Integrated zinc battery driven iontophoresis patch and preparation method and application thereof

Abstract

The application provides an integrated zinc battery driven ion introduction patch and a preparation method and application thereof, and belongs to the technical field of biological medicine.The application integrates a flexible Zn-based battery and a conductive EMP hydrogel to construct an ion introduction delivery platform activated by wound exudate, namely, an EGCG-loaded self-powered hydrogel bioelectronic patch (EMPB). Without an external power supply, the EMPB can generate a stable microelectric field after being in contact with a wet wound environment, so that the EGCG delivery is changed from passive diffusion to electrically assisted active delivery.In vitro experiments, the EMPB promotes keratinocyte migration, reduces oxidative stress and inhibits radiation-induced ferroptosis, which is related to the recovery of the NRF2 / SLC7A11 / GPX4 antioxidant axis.In vivo experiments, the EMPB reduces local oxidative stress and inflammation, enhances angiogenesis and collagen remodeling, and accelerates the repair of irradiated skin wounds.Therefore, the EMPB is a promising bioelectronic platform for treating radiation-induced skin damage.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to an integrated zinc battery-driven iontophoresis patch, its preparation method, and its application. Background Technology

[0002] Radiation therapy plays a crucial role in the entire cancer treatment process. Despite continuous advancements in high-precision radiotherapy techniques, completely avoiding exposure of normal skin within the radiation field remains challenging, leading to radiation-induced skin injury (RISI). Compared to ordinary wounds, the healing mechanism of RISI is more complex, primarily due to the persistent disruption of the local microenvironment caused by radiation, manifested as continuous oxidative stress, lipid peroxidation, chronic inflammation, and impaired microvascular perfusion.

[0003] Recent evidence suggests that ferroptosis is a crucial pathological mechanism in the development and exacerbation of RISI (Recurrent Skin Injury). Studies have shown that ionizing radiation can increase the expression of long-chain acyl-CoA synthase family member 4 (ACSL4), a key driver of ferroptosis. ACSL4 disrupts iron homeostasis and promotes membrane lipid peroxidation, ultimately leading to ferroptosis. Morphologically, ferroptosis is characterized by mitochondrial shrinkage, increased membrane density, and reduced cristae, without the nuclear condensation commonly seen in apoptosis. Furthermore, increasing research suggests that modulating ferroptosis-related targets, including glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11), can improve the repair outcomes of various refractory skin lesions. Therefore, regulating ferroptosis may be a potential therapeutic approach for RISI.

[0004] Topical drug therapy is one of the most commonly used methods in the management of RISI (Related Inflammatory Skin Infection). However, traditional topical drug delivery mainly relies on passive diffusion, which is easily affected by the skin barrier and wound exudate, resulting in insufficient drug penetration into the wound bed and inadequate local exposure, making it difficult to effectively inhibit ferroptosis. The natural polyphenol EGCG possesses the ability to scavenge reactive oxygen species (ROS) and chelate free iron, making it a potent antioxidant. Importantly, EGCG can effectively inhibit ferroptosis by upregulating the NRF2 / SLC7A11 / GPX4 defense pathway. Therefore, EGCG is considered a promising candidate drug for modulating the RISI microenvironment. However, due to its chemical structure being rich in phenolic hydroxyl groups, EGCG is prone to auto-oxidation and polymerization under physiological conditions, leading to a rapid loss of biological activity. Furthermore, the hydrophilicity of EGCG limits its penetration of the intact stratum corneum in free form, and its poor local retention makes it easily diluted and inactivated by wound exudate, thus failing to maintain sufficient bioavailability at the lesion site. Although various carriers have been used for local EGCG delivery, these systems typically rely on passive release, lacking precise control over delivery kinetics and tissue penetration, thus limiting their efficacy in chronic wound healing. This superficial and inefficient passive exposure is insufficient to adequately suppress persistent ferroptosis activity within the wound bed. Therefore, overcoming the limitations of passive diffusion and achieving controllable, efficient, and active delivery of antiferroptosis drugs in RISI lesions remains a crucial problem to be solved.

[0005] Iontophoresis, as an active delivery strategy, has received increasing attention in the field of local drug delivery in recent years. By applying a low-intensity DC electric field, iontophoresis can utilize the synergistic effect of electroosmotic fluid dragging and electromigration to drive charged or polar molecules into the wound bed and surrounding tissues, thereby transforming drug transport from passive diffusion to active delivery and increasing local drug exposure at the target site. Unlike passive release driven solely by concentration gradients, iontophoresis enables more controllable and efficient molecular delivery and has been shown to improve the local bioavailability of various therapeutic drugs. In a related study, Zhou et al. reported a self-powered percutaneous delivery platform for iontophoresis using an integrated magnesium battery, thereby promoting precise drug release and accelerating psoriasis healing. Furthermore, the current generated during iontophoresis can also act as an independent biophysical regulator, actively guiding cell movement and proliferation, thereby promoting comprehensive wound repair.

[0006] However, applying existing iontophoresis systems to RISI wounds still presents technical challenges. First, traditional devices typically rely on bulky external power supplies and wired connections, imposing a physical and psychological burden on patients. Second, most iontophoresis platforms employ a layered structure of conductive electrodes and independent drug reservoirs, inevitably introducing significant interfacial impedance between layers. This not only dissipates a large amount of electric field energy but also significantly reduces drug delivery efficiency.

[0007] Therefore, developing a wearable iontophoresis platform that combines a lightweight, safe power source with an integrated electrode / drug reservoir could significantly improve therapeutic performance while enhancing patient comfort and usability. This is a problem that urgently needs to be addressed. Summary of the Invention

[0008] This invention aims to solve the aforementioned technical problems by providing an integrated zinc battery-driven iontophoresis patch, its preparation method, and its application. The technical objective of this invention is to provide a lightweight, safe, and wearable iontophoresis platform that integrates an integrated electrode / drug reservoir for radiation-induced skin damage caused by ferroptosis, thereby significantly improving therapeutic performance while enhancing patient comfort and usability.

[0009] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: This invention first provides a method for preparing an integrated zinc battery-driven iontophoresis patch, comprising the following steps: (1) MXene nanosheets were dispersed in water to obtain an MXene dispersion; (2) The MXene dispersion obtained in step (1) is mixed with polyvinyl alcohol and stirred at high temperature to prepare a PVA / MXene composite solution; (3) Add EGCG to the PVA / MXene composite solution obtained in step (2), and the mixture is subjected to freeze-thaw cycles to form a composite hydrogel; (4) Using the composite hydrogel obtained in step (3) as the cathode of the battery, Zn foil as the anode, and PBS as the electrolyte, a zinc-ion hydrogel battery is assembled to prepare an integrated zinc battery-driven ion-importing patch.

[0010] To address the challenge of RISI (Recurrent Esophageal Infection) driven by ferroptosis activation, this invention proposes an iontophoresis patch system (EMPB) activated by wound exudate and loaded with the natural polyphenol EGCG. Unlike traditional local dressings or passive drug delivery systems, EMPB aims to overcome the limited penetration and unstable local exposure caused by passive diffusion. In terms of materials and structural design, this invention introduces a zinc battery as an in-situ power source. The wound exudate activates the zinc battery, enabling a continuous output of low-intensity DC microcurrent, thereby transforming EGCG delivery from passive diffusion to electrically assisted active transport, while avoiding the bulky external power source required by traditional iontophoresis. Further design incorporates an integrated MXene / PVA porous hydrogel as a unified carrier, serving as both the battery cathode and the therapeutic layer. Specifically, PVA, through freeze-thaw processing, forms a stable, flexible three-dimensional porous network with abundant hydration channels, providing microchannels for drug delivery and release. The introduction of the highly conductive MXene enhances electron transport and charge transfer efficiency, enabling the battery output to be more effectively converted into interfacial ion flux and a stable micro-electric field. Furthermore, loading EGCG into this conductive hydrogel can impart anti-ferrode death activity by activating the NRF2 / SLC7A11 / GPX4 antioxidant axis.

[0011] Unexpectedly, the EMPB ion-importing patch prepared in this invention improves the mechanical and electrochemical properties of the hydrogel. As shown in the examples, compared with MP, EMP retains the porous framework while exhibiting a denser pore wall morphology. Through the introduction of EGCG, EGCG, MXene, and PVA form stable intermolecular interactions, enhancing network stability and forming a denser microstructure. This helps maintain the integrity of the hydration network under moist wound conditions, improving the mechanical properties of the hydrogel and exhibiting better structural durability and operational stability under moist wound conditions. On the other hand, after the introduction of EGCG, the current response of the EMP hydrogel electrode is significantly higher than that of the MP control. This performance improvement stems from the formation of a denser and continuous conductive network induced by EGCG, thereby promoting electrochemical activity and charge transfer capability, and ensuring stable energy output.

[0012] Importantly, by integrating the conductive electrode and drug reservoir into a single structure, this invention significantly reduces interfacial impedance and ion transport losses caused by poor interlayer contact in traditional stacked structures. Mechanistically, this low-impedance integrated electrode maximizes the driving efficiency of the micro-electric field and achieves field-driven EGCG transport and local enrichment in the wound bed through the combined effects of electroosmosis and electromigration, while synergistically promoting healing with the effects of electrical stimulation.

