving gradient tissue regeneration at the tendon-bone interface.

[0051] The process is green, efficient, and highly synergistic: The piezoelectric-driven in-situ reduction synthesis process employed in this invention eliminates the need for toxic strong reducing agents. It directly reduces metal monomers by inducing piezoelectric potential through high-speed mechanical stirring, resulting in an environmentally friendly and highly reproducible process. This not only promotes the formation of a tight heterojunction between the metal and the substrate but also ensures the stable expression and synergistic enhancement of multiple catalytic and piezoelectric functions within the composite material.

[0052] Excellent clinical applicability and in vivo repair efficacy: The Pluronic F127-based thermosensitive hydrogel not only possesses excellent shear-thinning behavior and injectability, enabling minimally invasive implantation and seamless in-situ adhesion to irregular damaged interfaces (such as the tendon-bone interface), but also continuously and stably releases nanocomposite materials during degradation, exhibiting no significant cytotoxicity and excellent biocompatibility. In diabetic animal models, it effectively promoted fibrocartilage regeneration and collagen matrix maturation, significantly improved the ultimate load and stiffness of the repaired tissue, and fully restored the structural integrity and mechanical function of the tendon-bone interface, demonstrating enormous clinical translational potential. Attached Figure Description

[0053] Figure 1 The results show the ferroelectric and piezoelectric performance characterization of the energy-responsive multi-catalytic nanogenerator in Example 2, including (A) the locally magnified XRD pattern of APB (2θ range: 43.0-46.0°), (B) the amplitude-voltage curve of APB, and (C) the phase-voltage curve of APB.

[0054] Figure 2 The results show the thermosensitive sol-gel transition behavior of the energy-responsive multi-catalytic nanogenerator hydrogel in Example 3, where (A) is the state of APBF at 4°C, (B) is the state of APBF at 37°C, and (C) is the rheological behavior of APBF.

[0055] Figure 3 The rheological properties and injectability characterization results of the energy-responsive multi-catalytic nanogenerator hydrogel in Example 3 are shown in (A) and (B) macroscopic display of the excellent molding and shaping ability of APBF, and (C) injectionability of APBF.

[0056] Figure 4 The rheological behavior of the energy-responsive multi-catalytic nanogenerator hydrogel in Example 4 is shown. Detailed Implementation

[0057] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0058] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0059] Example 1: Controllable hydrothermal synthesis of tetragonal barium titanate (BTO) nanocubes

[0060] Precursor solution preparation: Tetraethyl titanate was dissolved in anhydrous ethanol and stirred until completely dissolved to prepare a 0.1 mol / L titanium source solution A; Barium chloride (BaCl2) was dissolved in deionized water and stirred until completely dissolved to prepare a 0.2 mol / L barium source solution B.

[0061] Preparation of the mixed system: Take 15 mL of solution A and add it dropwise to 15 mL of solution B at a rate of 2 mL / min under mechanical stirring at 500 rpm, ensuring that the molar ratio of Ba to Ti is 2:1. After the addition is complete, continue stirring for 30 min. Add 4.5 g of polyvinylpyrrolidone (PVP, Mw≈10000) as a surfactant to the mixture and stir until completely dissolved. Adjust the pH of the system to 13 with 1 mol / L KOH aqueous solution and continue stirring at room temperature for 30 min to obtain a homogeneous precursor mixture.

[0062] Hydrothermal reaction: The precursor mixture was transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene, with the filling coefficient controlled at 60%. After sealing, it was placed in a forced-air drying oven and reacted at a constant temperature of 240℃ for 24 hours.

[0063] Post-processing: After the reaction was completed, the product was naturally cooled to room temperature. The precipitate was collected by centrifugation at 12,000 rpm for 30 min. The product was washed three times with anhydrous ethanol and deionized water, and the precipitate was collected by centrifugation at 12,000 rpm for 20 min after each wash. Finally, the washed product was placed in a freeze dryer and freeze-dried under vacuum at -50℃ for 24 h to obtain tetragonal BTO nanocubic powder.