[0013] The iontophoresis patch of this invention was systematically evaluated in an in vitro irradiated epidermal cell model and an in vivo rat RISI model, demonstrating its ability to regulate ferroptosis, inflammation, and tissue remodeling, and highlighting its therapeutic potential in inhibiting ferroptosis and accelerating wound healing. Overall, this invention establishes a wearable hydrogel-based bioelectronic patch for RISI-targeted regulation, showing promising translational potential.

[0014] Furthermore, the preparation method of the MXene nanosheets is as follows: Ti3AlC2 powder is slowly added to a mixture of LiF and HCl, stirred at 35°C for 24 h, the resulting product is centrifuged and washed, the supernatant is collected and freeze-dried for 24 h to obtain MXene nanosheets.

[0015] Furthermore, the stirring reaction conditions described in step (2) are: stirring at 95°C and 600 rpm for 5 hours.

[0016] Furthermore, in step (2), the weight ratio of MXene dispersion to polyvinyl alcohol is 1:100.

[0017] Furthermore, the amount of EGCG used in step (3) is 0.01-0.1 wt%.

[0018] Furthermore, the freeze-thaw cycle in step (3) is repeated three times, and the freeze-thaw conditions for each cycle are -20°C for 4 hours.

[0019] A second objective of this invention is to provide an integrated zinc battery-driven iontophoresis patch prepared by the method described above.

[0020] A third objective of this invention is to provide the application of the integrated zinc battery-driven iontophoresis patch described above in the preparation of drugs or medical devices for treating radiation-induced skin damage.

[0021] A fourth objective of this invention is to provide the application of the integrated zinc battery-driven iontophoresis patch described above in the preparation of a medicament for treating ferroptosis inhibitors.

[0022] A fifth objective of this invention is to provide the application of the integrated zinc battery-driven iontophoresis patch described above in the fabrication of wearable devices for treating radiation-induced skin damage.

[0023] The beneficial effects of this invention are as follows: (1) This invention develops an iontophoresis patch activated by wound exudate and containing a built-in zinc battery, named Epigallocatechin Gallate (EGCG) Loaded MXene / Polyvinyl Alcohol Battery (EMPB). The integrated porous EGCG / MXene / PVA (EMP) conductive hydrogel serves as both the zinc battery cathode and the drug reservoir, reducing the interfacial resistance between the electrode layer and the drug reservoir. After being attached to the wound bed, the EMPB patch uses wound exudate as an electrolyte to activate the battery and generates a stable direct current (DC) micro-electric field to drive iontophoresis, thereby promoting the efficient delivery of EGCG through electroosmotic flow.

[0024] (2) In vitro experiments showed that the electrical stimulation generated by the patch accelerated cell migration, while actively delivered EGCG upregulated the NRF2 / SLC7A11 / GPX4 axis to inhibit radiation-induced ferroptosis. In vivo experiments showed that EMPB inhibited ferroptosis and inflammation, reduced oxidative damage, promoted angiogenesis and collagen remodeling, and ultimately achieved a wound closure rate of 89.3% by day 14. Overall, EMPB is a promising bioelectronic platform for accelerating RISI healing. Attached Figure Description

[0025] Figure 1 Characterization of EMP; (AB) SEM images and EDS elemental distribution maps of cross-linked materials; scale bar: 50 μm; (C) FTIR spectra of PVA, EGCG, MXene / PVA and EGCG / MXene / PVA; (D) Raman spectra of MXene / PVA and EGCG / MXene / PVA; (EF) XPS spectra in the C 1s region and O 1s region; (G) Tensile stress-strain curves of different hydrogels; (H) Elastic modulus and toughness of hydrogels; (I) Strain scanning rheological analysis of EGCG / MXene / PVA; (J) Swelling behavior of PVA, MXene / PVA and EGCG / MXene / PVA over time.

[0026] Figure 2Electrochemical performance, self-powered output, and iontophoresis release performance of EMPB; (A) Current-potential (IV) curves of PVA, MXene / PVA, and EGCG / MXene / PVA hydrogels; (BC) Nyquist plots and magnified views of the corresponding high-frequency regions of different hydrogels; (D) Bode plots of hydrogels; (E) Ionic and conductivity data of MXene / PVA and EGCG / MXene / PVA hydrogels; (F) Cyclic voltammetry (CV) curves of hydrogels at different scan rates; (G) Voltage and corresponding current density waveforms during pulsed electrical stimulation; (H) Charge injection capacity over 500 cycles, with insets showing current density waveforms at the 1st and 500th cycles; (I) Schematic diagram of the working mechanism of the self-powered zinc-based battery system; (JK) Open-circuit voltage and short-circuit current of the patch; (L) Discharge potential curves of the system under different external load resistances; (MN) Control group (0-15 min) and patch group (0-5 min). (min) Photographs of the in vitro permeation process; (O) Cumulative release percentage curves of the control group and the patch group.

[0027] Figure 3 Biological effects of EMPB on HaCaT cells; (A) HaCaT cell live / dead staining results. Scale bar: 200 μm; (B) CCK-8 assay under different treatments; (C) Scratch closure rate statistics; (D) Representative images of clonogenic assay; (E) HaCaT cell migration images under different treatments. Scale bar: 500 μm; (F) Representative H&E staining images of major rat organs after different treatments. Scale bar: 50 μm; ns (no statistical difference), *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0028] Figure 4 To alleviate oxidative stress-induced ferroptosis in HaCaT cells using EMPB; (A, D) ROS expression levels in HaCaT cells were quantified using the DCFH-DA probe; scale bar: 100 μm; (B, E) Fe²⁺ accumulation in HaCaT cells was evaluated using the FerroOrange fluorescent probe; scale bar: 100 μm; (C, F) GPX4 immunofluorescence and mean fluorescence intensity. Scale bar: 10 μm; ns (no statistical difference), *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0029] Figure 5EMPB alleviates radiation-induced ferroptosis by restoring the NRF2 / SLC7A11 / GPX4 axis and inhibiting lipid peroxidation signaling; (AD) RT-qPCR was used to quantify the mRNA expression levels of GPX4, SLC7A11, ACSL4, and NOX1; (E) TEM images of mitochondrial morphology in different groups. Scale bars: 4 μm and 1 μm; (FI) Western blot analysis was used to analyze the protein expression levels of NRF2, GPX4, and SLC7A11; ns (no statistical difference), *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0030] Figure 6 The effects of EMPB treatment on RISI in vivo; (A) Schematic diagram of animal treatment process; (B) Quantitative analysis of body weight in each group; (C) Appearance images of different treatment groups (Control, X-ray, MP, EMP, EMPB) on days 1, 3, 7, and 14; scale bar: 20 mm. (D) Quantitative analysis of wound area; (E) H&E and Masson staining images showing skin tissue structure and collagen arrangement, scale bar: 50 μm; (FG) Quantitative analysis of inflammatory cell number and collagen deposition; (H) Legend of different treatment groups; ns (no statistical difference), *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0031] Figure 7 Effects of material treatment on tissue angiogenesis, ferroptosis, and inflammatory cytokines; (A) Immunohistochemical images of CD31 and GPX4 in different groups, scale bar: 50 μm; (BC) Quantitative immunohistochemical analysis of CD31 and GPX4; (D) Quantitative immunofluorescence analysis of IL-1β; (E) Immunofluorescence staining images of IL-1β, TNF-α, IL-6, and DHE in different groups, scale bar: 50 μm; (FH) Quantitative immunofluorescence analysis of TNF-α, IL-6, and DHE; (n = 3, ns (no statistical difference), *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001).

[0032] Figure 8 For RNA-seq results analysis; (A) differentially expressed gene heatmap; (B) volcano map of differentially expressed genes between EMPB and X-ray; (CD) gene set enrichment analysis (GSEA); (EF) KEGG and GO pathway enrichment analysis.

[0033] Figure 9A schematic diagram illustrating the therapeutic mechanism of EMPB for RISI management.

[0034] Figure 10 These are photographs of the patch of the present invention under electrochemical testing conditions and when applied to a rat wound model.

[0035] Figure 11 The specific capacitance of the MXene / PVA electrode and the original PVA electrode varies with the scan rate. Throughout the scan rate range, the MXene / PVA electrode exhibits a significantly higher specific capacitance and maintains better capacitance retention at higher scan rates, indicating that the conductive network formed by introducing MXene enhances charge storage capacity and accelerates ion transport.

[0036] Figure 12 The electrochemical stability of the MXene / PVA electrode is shown in the following curves: capacitance retention versus cycle number, indicating that it retains nearly 100% of its capacitance after 500 charge-discharge cycles; cyclic voltammetry (CV) curves of the MXene / PVA electrode during the first cycle; CV curves after the 500th cycle; the almost overlapping CV curves and high capacitance retention indicate that the MXene / PVA electrode exhibits excellent electrochemical reversibility and long-term stability.

[0037] Figure 13 The charge injection behavior and cycling stability of the MXene / PVA electrode are shown. The transient current responses of the 1st and 500th cycles recorded under voltage step are almost identical. The amplified transient current density curves of the 1st and 500th cycles are shown. The consistent peak current density and decay behavior indicate that the charge injection capability is stable and the electrode / electrolyte interface is stable during repeated cycling.

[0038] Figure 14 The figure shows DNA damage in HaCaT cells after irradiation. The scale bar is 10 micrometers.

[0039] Figure 15 Gene set enrichment analysis (GSEA).

[0040] Figure 16 (A) High-resolution X-ray photoelectron spectra of pristine montmorillonite and high-resolution X-ray photoelectron spectra of the EGCG / MXene composite; (B) Cumulative release percentages of EGCG / PVA and EGCG / MXene / PVA hydrogels in simulated wound exudate; (C) Remaining mass percentages of EGCG / PVA and EGCG / MXene / PVA hydrogels.

[0041] Figure 17 (A) The cumulative release curve of zinc ions in the EMPB suture patch over 14 days; (B) The change of pH value of the surrounding medium over time over 14 days. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in detail below with reference to embodiments. It should be noted that the following embodiments are for explanation and illustration only and are not intended to limit the invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description are still within the scope of protection of this invention.

[0043] Example 1

[0044] 1. Synthesis of EMP hydrogel Ti3AlC2 powder was slowly added to a LiF / HCl mixture and stirred at 35°C for 24 h. After centrifugation and multiple washings, the supernatant was collected and freeze-dried for 24 h, denoted as MXene. Simultaneously, the MXene dispersion and PVA (polyvinyl alcohol) were added to deionized water at a weight ratio of 0.1 wt% (MXene dispersion to polyvinyl alcohol weight ratio of 1:100), and stirred at 95°C and 600 rpm for 5 h to prepare a PVA / MXene solution. EGCG was added after the solution cooled. The resulting mixture underwent three freeze-thaw cycles (−20°C, 4 h each) to form a hydrogel, named EMP, which was stored at 4°C for subsequent use.

[0045] The hydrogel prepared solely from PVA (polyvinyl alcohol) and 0.1% MXene dispersion is named MP.

[0046] 2. Characterization of EMP hydrogels The surface morphology, elemental distribution, and chemical structure of the prepared hydrogel were systematically and comprehensively characterized using SEM (Thermo Scientific Apreo 2C), EDS (OXFORD ULTIM Max65), XPS (Thermo Fisher K-Alpha), and FTIR (Thermo Fisher Nicolet iS10).

[0047] 3. In vitro EGCG release In vitro EGCG release curves were determined using a dynamic dialysis method. EGCG-loaded hydrogel samples (including EGCG / PVA and EGCG / MXene / PVA hydrogels) with the same initial EGCG content were encapsulated in 3.5 kDa MWCO dialysis bags and placed in a receptor chamber containing 10 mL of PBS. To simulate physiological conditions and promote uniform substance exchange, the experimental system was placed in a shaker at 37°C and 100 rpm. At predetermined time points, 1 mL of external release medium was collected, and an equal volume of fresh PBS was added to maintain the leak conditions. Subsequently, the EGCG concentration in these samples was quantified using UV-vis spectrophotometry, and the cumulative release percentage was calculated accordingly.

[0048] 4. Swelling rate determination To evaluate the swelling behavior of the hydrogel, the hydrogel was immersed in phosphate-buffered saline (PBS) at 37°C. The weight of the hydrogel was measured at 2, 4, 6, 12, and 24 h. The swelling ratio (SR) was calculated using the following formula: ; In the formula, W0 and Ws represent the weight of the EMP hydrogel before and after swelling, respectively.

[0049] 5. Mechanical properties To evaluate mechanical properties, EMP hydrogel samples were prepared into dumbbell-shaped geometries (20 × 10 × 2 mm). A Mark-10 universal testing machine was used at a speed of 0.5 mm·min⁻¹. -1 Uniaxial tensile tests were conducted at a constant beam speed. The elastic modulus was calculated from the linear region of the stress-strain curve, and the toughness was obtained by integrating the area under the curve. Furthermore, dynamic viscoelastic properties were characterized using a rheometer (TA Instruments, New Castle, DE). Oscillatory strain scans (0.1% to 100%) were performed on hydrogel discs (8 mm in diameter, 2.4 mm thick) to monitor changes in storage modulus and loss modulus.

[0050] 6. Electrical and electrochemical characterization First, the conductivity of the EMP hydrogel was evaluated using cyclic voltammetry (CV) in a two-electrode system. Subsequently, electrochemical characterization was performed in 0.01 M PBS solution using an electrochemical analyzer (Chenhua CHI660E). The experimental cell consisted of a three-electrode system, with the prepared hydrogel patch (1 cm × 1 cm × 0.3 cm) serving as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt wire as the auxiliary electrode.

[0051] To evaluate ion transport capability, an electrode sample (1×1×0.3 cm) was subjected to electrochemical impedance spectroscopy (EIS). Data were acquired over a wide frequency range from 100 kHz to 0.001 Hz by applying an amplitude of 5 mV. Based on the generated Nyquist plot, the ionic conductivity (σ) of the sample was derived using formula (2): ; Where σ is the ionic conductivity (S / m), R (Ω) is the bulk resistance of the hydrogel electrode obtained from the high-frequency intercept of the EIS plot, and L and A are the thickness and area of ​​the hydrogel electrode, respectively.

[0052] The charge injection capacity (CIC) of the hydrogel samples was determined by CV and STEP methods. The CV scan rate was 5–100 mV / s, and the voltage range was -0.4 to 0.6 V. The STEP method used an electrochemical workstation to apply a ±0.5 V biphasic pulse. The charge injection capacity (CIC) was calculated using the following formula: ; Where Qc is the total charge passing through the anode, Qa is the total charge passing through the cathode (C), and A is the electrode area (cm²). 2 ).

[0053] A zinc-ion hydrogel battery (EMPB) was assembled using EMP hydrogel as the cathode, Zn foil as the anode, and PBS as the electrolyte. The open-circuit voltage, short-circuit current, and discharge potential of the battery under external load were measured using a digital multimeter (Keithley, DMM6500).

[0054] 7. In vitro cell compatibility The biocompatibility of EMPB was evaluated using HaCaT cells. HaCaT cells were purchased from Kingsource Biotechnology Co., Ltd. (Shanghai, China). Briefly, hydrogels were placed in the upper chamber of a 24-well Transwell plate (Corning, USA), and cells were seeded in the lower chamber. After 1 and 3 days of culture, cells were stained with Calcein-AM / PI staining solution and incubated for 30 min. Live cells (green) and dead cells (red) were observed using a fluorescence microscope (Zeiss, Axio). For the CCK-8 assay, cells were incubated with reagents (Beyotime, China) for 1 h from day 1 to day 3, and absorbance was recorded at 450 nm using a multi-plate reader.

[0055] 8. Cell clone formation experiment HaCaT cells were stored at a density of 2 × 10⁶ cells per well. 3Cells were seeded at a density in 6-well plates and cultured at 37°C for 12 h. Subsequently, the experimental group of cells was exposed to 10 Gy X-rays. Cells were then treated with different materials. Cell images were taken after 7 days.

[0056] 9. Intracellular ROS Detection Experiment Intracellular ROS generation was evaluated using the DCFH-DA fluorescent probe. First, 2×10⁻⁶ cells were used... 5 HaCaT cells were seeded into each well of a 24-well culture plate. Twelve h after seeding, designated groups were irradiated with 10 Gy X-rays, followed by appropriate experimental treatments for 24 h. For ROS assay, DCFH-DA was diluted 1:1000 and added to the cell culture, and incubated at 37°C in the dark for 20 min. Samples were then washed with PBS and observed immediately under a fluorescence microscope.

[0057] 10. Free iron level detection To evaluate intracellular free iron (Fe) 2+ Accumulation of HaCaT cells (2×10⁻⁶) 5 Cells were seeded at 10 g / well in 24-well plates and cultured for 12 h. After exposure to 10 Gy X-rays, they were incubated for another 24 h under specified experimental conditions. Following treatment, cells were washed with PBS and stained with 1 μM FerroOrange probe (Dojindo, F374) in serum-free medium at 37°C in the dark for 30 min. Intracellular fluorescence was observed immediately after routine PBS washing using a fluorescence microscope.

[0058] 11. GPX4 Immunofluorescence Staining Intracellular GPX4 levels were detected using confocal microscopy. First, 2 × 10⁶ cells were seeded in confocal culture dishes. 5 HaCaT cells were collected. After 12 h of adhesion, the designated experimental groups were irradiated with 10 Gy X-rays and treated accordingly for 24 h. Cells were then fixed with 4% paraformaldehyde (at room temperature for 15 min) and immediately blocked for 15 min. Cells were then incubated overnight at 4°C with GPX4 primary antibody. After 1 h of incubation with secondary antibody in the dark, representative fluorescence signals were recorded using a confocal laser scanning microscope (CLSM).

[0059] 12. Intracellular DNA Damage Experiment Radiation-related DNA damage was evaluated using γ-H2AX immunofluorescence staining. In short, HaCaT cells (2 × 10⁻⁶) were used. 5Cells were seeded in confocal culture dishes and cultured for 12 h, followed by exposure to 10 Gy X-rays. After irradiation, cells underwent their respective experimental treatments for 24 h. Samples were then fixed with 4% paraformaldehyde (15 min) and treated with standard blocking solution at room temperature for 15 min. For target detection, cells were incubated overnight at 4°C with rabbit monoclonal anti-γ-H2AX primary antibody. Secondary antibody was then incubated at room temperature in the dark for 1 h. Finally, fluorescence signals were observed using CLSM.