[0064] Material characterization and properties:

[0065] Morphology and particle size: TEM characterization showed that the BTO prepared in this example was a uniformly dispersed cubic nanoparticle with a uniform size and an average particle size of 50±20nm, with no obvious agglomeration.

[0066] Crystal structure: XRD characterization showed that the diffraction peaks of the product were completely matched with the standard card of tetragonal BaTiO3 (JCPDS No. 05-0626), with no impurity peaks. There was obvious (002) / (200) peak splitting in the 2θ=44°~46° range, which confirmed that it was a pure tetragonal perovskite structure without cubic impurities.

[0067] Powder properties: Laser particle size analyzer test showed that the particle size distribution coefficient (PDI) of the product was 0.12, indicating excellent dispersibility; the zeta potential was -28.3mV, indicating good colloidal stability in aqueous system.

[0068] Example 2: Piezoelectric-driven in-situ reduction synthesis of gold-palladium / barium titanate (APB) nanocomposites

[0069] Preparation of substrate dispersion: Take 4 mg of BTO nano cubic powder prepared in Example 1, add it to 40 mL of deionized water, and sonicate it in an ice-water bath for 30 min at a power of 200 W for 2 s with a 3 s interval to obtain a uniform BTO aqueous dispersion without precipitation.

[0070] Piezoelectric-driven in-situ reduction: A BTO aqueous dispersion was placed in an ice-water bath. Under high-speed mechanical stirring at 4500 rpm, 1.8 mL of a 100 mmol / L chloroauric acid (HAuCl4·3H2O) aqueous solution and 1.8 mL of a 100 mmol / L sodium tetrachloropalladate (Na2PdCl4) aqueous solution were simultaneously added dropwise at a rate of 1 mL / min, ensuring a 1:1 molar ratio of Au to Pd. After the addition was complete, the reaction was continued at 4500 rpm for 1 hour. The mechanical stress generated by the high-speed stirring induced a piezoelectric potential in BTO, driving Au to undergo reduction. 3+ Pd 2+ The BTO surface is reduced in situ to form metal alloy nanoparticles.

[0071] Post-processing: After the reaction was completed, the product was centrifuged at 10,000 rpm for 20 min to collect the precipitate, washed three times with deionized water, and centrifuged to collect the product after each wash; finally, the product was placed at -50℃ for vacuum freeze-drying for 24 h to obtain APB nanocomposite powder.

[0072] Material characterization and core properties:

[0073] Morphology and interface structure: TEM characterization showed that Au-Pd alloy nanoparticles were uniformly loaded on the BTO nanocube surface, with an average particle size of 3-5 nm and no large-area agglomeration; HRTEM characterization showed that the (111) crystal plane of Au-Pd alloy and the (110) crystal plane of BTO formed a close contact without interface gaps, confirming that the two formed a stable heterojunction structure; EDS elemental mapping showed that Ba, Ti, O, Au and Pd elements were uniformly distributed, confirming the uniform loading of bimetallic alloy on the BTO surface.

[0074] Crystal and Chemical Structure: XRD characterization showed that the product retained the characteristic peaks of the tetragonal perovskite phase of BTO, while also exhibiting characteristic diffraction peaks of the Au-Pd alloy at 2θ = 38.2° and 44.4°, without any impurity peaks of single-metal Au or Pd, confirming the formation of an alloy structure. XPS characterization showed characteristic peaks of the Au 4f orbital at 84.0 eV and 87.8 eV, and characteristic peaks of the Pd 3d orbital at 335.6 eV and 340.8 eV, corresponding to metallic Au. 0 Pd 0 This confirms that the metal ions were completely reduced and there were no oxidized impurities.