[0060] 13. RT-qPCR HaCaT cells (5×10) 5 Cells were seeded in 6-well plates and treated with different methods. After incubation, cells were gently washed with cold PBS and lysed directly in the wells. Total RNA was extracted using an RNA extraction kit, and its quality and concentration were assessed spectrophotometrically. After reverse transcription to complementary DNA (cDNA), mRNA expression levels were detected by RT-qPCR. Primer sequences are shown in Table 1.

[0061] Table 1. List of primers for qRT-PCR amplification

[0062] 14. Western Blotting To evaluate specific protein expression, HaCaT cells (irradiated with 10 Gy X-rays at 1 Gy / min) were lysed with RIPA buffer. The lysate was sonicated and ultracentrifuged to obtain a clear lysate, which was then mixed with 5× loading buffer (v / v, 4:1) and heat-denatured at 100 °C for 15 min. Western blot analysis was performed using primary antibodies specifically targeting NRF2, GPX4, and SLC7A11, and normalization was performed using anti-β-actin (Huabio, China). After secondary antibody binding, target protein bands were captured using a chemiluminescence imaging system.

[0063] 15. Cell migration experiment HaCaT cells (5×10) 5 Cells were seeded in 6-well plates and cultured to 90% confluence. A monolayer of cells was mechanically scraped and washed with PBS, followed by the addition of appropriate serum-free conditioned medium. Cells were then exposed to 10 Gy X-rays and co-incubated with the specified treatment. Migration behavior was recorded by microscopy at 0 h and 24 h, and the migration area was quantitatively analyzed using ImageJ software.

[0064] 16. Cell structure observation Twenty-four hours after irradiation, cells were fixed with 2.5% glutaraldehyde, dehydrated with graded ethanol, and then embedded in epoxy resin. Ultrathin sections (60–90 nm) were placed on copper grids, double-stained with uranium acetate and lead citrate, and then imaged by transmission electron microscopy to evaluate ultrastructural changes.

[0065] 17. Animal experiments All animal experimental procedures were ethically approved by the Animal Protection and Experimentation Committee of Soochow University (ethics approval number: 2023-R-116). Forty 6–8-week-old male SD rats were housed in a 12-hour light / 12-hour dark environment. After back hair removal, the rats were divided into five groups (n=8 per group): (1) control group; (2) X-ray group; (3) MP group; (4) EMP group; (5) EMPB group. The rats were anesthetized with pentobarbital (5%, 50 mg / kg). After back hair removal, the rats were irradiated with 30 Gy X-rays (Faxitron Cell Rad, USA). The radiation was targeted at a circular area with a diameter of 10 mm on the back of the rats, and other areas were shielded with lead plates to avoid exposure. The irradiated skin in the midline of the back of each rat was then carefully excised with fine ophthalmic scissors to create a standardized full-thickness circular defect with a diameter of 10 mm. MP, EMP and EMPB dressings were applied to the wound on the back of the rats after the operation. The rats in each group were sacrificed on day 14 after radiation and the skin was collected for histopathological analysis. In addition, fresh flap tissue (3 animals per group) was collected from the X-ray and EMPB groups for transcriptome RNA-seq analysis.

[0066] 18. Skin histology and immunofluorescence analysis Rat dorsal skin was fixed in 4% paraformaldehyde for 24 h, then embedded in paraffin and sectioned. The tissue sections were then stained with H&E and Masson staining. Primary antibodies (anti-IL-1β, anti-IL-6, and anti-TNF-α) and secondary antibodies were added sequentially, and the nuclei were stained with DAPI. Fluorescence images were acquired using a fluorescence microscope.

[0067] 19. ROS level detection in skin tissue ROS levels in wound tissue were detected using a dihydroethidium (DHE) fluorescent probe. Tissue sections were incubated with DHE working solution at 37°C in the dark for 30 min. After incubation, sections were washed three times with PBS (5 min each time) and then mounted with a DAPI-containing anti-fluorescence quenching mounting medium. Fluorescence signals were observed and acquired using a fluorescence microscope.

[0068] 20. Immunohistochemical staining Skin samples were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned into microscopic sections. After standard dewaxing and antigen retrieval, the sections were incubated with specific primary antibodies (anti-GPX4, anti-CD31), followed by the addition of corresponding HRP-labeled secondary antibodies. DAB reagent was used for staining, and hematoxylin was used for nuclear counterstaining. Histological characteristics were recorded under a microscope.

[0069] 21. Statistical Analysis All data are expressed as mean ± standard deviation (SD) of three independent experiments. Statistical analysis was performed using GraphPadPrism (Version 10.0) and Origin software (Version 2018). Student's t-test was used for comparisons between two groups, and one-way ANOVA was used for comparisons among multiple groups. Significance levels are expressed as follows: *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, indicating statistical significance; ns indicates no significant difference.

[0070] Experimental Example 1 1. Preparation and characterization of EMPB Ionizing radiation-induced ferroptosis is one of the reasons why RISI (recurrent radiative inflammatory disease) is difficult to heal. To develop a wearable, self-powered patch for local intervention of RISI, we designed EMPB (Emergency Medical Device Pad) to enable active drug delivery and effectively reduce ferroptosis within the wound bed. The core functional layer of EMPB needs to simultaneously possess skin adhesion and biocompatibility, an electronically and ionicly conductive microenvironment, reliable drug loading and active release capabilities, and structural integrity under moist wound interface and dynamic adhesion conditions.

[0071] Among various synthetic materials, PVA stands out as a water-soluble, biodegradable, and intrinsically non-toxic polymer. Therefore, due to its excellent biocompatibility and ease of processing, PVA has been widely used in the biomedical field. MXene, a large family of two-dimensional transition metal carbides / nitrides, is a multifunctional biomaterial due to its excellent electrical conductivity, photothermal properties, and biocompatibility. Based on these requirements, we used PVA as the hydrogel matrix and introduced MXene to construct a composite network to promote efficient electron and ion transport while stabilizing the interface. MXene was first dispersed in water and then mixed with a PVA precursor solution under vigorous stirring to obtain a homogeneous suspension.

[0072] Thanks to the abundant hydroxyl groups (-OH) on the PVA chains, they can form extensive hydrogen bonds with the hydrophilic end groups of MXene, thereby inhibiting MXene recombination and promoting its uniform dispersion. During gelation, the PVA chains further form physically cross-linked regions, while the MXene sheets are fixed and anchored within the formed three-dimensional polymer network. This results in a robust MXene / PVA (MP) composite hydrogel with high water retention and continuous hydration channels, supporting efficient electron and ion transport under humid conditions. Furthermore, the two-dimensional MXene filler enhances the conductivity of the hydrogel matrix and improves interfacial integrity, forming a mechanically robust electronic / ionic conductive platform suitable for bioelectronic or iontophoresis applications. Subsequently, we loaded the natural polyphenol EGCG into the MP hydrogel, forming EGCG / MXene / PVA (EMP), thereby introducing therapeutic functions while enhancing intermolecular interactions within the hydrogel network.

[0073] To further confirm the microstructural characteristics of the hydrogel network, we performed scanning electron microscopy (SEM). The results showed that hydrogels with different formulations all exhibited a typical interconnected porous structure. Low-magnification images revealed a uniform pore distribution, while high-magnification images further confirmed good channel connectivity, providing a structural basis for the material's gas permeability, water absorption and swelling behavior, and ion migration. Compared to MP, EMP retained the porous framework while exhibiting a denser pore wall morphology, suggesting that the introduction of EGCG helps enhance network stability. Figure 1 (A, B). This denser microstructure may help maintain the integrity of the hydration network under moist wound conditions, consistent with subsequent observations of enhanced mechanical robustness and more controllable swelling behavior in the composite hydrogel.

[0074] To verify the homogeneity of the composition and the successful introduction of components, energy-dispersive X-ray spectroscopy (EDS) elemental mapping analysis revealed that C, N, O, and Ti elements exhibited a highly uniform spatial distribution within the hydrogel matrix. The presence and uniformity of Ti directly support the successful integration of MXene without significant aggregation or phase separation. The three-dimensional conductive network accelerates electron and ion transport, thereby better coupling with the intrinsic electric field and achieving excellent electrochemical performance.

[0075] At the chemical structure level, Fourier transform infrared (FTIR) spectroscopy retained the characteristic absorption peaks of PVA and MXene, while the introduction of EGCG brought about EGCG-related features and peak shape changes. Overall, the spectrum showed multi-component superposition characteristics, accompanied by some peak shifts and intensity changes, indicating that EGCG, MXene, and PVA were successfully integrated and formed stable intermolecular interactions. Figure 1(C). Raman spectroscopy provided supplementary evidence: EMP simultaneously exhibited MXene-related vibrational characteristics and EGCG characteristic peaks (marked with a red asterisk), further confirming the formation of the composite structure. Figure 1 (D).