[0075] Piezoelectric properties: PFM testing showed that the amplitude-voltage curve of the APB sample exhibited a typical "butterfly" shape, and the phase-voltage curve showed a standard ferroelectric hysteresis loop with a 180° flip, confirming that BTO retains excellent ferroelectric and piezoelectric properties after being loaded with Au-Pd alloy, with a piezoelectric coefficient d33 reaching 85 pC / N; at 1.0 MHz and 1.0 W / cm 2 Under ultrasonic stimulation, electrochemical workstation tests showed that APB can generate a stable piezoelectric response current with an output voltage of up to 120mV.

[0076] Catalytic performance of cascaded nanozymes: at 1.0 MHz and 1.0 W / cm² 2 Under ultrasonic conditions with a 50% duty cycle, the catalytic activity was tested using the standard colorimetric method: the APB sample with 80 μg / mL showed GOD enzyme activity of up to 15.2 U / g, SOD enzyme activity of up to 890 U / g, and CAT enzyme activity of up to 22.6 U / g, which were significantly better than the monometallic supported AB and PB samples and the pure BTO sample. The cascade catalytic reaction test showed that APB could deplete 92% of the glucose in the system within 2 hours, while controlling the conversion rate of the reaction intermediate H2O2 to above 98%, with no H2O2 accumulation.

[0077] ROS scavenging performance: 80 μg / mL APB sample showed good resistance to H2O2 and O2· - ·OH 1 The O2 removal efficiencies reached 91%, 94%, 88%, and 85%, respectively. ESR spectroscopy showed that the characteristic signal peak intensities of the four reactive oxygen species decreased by more than 90%, demonstrating a broad-spectrum and highly efficient ROS removal capability. Under ultrasonic stimulation, the ROS removal efficiency could be further improved by 15% to 20%, confirming the existence of the piezoelectric-catalytic synergistic effect.

[0078] Example 3: Preparation of Energy-Responsive Multi-Catalytic Nanogenerator Hydrogel (APBF)

[0079] Preparation of thermosensitive hydrogel matrix: Take Pluronic F127 powder and slowly add it to pre-cooled deionized water at a low temperature of 4℃. Stir continuously at a low speed of 200rpm for 12h until the powder is completely dissolved to prepare an F127 aqueous solution with a mass volume fraction of 25% (w / v). Store at 4℃ for later use.

[0080] Preparation of nanocomposite hydrogel: Take the above F127 aqueous solution and add the APB nanocomposite powder prepared in Example 2 in batches under the stirring conditions of 4℃ and 200rpm. Continue stirring for 2h until the powder is completely and uniformly dispersed, without agglomeration or precipitation. The final concentration of APB in the system is 80mg / mL. Store in a sealed container at 4℃ to obtain the energy-responsive multi-catalytic nanogenerator hydrogel (APBF) precursor of the present invention.

[0081] Material characterization and core properties:

[0082] Sol-gel transition behavior: The tube inversion experiment showed that the hydrogel was a transparent sol with good flowability at 4℃, and underwent a phase transition within 1 minute in a constant temperature environment of 37℃ to form a non-flowing, elastic milky white hydrogel. Rheological tests showed that its critical gel transition temperature (CGT, the temperature corresponding to G'=G'') was 21.5℃, which meets the requirements of physiological temperature response. At 37℃, its storage modulus G' can reach 1250Pa, and its loss modulus G'' is 180Pa, which shows good gel strength and elasticity.

[0083] Injectability and Rheological Properties: Rheological testing showed that the APBF hydrogel exhibited significant shear-thinning behavior as the shear rate increased, starting from 0.1 s⁻¹. -1 Rise to 100s -1 When the viscosity drops from 1200 Pa·s to 1.2 Pa·s, it exhibits excellent injectability; it can be smoothly extruded through a 21G syringe needle, and after extrusion, it can quickly return to a gel state in an environment of 37°C without dripping, and can be molded in situ to fill irregular spaces.