[0076] To further analyze the interfacial chemical environment after recombination, X-ray photoelectron spectroscopy (XPS) analysis showed that the high-resolution C 1s and O 1s spectra could be decomposed into multiple components, corresponding to oxygen-containing environments such as CC / C=C, CO, and O-Ti and OH, respectively. Figure 1 (E, F). Notably, the MXene-related peak shifted slightly from 532.04 eV to 531.92 eV after EGCG loading, indicating a shift towards lower binding energies, suggesting potential interfacial interactions between EGCG and MXene. These results indicate diverse bonding states and interfacial chemical regulation within the composite system, supporting the view that the introduction of EGCG is not a simple physical mixing process, but rather may enhance network stability through hydrogen bonding and interfacial interactions. Figure 16 (A)

[0077] We further evaluated EGCG release behavior in PBS at pH 7.4 to simulate a moist wound environment. Compared to EGCG / PVA, EGCG / MXene / PVA exhibited a slower and more sustained EGCG release profile. Figure 16 (B). Furthermore, mass retention experiments showed that during the 10-day observation period, the residual mass of EGCG / MXene / PVA was consistently higher than that of EGCG / PVA, suggesting that the composite hydrogel exhibits better structural stability under simulated wetting conditions. Figure 16 (C). Overall, the sustained EGCG release and improved quality maintenance further support the stabilizing role of the MXene / PVA network in maintaining EGCG loading and hydrogel integrity.

[0078] Improved mechanical robustness is crucial for maintaining structural integrity during wound healing. Considering the mechanical demands of wearable patches on curved skin surfaces and under dynamic conditions, stress-strain curves show that EMP exhibits higher tensile strength than pure PVA and MP, accompanied by a significant increase in elastic modulus. These results indicate that the composite and drug loading synergistically enhance mechanical properties, enabling the material to maintain fit while possessing better resistance to deformation and tension. Figure 1 (G, H). In wound management, the therapeutic efficacy of hydrogels largely depends on their swelling properties, as these are crucial for ensuring material exchange and controlled delivery to the target site. Rheological testing further revealed that the storage modulus (G′) was significantly higher than the loss modulus (G″), suggesting an elastically dominated gel state, which is beneficial for structural integrity during prolonged wear. Figure 1(I). Furthermore, swelling experiments showed that the composite system exhibited a more controllable swelling process and a more stable equilibrium swelling state, suggesting better structural durability and operational stability under moist wound conditions. Figure 1 (J).

[0079] The above results demonstrate that the EMPB functional layer possesses a stable porous microstructure, uniform composite characteristics, and enhanced network robustness. In particular, the denser pore wall morphology observed after the introduction of EGCG may contribute to maintaining network integrity under moist wound conditions, which is consistent with the improved mechanical robustness and more controllable swelling behavior of the composite hydrogel. These material properties lay the foundation for EMPB to achieve continuous adhesion in the moist wound microenvironment and for subsequent self-powered, electrically driven active drug delivery.

[0080] 2. Electrochemical performance of EMPB Iontophoresis relies on a stable DC electric field to drive electromigration and electroosmosis, thus being highly sensitive to output stability and interfacial impedance. To verify the feasibility and operational stability of key electrochemical functional layers in the EMPB system in terms of energy output and ion transport, we systematically characterized their electrochemical behavior, interfacial impedance, and cycle durability. First, the electronic conductivity of the electrodes was evaluated using linear sweep voltammetry (LSV). The hydrogel electrode without MXene showed almost no current response. In contrast, after MXene incorporation, the electrode current increased significantly linearly with the applied voltage, indicating a significant enhancement in electronic conductivity. Notably, further introduction of EGCG resulted in a significantly higher current response for the EMP hydrogel electrode compared to the MP control. Figure 2 (A). This performance improvement stems from the formation of a denser, more continuous conductive network induced by EGCG, which enhances electrochemical activity and charge transfer capabilities, providing a solid foundation for stable energy output.

[0081] To further elucidate the interfacial electrochemical processes, we used electrochemical impedance spectroscopy (EIS) to quantitatively compare charge transfer impedance and ion diffusion impedance. Figure 2 (BD). In the Nyquist plot, compared with MP and PVA hydrogel electrodes, EMP exhibits a significantly smaller semicircle and lower overall impedance, indicating reduced interfacial charge transfer impedance and improved ion transport. This behavior is attributed to its porous structure and interconnected three-dimensional network, which promotes efficient ion migration, minimizes energy loss, and improves operating efficiency. Figure 2 (B, C). Furthermore, at a frequency of 0.01 Hz, the interfacial impedance of both EMP and MP is significantly lower than that of the PVA hydrogel electrode, which is attributed to their superior conductivity and denser conductive network. Figure 2 (D).

[0082] Given that ion conduction is crucial for stable discharge behavior and ion introduction operation, we further measured the ionic conductivity of different hydrogels ( Figure 2 (E). The ionic conductivity of both EMP and MP was significantly higher than that of pure PVA, confirming that the introduction of MXene effectively improved the ion transport capacity of the hydrogel matrix. Although the ionic conductivity of EMP was slightly lower than that of MP, it was still significantly higher than that of pure PVA, indicating that the introduction of EGCG did not disrupt ion transport within the conductive hydrogel. This difference may be related to the formation of a relatively denser network after EGCG loading, while continuous hydrated ion conduction channels were still preserved.

[0083] To evaluate the energy storage capacity of the hydrogel, we conducted cyclic voltammetry (CV) tests under different kinetic conditions. Figure 2 Figure F shows the CV curves of the EMPB hydrogel electrode in PBS electrolyte at different scan rates within a voltage window of −0.4 V to 0.6 V. The EMPB hydrogel electrode exhibits a higher current density than the PVA hydrogel at all scan rates. At 5 mV·s -1 At the scan rate, the areal capacitance of EMPB reaches 14.62 mF·cm. -2 While PVA hydrogel has a strength of only 3.282 mF·cm⁻¹. -2 ( Figure 11 Furthermore, after 500 charge-discharge cycles, EMPB retained 98.14% of its initial capacitance, demonstrating excellent electrochemical stability. Figure 12 ).

[0084] We further evaluated the charge injection capability of the EMPB hydrogel electrode. Upon application of a 0.5 V pulse voltage, the electrode immediately generated a current response. Figure 2 (G). The EMPB hydrogel electrode can achieve a stimulation current density of up to 3.86 mA·cm. -2 The charge injection capacity (CIC) is 261 µC·cm. -2 After 500 stimulation cycles, the CIC remained at 96% of its initial value. Figure 2 The combination of high mixed conductivity, low interfacial impedance, and stable charge injection capability ensures efficient conversion of electron current into ion flux, thereby supporting effective ion delivery. Figure 10 The images show photographs of the electrode patch under electrochemical testing conditions and when applied to a rat wound model.

[0085] Furthermore, we provide a schematic diagram to illustrate the working mechanism of the zinc-based battery during discharge: electrons are transferred through an external circuit (load), while ions migrate in the electrolyte to maintain charge neutrality. This schematic diagram highlights the inherent coupling between self-powered output and ion transport in the EMPB system. Figure 2The assembled device exhibits stable open-circuit voltage and short-circuit current over time. Figure 2 The EMPB integrated zinc-ion battery exhibits load-dependent discharge behavior within a resistance range of 10–500 Ω (J, K). Notably, it can operate continuously for up to 650 min under a 10 Ω load. Figure 2 (L).

[0086] To visually evaluate the ability of EMPB to enhance mass transfer, we used dye molecules as model tracers and monitored their migration over time. Figure 2 (M, N). Under control conditions, the dye was mainly confined to the vicinity of the liquid surface, with limited downward diffusion. Even after 15 min, no significant homogenization was observed, suggesting low passive transport efficiency. Figure 2 In contrast, after applying EMPB, the dye penetrated rapidly, showing significant downward migration within 1 minute, and had extensively penetrated the entire medium by 5 minutes. Figure 2 Quantitative analysis further confirmed these observations: the cumulative release rate in the EMPB group increased rapidly, exceeding 50% within 2 minutes and approaching approximately 80% at 10 minutes; while the release curve in the control group was significantly slower, plateauing at approximately 40% within the same timeframe. Figure 2 (O). The dye molecule was chosen as the model tracer because its migration process is easy to visualize and quantify. Since the dye molecule is larger than EGCG, its transport is expected to be more difficult under the same conditions, thus serving as a conservative assessment of the active delivery capability of EMPB. Furthermore, the sodium alginate gel used in this dye tracing experiment provided a hydrated, ionicly conductive environment, which can partially simulate the moist wound interface, thereby enabling visualization of electric field-driven material transport. Therefore, the faster dye migration in the EMPB group further supports the active delivery capability of EMPB.

[0087] In traditional iontophoresis, the electrode and the hydrogel drug reservoir are physically separated, forming an additional interface between the two layers. At the electrode / drug reservoir interface, electron current must be converted into ion flux to drive the diffusion of therapeutic drugs via electrostatic repulsion. However, due to the high overpotential of the electrode, the charge transfer process often generates local heat, thereby reducing the overall efficiency of electrostimulation. Unlike traditional iontophoresis patches composed of separate electrode and drug reservoir layers, which suffer from severe energy dissipation due to interfacial impedance, our integrated EMPB structure maximizes local electric field efficiency. In this system, the EMP hydrogel simultaneously serves as the hydrogel electrolyte, conductive electrode, and drug reservoir, forming a continuous and tight interface between the electrode and the hydrogel components. This design avoids the microgaps, poor contacts, and interfacial discontinuities common in physically stacked devices. Furthermore, the continuous hydrogel network provides efficient pathways for ion and electron transport, reducing interfacial charge transfer impedance and battery internal resistance, thereby reducing energy loss during battery operation and electrically driven ion transport. As visually demonstrated by dye-tracing experiments, this strong electroosmotic driving force facilitates the shift from concentration-dependent passive diffusion to efficient active transport.