[0084] Stability and degradation performance: After 6 months of sealed storage at 4℃, the APBF hydrogel still maintains a uniform sol state with no nanoparticle sedimentation or stratification. It can still undergo normal sol-gel transition after heating, demonstrating excellent storage stability. In PBS buffer at pH 7.4, it can remain stable for more than 28 days at 37℃, with a cumulative degradation rate of 32% after 28 days. During the degradation process, APB nanocomposite materials are continuously released, and the release cycle matches the tissue repair cycle.

[0085] Ultrasonic response performance: The APBF hydrogel in its gel state at 37℃ exhibits ultrasonic response performance at 1.0 MHz and 1.0 W / cm². 2 Under ultrasonic stimulation, it can stably generate an intrinsic piezoelectric potential, and the APB nanoparticles inside the gel still maintain stable cascade catalytic activity. Ultrasonic stimulation can further improve its ROS scavenging efficiency and has stable energy response performance.

[0086] Catalytic performance of cascaded nanozymes: at 1.0 MHz and 1.0 W / cm² 2 Under ultrasonic conditions with a 50% duty cycle, the catalytic activity was tested using a standard colorimetric method: For an 80 μg / mL APBF sample, the activities of GOD-type enzymes reached 15.0 U / g, SOD-type enzymes reached 870 U / g, and CAT-type enzymes reached 22.2 U / g. The catalytic activity against H₂O₂ and O₂·⁻ was also observed. - The removal efficiencies of ·OH can reach 90%, 91%, and 86%, respectively.

[0087] Example 4: F127 hydrogels with different solid contents

[0088] Except for setting the mass-volume fraction of the F127 aqueous solution to 30% (w / v), the remaining preparation steps and process parameters were completely consistent with those in Example 3, yielding a hydrogel with a 30% solid content. Performance comparison results: The critical gel transition temperature of this sample was 22℃, and at 37℃, its storage modulus G' reached 82000 Pa, and its loss modulus G'' was 7000 Pa, exhibiting good gel strength and elasticity.

[0089] Comparative Example 1: Preparation of single-metal supported Au / BTO (AB) nanocomposites

[0090] Except for replacing the metal precursor with 3.6 mL of 100 mmol / L chloroauric acid aqueous solution and omitting the addition of sodium tetrachloropalladate, the preparation steps and process parameters were completely consistent with Example 2, yielding the AB nanocomposite material. Performance comparison results: At the same concentration (80 μg / mL), the AB sample exhibited 7.8 U / g activity for GOD-type enzymes and 10.5 U / g activity for CAT-type enzymes, with similar activity against H2O2 and O2· - The removal efficiencies of ·OH were 52%, 61%, and 48%, respectively, which were only about 50% of those of the APB sample in Example 2, confirming that the synergistic catalytic effect of the Au-Pd bimetallic alloy was significantly better than that of the single metal system.

[0091] Comparative Example 2: Preparation of Single Metal Supported Pd / BTO (PB) Nanocomposites

[0092] Except for replacing the metal precursor with 3.6 mL of 100 mmol / L sodium tetrachloropalladate aqueous solution and omitting chloroauric acid, the preparation steps and process parameters were completely consistent with Example 2, yielding PB nanocomposite materials. Performance comparison results: At the same concentration (80 μg / mL), the SOD enzyme activity of the PB sample was 420 U / g, and the GOD enzyme activity was 3.2 U / g. The activity against H2O2 and O2· - The removal efficiencies of ·OH were 65%, 58%, and 51%, respectively, and the cascade catalytic ability and ROS removal efficiency were significantly lower than those of the APB sample in Example 2.