[0088] Iontophoresis is highly sensitive to the stability of an applied DC electric field, as output fluctuations directly translate into unstable electromigration or electroosmosis, leading to uncontrollable effective delivery dose. Against this backdrop, the EMPB offers a self-powered and highly stable drive module. It features stable open-circuit voltage and short-circuit current and can operate for extended periods under load (approximately 650 min at 10Ω), supporting long-term stable ion flux at the wound interface. Importantly, the power generation process is automatically activated by the moist wound microenvironment, with wound exudate acting as the electrolyte to initiate the Zn battery, achieving activation without external leads. In contrast, traditional iontophoresis devices are often limited by bulky external power supplies and poor wearability. This self-powered module effectively addresses these shortcomings, thereby improving the wearing comfort required for long-term RISI management.

[0089] 3. Biological effects of EMPB on HaCaT cells Biocompatibility is a fundamental requirement for hydrogel wound dressings because these materials need to be in close contact with the skin. Basal epidermal cells and keratinocytes are the main cellular targets in radiation-induced skin injury. Therefore, we first used HaCaT cells to evaluate the biocompatibility of the material. After culturing on MP, EMP, or EMPB for 3 days, live / dead staining showed that cell density continued to increase over time, and no significant accumulation of dead cells was observed. Figure 3 The result (A) indicates no cytotoxicity. CCK-8 results also showed that viable cell levels gradually increased from day 1 to day 3 in different groups, with no statistically significant difference between groups. Figure 3(Middle B). Therefore, CCK-8 and live / dead fluorescence staining results indicate that EMPB has good biocompatibility and no significant cytotoxicity ( Figure 3 (A, B). Furthermore, colony formation and survival were well preserved in the EMP and EMPB groups, suggesting that radiation-related growth inhibition was effectively alleviated. Figure 3 (D).

[0090] Compared to ordinary skin wounds, radiation-induced skin injuries heal more slowly and are more difficult to recover from because ionizing radiation not only causes vascular damage, tissue fibrosis, and immune dysfunction, but also leads to persistent inflammation, creating an unfavorable microenvironment that hinders effective repair. Furthermore, efficient wound repair depends on coordinated skin cell migration, and enhanced migration ability promotes healing. Therefore, we used a scratch assay to assess whether EMPB modulates HaCaT cell migration behavior. X-ray exposure significantly impaired cell migration, as evidenced by a significantly reduced proportion of migrated area at 24 h compared to the control group. Under radiation conditions, MP partially improved migration, while EMP further enhanced the migration response. Notably, EMPB showed the most significant enhancement of migration: at 24 h, the proportion of migrated area in the EMPB group exceeded that in the X-ray group and was still higher than that in the EMP group. Representative images also confirmed these results, showing more complete scratch closure in the EMPB group at 24 h, while the X-ray group showed the slowest closure. Figure 3 (C, E). Overall, these results indicate that EMPB can effectively rescue radiation-induced migration defects without compromising cellular safety, thereby supporting the cell migration process required for re-epithelialization. To further evaluate in vivo systemic biosafety, we collected major organs for histological examination. The results showed that no tissue damage or inflammatory infiltration was observed in the heart, liver, spleen, lungs, and kidneys under different treatments, suggesting that EMPB treatment did not cause systemic toxicity. Figure 3 (Middle F). In summary, EMPB can maintain HaCaT cell viability without cytotoxicity and effectively enhance cell migration after irradiation, demonstrating good biocompatibility and its potential to promote re-epithelialization in RISI repair.

[0091] 4. EMPB alleviates radiation-induced oxidative stress and ferroptosis. Ionizing radiation can directly damage cellular DNA and trigger the radiolysis of water molecules to generate free radicals, thereby further inducing oxidative stress. Excessive accumulation of reactive oxygen species (ROS) can lead to chronic oxidative stress, severely disrupting cellular homeostasis and thus hindering tissue regeneration. These damage signals and stress responses can trigger multiple cell death pathways, including apoptosis, necrosis / programmed necrosis, pyroptosis, and ferroptosis. Ferroptosis plays a central role in radiation damage by amplifying oxidative damage. Ionizing radiation promotes excessive ROS accumulation and increases free Fe²⁺. 2+Both EMP and EMPB disrupt iron homeostasis, making cells more susceptible to ferroptosis. To systematically evaluate the radioprotective effects of EMP and EMPB, we measured intracellular ROS and free Fe in HaCaT cells. 2+ GPX4 expression and γ-H2AX signaling were also observed. ROS levels were significantly increased after X-ray exposure compared to the control group. In contrast, MP, EMP, and EMPB treatments all significantly reduced intracellular ROS, with EMPB showing a more significant ROS scavenging effect than MP or EMP. Figure 4 (A, D) The FerroOrange probe was used to assess intracellular free Fe in HaCaT cells after X-ray irradiation. 2+ Pool. Figure 4 Figures B and E show that X-ray treatment induces Fe 2+ Pathological accumulation, and EMPB intervention can gradually alleviate this abnormal Fe. 2+ Overload. GPX4 is a key lipid hydroperoxidase that limits lipid peroxidation and is widely considered a core regulator of ferroptosis. Consistently, X-ray irradiation significantly reduced GPX4 protein expression in HaCaT cells, while EMP and EMPB treatments significantly restored GPX4 levels. Figure 4 (C, F). γ-H2AX staining revealed DNA breakage signals in HaCaT cells after different treatments. Compared with radiation alone, the fluorescence intensity of cells treated with EMP and EMPB was significantly reduced after radiation, suggesting that X-ray-induced DNA damage was alleviated. Figure 14 Overall, these results suggest that EMPB can alleviate radiation-related oxidative stress and ferroptosis-related phenotypes in keratinocytes.

[0092] Ionizing radiation is known to drive excessive ROS production, and this redox imbalance is considered a significant factor in the occurrence and exacerbation of radiation-induced skin damage. Excessive ROS accumulation leads to widespread, non-selective oxidative damage to the intracellular proteome, lipids, and nucleic acids, inducing apoptosis, DNA strand breaks, and tissue necrosis. However, physiological levels of ROS are equally important for regulating cell communication, proliferation, and tissue repair. Wei et al. reported a hydrogel spray integrating a multifunctional nanozyme with SOD / CAT-like cascade catalytic activity, which scavenges excess ROS and generates oxygen, thereby correcting oxidative stress and hypoxia in the microenvironment of diabetic wounds, promoting M1-to-M2 macrophage repolarization and angiogenesis, and ultimately accelerating the healing of full-thickness skin wounds and refractory foot ulcers in diabetic rats. Kang et al. developed a smart bilayer hydrogel that can adaptively and programmatically regulate ROS in stages. In the early, susceptible stage, the inner layer detects bacterial-associated hyaluronidase and triggers a strong ROS burst under light irradiation to kill bacteria; subsequently, the outer layer continuously scavenges ROS to alleviate oxidative stress, thereby promoting inflammation resolution, angiogenesis, and burn tissue regeneration. Therefore, maintaining ROS homeostasis is crucial for mitigating radiation-induced damage and promoting effective skin regeneration. The EMPB developed in this study can directly reduce ROS by actively releasing EGCG, thereby helping to establish a balanced redox microenvironment supporting RISI tissue regeneration.

[0093] Subsequently, we quantitatively detected key ferroptosis-related biomarkers, including GPX4, SLC7A11, ACSL4, and NADPH oxidase 1 (NOX1), to explore the mechanism by which EMPB alleviates radiation-induced ferroptosis in HaCaT cells. X-ray irradiation severely disrupts the anti-ferroptosis defense system by inhibiting GPX4 and SLC7A11 transcription, while simultaneously inducing the expression of pro-ferroptosis drivers such as ACSL4 and NOX1. Both EMP and EMPB significantly increased GPX4 and SLC7A11 mRNA levels and decreased ACSL4 and NOX1 mRNA levels, indicating that the ferroptosis program was inhibited. Figure 5 (AD). Notably, compared with MP and EMP, EMPB significantly restored GPX4 and SLC7A11 expression. Mitochondria are organelles responsible for ATP production and are key structures regulating cellular redox homeostasis and oxidative stress. During ferroptosis, significant mitochondrial shrinkage, characterized by increased membrane density and loss of mitochondrial cristae, is observed, jointly indicating severe organelle dysfunction. To validate the ferroptosis phenotype at the ultrastructural level, we used transmission electron microscopy (TEM) to observe mitochondrial morphology (AD). Figure 5(E). Compared with the control group, the X-ray group showed ferroptosis-related changes in mitochondria, including reduced mitochondrial volume, loss or reduction of cristae, and increased membrane density. EMP significantly alleviated these abnormalities, while EMPB was even more effective, showing more intact mitochondrial structure and clearer cristae, suggesting that it can protect cells from radiation-induced ferroptosis-related mitochondrial damage.