[0093] Comparative Example 3: Au-Pd+BTO nanocomposites prepared by physical blending method

[0094] Pure Au-Pd alloy nanoparticles were first prepared using the sodium borohydride reduction method: 1.8 mL of a 100 mmol / L aqueous solution of chloroauric acid, 1.8 mL of a 100 mmol / L aqueous solution of chloropalladic acid, and 4.5 g of PVP (Mw≈10000) protective agent were mixed and stirred for 20 minutes in an ice-water bath. An excess of 0.1 mol / L ice-cold sodium borohydride solution was then rapidly added dropwise, and the mixture was vigorously stirred for 1 hour to obtain Au-Pd sol. Subsequently, 4 mg of the BTO nanocubes prepared in Example 1 were added to 40 mL of deionized water and dispersed by high-power ultrasonication for 30 minutes. The Au-Pd sol was then slowly added, and the mixture was continuously magnetically stirred at room temperature for 12 to 24 hours to achieve sufficient physical adsorption. Finally, the mixture was centrifuged at 10,000 to 12,000 rpm for 15 minutes, washed three times alternately with deionized water and anhydrous ethanol, and then freeze-dried under vacuum at -50°C for 24 hours to obtain a loose physical blend Au-Pd+BTO composite material.

[0095] Performance comparison results: TEM characterization showed that Au-Pd nanoparticles in this sample had no interface binding with BTO and exhibited severe agglomeration; under the same test conditions, its piezoelectric response current was only 32% of that of the APB sample in Example 2, and its cascade catalytic activity was only 40% of that of the APB sample. This confirms that the piezoelectric-driven in-situ reduction method of the present invention can construct a stable heterojunction interface and achieve synergistic enhancement of piezoelectric and catalytic performance, which is significantly better than the physical blending method.

[0096] Comparative Example 4: BTO nanoparticles synthesized at different hydrothermal temperatures

[0097] Except for setting the hydrothermal reaction temperature to 200℃, the other preparation steps and process parameters were completely consistent with those in Example 1, and BTO nanoparticles were obtained. Performance comparison results: XRD characterization showed that the (002) / (200) peak splitting of this sample was not obvious, and cubic BTO was the main phase; PFM test showed that its piezoelectric coefficient d33 was only 22pC / N, which was much lower than that of the tetragonal BTO sample in Example 1, confirming that pure tetragonal BTO with excellent piezoelectric properties can be prepared at a hydrothermal temperature of 240℃.

[0098] Comparative Example 5: F127 hydrogels with different solid contents

[0099] Except for setting the mass-volume fraction of the F127 aqueous solution to 20% (w / v), the remaining preparation steps and process parameters were completely consistent with those in Example 3, yielding a hydrogel with a 20% solid content. Performance comparison results: The critical gel transition temperature of this sample was 28.5℃, and the storage modulus G' at 37℃ was only 320 Pa. The gel strength was low and easily broken, making stable in-situ molding and long-term retention impossible. This confirms that a 25% F127 solid content can balance thermoresponsiveness and gel mechanical properties.

[0100] 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 method for preparing an energy-responsive multi-catalytic nanogenerator hydrogel, characterized in that, Includes the following steps: Tetragonal barium titanate nanocrystals were synthesized using a hydrothermal method. Subsequently, a gold-palladium bimetallic alloy was loaded onto the surface of BTO nanocrystals using a piezoelectric-driven in-situ reduction strategy to obtain a gold-palladium / barium titanate nanocomposite material. Finally, the gold-palladium / barium titanate nanocomposite material was dispersed in a thermosensitive hydrogel matrix to form a gel, thus obtaining an energy-responsive multi-catalytic nanogenerator hydrogel.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: (1) Add the titanium source solution dropwise to the barium source solution, add a surfactant, adjust the pH of the system to alkaline, perform hydrothermal reaction, centrifuge, wash, and dry to obtain tetragonal barium titanate nanocrystals; (2) Tetragonal barium titanate nanocrystals were dispersed in water, and gold precursor aqueous solution and palladium precursor aqueous solution were added dropwise while stirring. Stirring was continued to induce the generation of piezoelectric potential on the surface of tetragonal barium titanate, driving Au in the system. 3+ Pd 2+ In-situ reduction to metal nanoparticles and tightly loaded onto the surface of tetragonal barium titanate to form a stable heterojunction structure. After centrifugation, washing and drying, APB nanocomposite material was obtained. (3) The thermosensitive polymer was dissolved in water to prepare a thermosensitive aqueous solution. APB nanocomposite material was added and mixed evenly. The solution-gel transition occurred at physiological temperature to obtain an energy-responsive multi-catalytic nanogenerator hydrogel.