[0094] NRF2 has become an important focus in recent years in the study of ferroptosis regulation. Under basal conditions, NRF2 is fixed in the cytoplasm by KEAP1; upon activation, NRF2 dissociates from KEAP1 and translocates into the nucleus, upregulating transcriptional programs that enhance antioxidant defense and suppress inflammatory signaling. Furthermore, Western blot analysis showed that X-ray irradiation decreased the protein levels of NRF2, SLC7A11, and GPX4, while EMP / EMPB significantly restored key components of this pathway, with the EMPB group showing the most significant upregulation. Figure 5 (FI).

[0095] Based on these results, the stronger biological effects of EMPB compared to EMP may be related to the combined effects of enhanced EGCG delivery and autogenous electrical stimulation. EMP primarily relies on the passive release of EGCG, while EMPB introduces a micro-electric field activated by wound exudate. This micro-electric field can both promote electroosmotic-mediated EGCG transport and provide electrical stimulation. Therefore, EMPB not only improves the local accessibility of EGCG but may also promote cell migration through bioelectrical signals. These effects collectively explain why EMPB exhibits stronger pro-migration and anti-ferroptosis effects than EMP in vitro. Active delivery helps maintain sufficient local therapeutic concentrations at the site of radiation injury, thereby conferring stronger anti-ferroptosis capabilities. Mechanistically, EMPB enhances the NRF2 / SLC7A11 / GPX4 antioxidant axis, restores the reduced expression of anti-ferroptosis markers (GPX4 and SLC7A11), inhibits ferroptosis pro-factors (ACSL4 and NOX1), reduces radiation-induced ROS accumulation, and limits Fe. 2+ Accumulation, thereby helping to maintain mitochondrial functional homeostasis under radiation stress.

[0096] 5. EMPB accelerates RISI wound healing and improves tissue remodeling. After confirming that EMPB can inhibit ferroptosis, protect DNA from damage, and promote cell migration in vitro, we established a rat RISI model to further investigate the effects of MP, EMP, and EMPB on RISI. Figure 6 (A). Different materials were applied starting at specified time points, and the wound appearance was recorded on days 1, 3, 7, and 14. Tissue samples were collected on day 14 for histological analysis. Figure 6(A). No abnormal treatment-related weight loss was observed in the irradiation group, although their weight remained lower than that of the non-irradiated control group ( ). Figure 6 (B)

[0097] like Figure 6 As shown in Figure A, the skin wound on the back of rats was irradiated with 30 Gy X-rays. Following irradiation, MP, EMP, and EMPB were locally applied to the affected skin area and changed every two days. In addition to the pharmacological intervention of EGCG, the in-situ electrical stimulation (ES) provided by the EMPB patch may have acted as a physical driver, accelerating wound healing in the RISI model. Wound progress was photographed and recorded on days 1, 3, 7, and 14. Figure 6 (C) Mild erythema was observed after irradiation. With prolonged treatment, wound healing was slow in the X-ray group, failing to fully close even by day 14. In contrast, wounds treated with EMPB showed near-complete healing by day 14, with better skin regeneration. Overall, these observations demonstrate that EMPB accelerates wound healing and enhances tissue regeneration compared to other treatments, proving its effectiveness in promoting RISI healing.

[0098] To further evaluate the quality of tissue regeneration and remodeling, we collected wound tissue on day 14 and performed hematoxylin-eosin (H&E) staining and Masson's trichrome staining. Results showed that 14 days after treatment, the EMP and EMPB groups had more intact skin structure and reduced inflammatory cell infiltration. Figure 6 (E). Notably, the EMPB group showed a higher degree of tissue repair than the EMP group. In contrast, the X-ray and MP groups showed significant parakeratosis and marked inflammatory infiltration, indicating incomplete healing. Masson staining revealed increased collagen deposition and a more dense and orderly arrangement of collagen fibers in the EMPB group. Figure 6 (In the EG). These results support the superior repair effect of EMPB, which may be attributed to its ability to clear radiation-induced excess ROS accumulation, ferroptosis, and local inflammation.

[0099] To determine whether the improvement in gross wound closure and histological recovery was mechanistically related to ferroptosis regulation, we further examined GPX4 expression in vivo. Immunohistochemical staining showed that GPX4 levels were significantly restored in the EMPB group, consistent with in vitro results, suggesting that the local anti-ferroptosis defense system in irradiated skin tissue was enhanced. Figure 7 (A, C)

[0100] Normal wound repair unfolds in an orderly process, including hemostasis and inflammatory response, followed by the proliferative and remodeling phases. This cascade process is driven by coordinated cell migration and growth, extracellular matrix formation, and gradual tissue reorganization. Angiogenesis is central to the proliferative phase and supports subsequent extracellular matrix remodeling and skin regeneration. Therefore, we used CD31 staining to evaluate angiogenesis in the damaged area. Radiation-induced lipid peroxidation and iron homeostasis disturbances can trigger endothelial cell ferroptosis, leading to impaired microvascular barrier and restricted revascularization. Therefore, inhibiting ferroptosis may improve local perfusion and promote angiogenesis. Consistent with this inference, neovascularization signals were minimal in the X-ray and MP groups, while CD31-positive staining was most pronounced in the EMPB group. Figure 7 (A, B). Given that EMPB has been shown to have anti-ferroptosis effects, these results suggest that EMPB may enhance angiogenesis, possibly by alleviating ferroptosis-related microvascular dysfunction in irradiated tissues.

[0101] Ionizing radiation damages cells, prompting them to produce inflammatory mediators and recruit immune cells to the wound. The recruited cells then release cytokines and chemokines, thereby exacerbating the inflammatory response. Multiple cytokines jointly regulate the healing process, but the abnormal release of key pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) can maintain chronic inflammation and severely impair tissue regeneration. Furthermore, the production of ROS can further stimulate the secretion of pro-inflammatory cytokines. Therefore, we further assessed the expression of TNF-α, IL-1β, IL-6, and ROS in the wounds of different treatment groups using immunofluorescence. Compared with the X-ray and MP groups, the EMP and EMPB groups showed lower levels of TNF-α, IL-1β, IL-6, and ROS. Figure 7 (Middle DH). The expression of TNF-α, IL-1β, IL-6, and ROS was inhibited in the EMPB group, indicating that EMPB can effectively reduce wound inflammation and oxidative stress, thereby promoting RISI tissue repair. Combined with its ability to reduce the burden of pro-inflammatory cytokines, EMPB may alleviate ferroptosis-related injury and promote inflammation resolution.

[0102] In the complex microenvironment of the rat RISI model, wound exudate may limit the penetration of passively released drugs, as evidenced by the delayed healing observed in the EMP group. Notably, the EMPB system overcomes this significant barrier. Driven by a self-powered electric field, EGCG can be delivered more efficiently to the irradiated wound area, thereby more effectively modulating the pathological microenvironment and reducing ferroptosis, oxidative stress, and inflammation.

[0103] The reduction in ferroptosis and inflammation may be attributed to EGCG release, which can alleviate the downstream inflammatory cascade driven by ROS and ferroptosis. Ferroptosis was first discovered by Dixon et al., who demonstrated that erastin can induce an atypical, iron-dependent, non-apoptotic form of cell death. Besides cancer, dysregulation of ferroptosis is also thought to be involved in various pathological conditions, including impaired wound repair. Studies suggest that inhibiting ferroptosis under various pathological conditions may help improve tissue repair and wound healing.

[0104] In summary, the therapeutic effect of EMPB in RISI models is related to its anti-ferroptosis activity. By restoring GPX4 expression, the patch can alleviate oxidative damage and chronic inflammation, thereby supporting vascular remodeling and extracellular matrix reconstruction during RISI repair.

[0105] 6. Mechanism by which EMPB promotes RISI regeneration To elucidate the molecular basis of EMPB's role in promoting RISI repair in vivo, we performed RNA sequencing (RNA-seq) on skin tissues from the EMPB-treated group and the X-ray group. (Volcano diagram) Figure 8 The results (B) showed that 1236 genes were upregulated and 951 genes were downregulated (|log2FC| ≥ 1, P < 0.05), suggesting that EMPB treatment induced extensive transcriptome remodeling. The heatmap further illustrated the expression patterns of representative differentially expressed genes (DEGs) and showed a clear separation between the two groups, especially in stress-related gene clusters. Figure 8 (A)

[0106] Notably, EMPB significantly modulated the core molecular axis connecting oxidative stress, iron homeostasis, and ferroptosis. Compared to the X-ray group, the EMPB group showed upregulation of GPX4 and SLC7A11, while downregulation of the key ferroptosis-promoting lipid metabolism regulator ACSL4. Figure 8 (A). This transcriptional signature suggests that EMPB can enhance glutathione-dependent lipid peroxide clearance and reduce ferroptosis susceptibility, thereby providing a more favorable redox environment for post-radiation tissue regeneration.