3. The preparation method according to claim 2, characterized in that, The hydrothermal reaction in step (1) is carried out at a temperature of 200–260°C for 12–36 hours. And / or, in step (1), the titanium source is tetraethyl titanate; And / or, in step (1), the barium source is barium chloride; And / or, the concentration of the titanium source solution in step (1) is 0.05–0.2 mol / L; And / or, the concentration of the barium source solution in step (1) is 0.1–0.4 mol / L; And / or, the titanium source solution and barium source solution in step (1) are mixed in a molar ratio of Ba to Ti of (1.5 to 3):1; And / or, the dropping rate of the titanium source solution in step (1) into the barium source solution is 1 to 5 mL / min.

4. The preparation method according to claim 2 or 3, characterized in that, In step (3), the thermosensitive polymer is Pluronic F127; And / or, the concentration of the thermosensitive aqueous solution in step (3) is 23-30% (w / v), more preferably 25-30% (w / v); And / or, the concentration of the APB nanocomposite material in the system in step (3) is 40 to 120 mg / mL.

5. The preparation method according to claim 2 or 3, characterized in that, In step (2), the gold precursor is chloroauric acid; And / or, in step (2), the palladium precursor is sodium tetrachloropalladium; And / or, in step (2), the molar ratio of gold precursor to palladium precursor is 1 ± 0.1:1; And / or, in step (2), the total molar amount of gold precursor and palladium precursor to the mass ratio of tetragonal barium titanate nanocrystals is (0.1-0.5) mmol: (2-6) mg.

6. The preparation method according to claim 2 or 3, characterized in that, In step (2), the concentration of the tetragonal barium titanate nanocrystals dispersed in water is 0.05–0.5 mg / mL; And / or, the concentration of the gold precursor solution in step (2) is 50–200 mmol / L; And / or, the concentration of the palladium precursor solution in step (2) is 50–200 mmol / L; And / or, the gold precursor solution and palladium precursor solution described in step (2) are simultaneously added dropwise to the tetragonal barium titanate nanocrystal dispersion; And / or, the dropping rate of the gold precursor solution and the palladium precursor solution in step (2) is 0.5 to 2 mL / min.

7. The preparation method according to claim 2 or 3, characterized in that, The surfactant mentioned in step (1) is polyvinylpyrrolidone; And / or, the ratio of surfactant to titanium source in step (1) is (1-5) g: 1 mmol; And / or, the alkalinity described in step (1) is pH = 12 to 14; And / or, the concentration of the regulator used to adjust the pH of the system to alkalinity in step (1) is 0.5 to 2 mol / L; the regulator includes at least one of potassium hydroxide solution and sodium hydroxide solution.

8. The preparation method according to claim 2 or 3, characterized in that, In step (2), the stirring speed is 3000-6000 rpm; the stirring time is not less than 30 minutes; more preferably 0.5-2 hours; And / or, after mixing thoroughly in step (3), store at 4±1℃; And / or, the physiological temperature described in step (3) is 37±1℃.

9. An energy-responsive multi-catalytic nanogenerator hydrogel prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the energy-responsive multi-catalytic nanogenerator hydrogel of claim 9 in the preparation of diabetic rotator cuff injury repair agents, tendon and bone healing tissue engineering scaffolds, chronic inflammatory microenvironment regulation materials, and ultrasound-responsive electrostimulation biomaterials.

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