[0107] KEGG and GO results showed that DEGs significantly accumulated in pathways related to ferroptosis, inflammatory responses, cytokine signaling, ECM-receptor interactions and cell adhesion, matrix remodeling, and angiogenesis. Figure 8(E, F). These results suggest that EMPB intervention may synergistically regulate multiple key repair modules, including inflammation resolution, extracellular matrix remodeling, and tissue perfusion restoration. DEG-based enrichment analysis further supports these observations. Furthermore, gene set enrichment analysis (GSEA) showed that pathways such as ferroptosis and cytokine-cytokine receptor interactions were enriched in the X-ray group and showed an inhibitory trend in the EMPB group. Figure 8 (C, D) suggests that EMPB may suppress radiation-triggered ferroptosis and inflammation-related transcriptional programs. These pathway-level changes are consistent with differential expression of key regulators, including upregulation of GPX4 and SLC7A11 and downregulation of ACSL4.

[0108] Regarding angiogenesis-related signals, GSEA indicated that VEGF signal showed an increasing trend in the EMPB group. Figure 15 Although no statistically significant enrichment was observed (P>0.05), this trend was consistent with enhanced CD31 positivity at the tissue level. Figure 7 (A). These findings suggest that EMPB may support angiogenesis-related responses and promote the recovery of the microvascular network in irradiated skin. Given that radiation-induced microvascular damage and the resulting local hypoperfusion are key pathological features of RISI, this vascular improvement may be an important component of the repair process. We further hypothesize that EMPB, through electroosmotic-driven EGCG delivery, may alleviate lipid peroxidation and ferroptosis within the wound bed, thereby helping to maintain vascular integrity under oxidative stress and creating a microenvironment more conducive to angiogenesis-related signaling. These effects may link the inhibition of ferroptosis damage with improved microcirculatory status, ultimately promoting accelerated tissue remodeling during RISI repair.

[0109] Overall, RNA-seq analysis revealed that EMPB supports RISI repair by coordinating the regulation of key genes and pathways, characterized by the suppression of ferroptosis and inflammation while promoting angiogenesis-related processes. Importantly, this synergistic inhibition of ferroptosis may be related to the integrated design of EMPB. This system utilizes an electrically driven transport process in which electroosmotic flow promotes the active delivery of EGCG to the irradiated wound bed. These transcriptomic insights provide a molecular explanation for the therapeutic effect of EMPB in accelerating RISI wound closure and tissue regeneration in vivo.

[0110] 7. Conclusion This invention integrates a flexible Zn-based battery with a conductive EMP hydrogel to construct a wound exudate-activated iontophoresis delivery platform, namely an EGCG-loaded self-powered hydrogel bioelectronic patch. Without the need for an external power source, the EMPB generates a stable micro-electric field upon contact with the moist wound environment, enabling a shift in EGCG delivery from passive diffusion to electrically assisted active delivery. Figure 9In in vitro experiments, EMPB promoted keratinocyte migration, reduced oxidative stress, and inhibited radiation-induced ferroptosis, which was associated with the restoration of the NRF2 / SLC7A11 / GPX4 antioxidant axis. In in vivo experiments, EMPB reduced local oxidative stress and inflammation, enhanced angiogenesis and collagen remodeling, and accelerated the repair of irradiated skin wounds. These results suggest that EMPB is a promising bioelectronic platform for the treatment of radiation-induced skin injuries.

[0111] Comparative Example 1 Electrode patches were prepared according to the method in Example 1, except that only pure PVA hydrogel was used. The results showed that while pure PVA hydrogel was relatively easy to gel and had some liquid absorption capacity, the material was almost non-conductive. Therefore, it was difficult to form a stable micro-electric field. Furthermore, pure PVA exhibited significant swelling, with a swelling rate as high as 1200% after 24 hours. It easily softened and became loose at the edges after wetting, making it unsuitable as a conductive patch for long-term adhesion and stable drug delivery.

[0112] Comparative Example 2 Electrode patches were prepared according to the method in Example 1, except that only EGCG and PVA were used to prepare the hydrogel, without the addition of MXene. The results showed that although the hydrogel could achieve drug loading, it was essentially a passive release process without a continuous conductive network. The ionic conductivity of this system was less than 0.05 S / m; the swelling rate after 24 h was 1000%. Regarding drug release, the cumulative release rate of this system in 10 min was only 45%, close to the level of ordinary passive release, far below the nearly 80% release efficiency of EMPB.

[0113] Comparative Example 3 Electrode patches were prepared according to the method in Example 1, except that an MXene / PVA conductive electrode layer and an EGCG / PVA drug-loaded hydrogel layer were stacked together to form a bilayer ion-introduction patch. Results showed that this method suffered from unstable interlayer contact, high interfacial impedance, and significant energy loss. Under the same conditions, the effective current response of the bilayer ion-introduction patch was 2.0 mA / cm², significantly lower than the 3.86 mA / cm² of EMPB; the charge injection capacity was 150 μC / cm², also significantly lower than the 261 μC / cm² of EMPB. In the drug release experiment, the release rate at 10 min was 60%, slightly better than passive release alone, but still inferior to the integrated EMPB system. Furthermore, this system was prone to interlayer slippage or localized separation after wetting.

[0114] Comparative Example 4 Electrode patches were prepared according to the method in Example 1, with MXene replacement ratios of 0.05 wt% and 0.2 wt%, respectively. The results showed that when the MXene content was too low (0.05 wt%), the conductive network was insufficient, with an ionic conductivity of only 0.35 S / m and a swelling ratio of 850%. When the MXene content was too high (0.2 wt%), although the conductivity was close to the final system, the material became less uniform, prone to lamellar aggregation, localized deposition, and wet brittleness. The tensile strength actually decreased to 120 kPa, lower than the 240 kPa level of the final EMP hydrogel. Therefore, simply increasing or decreasing MXene cannot simultaneously achieve good conductivity, flexibility, and structural stability.

[0115] Comparative Example 5 Electrode patches were prepared according to the method in Example 1, except that EGCG was replaced with vitamin C or ferulic acid. The results showed that the stability and release controllability of the two substituted drugs in the hydrogel were inferior to EGCG. Vitamin C retained less than 50% of its content in simulated wound exudate after 24 h, and the release rate of the ferulic acid system was only 55% after 10 min. More importantly, neither of these drugs possessed the property of improving the mechanical and electrochemical properties of the hydrogel, thus failing to achieve the corresponding effects of this invention.

[0116] In summary, the EMPB iontophoresis patch of this invention is not simply a combination of "conductive material + drug". The addition of EGCG resulted in more intact and denser pore walls in the hydrogel, and improved tensile strength and toughness – a development that exceeded expectations. Furthermore, based on infrared, Raman, and XPS results, EGCG likely participates in stabilizing the hydrogel network through hydrogen bonding with PVA and MXene via its phenolic hydroxyl groups, rather than being simply embedded within the material.

[0117] On the other hand, electrochemical results show that the addition of EGCG did not weaken the conductivity of the material. On the contrary, the EMP hydrogel exhibited lower interfacial impedance, better current response, and improved ion transport capabilities. This may be related to EGCG improving the dispersion of MXene sheets and reducing sheet aggregation. In other words, EGCG in this system is not only a therapeutic component but also plays a positive role in regulating the material network and interfacial electrochemical properties.

[0118] However, EGCG is easily diluted by wound exudate when applied topically, making it difficult to maintain a local effective concentration. Furthermore, traditional iontophoresis devices require an external power source, have a complex structure, and are not suitable for long-term application to wounds. Therefore, in the composite patch system of this invention, EGCG, MXene / PVA hydrogel, and the self-powered structure form a mutually reinforcing relationship, improving both the material structure and the electrochemical performance and drug delivery efficiency.

Claims

1. A method for preparing an integrated zinc battery-driven iontophoresis patch, characterized in that, Includes the following steps: (1) MXene nanosheets were dispersed in water to obtain an MXene dispersion; (2) The MXene dispersion obtained in step (1) is mixed with polyvinyl alcohol and stirred at high temperature to prepare a PVA / MXene composite solution; (3) Add EGCG to the PVA / MXene composite solution obtained in step (2), and the mixture is subjected to freeze-thaw cycles to form a composite hydrogel; (4) Using the composite hydrogel obtained in step (3) as the cathode of the battery, Zn foil as the anode, and PBS as the electrolyte, a zinc-ion hydrogel battery is assembled to prepare an integrated zinc battery-driven ion-importing patch.

2. The method according to claim 1, characterized in that, The method for preparing MXene nanosheets is as follows: Ti3AlC2 powder is slowly added to a mixture of LiF and HCl, stirred at 35°C for 24 h, the resulting product is centrifuged and washed, the supernatant is collected and freeze-dried for 24 h to obtain MXene nanosheets.

3. The method according to claim 1, characterized in that, In step (2), the weight ratio of MXene dispersion to polyvinyl alcohol is 1:

100.

4. The method according to claim 1, characterized in that, The conditions for the stirring reaction in step (2) are: stirring at 95°C and 600 rpm for 5 h.

5. The method according to claim 4, characterized in that, The amount of EGCG used in step (3) is 0.01-0.1 wt%.

6. The method according to claim 1, characterized in that, In step (3), the freeze-thaw cycle is repeated three times, and the conditions for each freeze-thaw cycle are -20℃ for 4 hours.

7. An integrated zinc battery-driven iontophoresis patch prepared by the method of any one of claims 1-6.

8. The use of the integrated zinc battery-driven iontophoresis patch of claim 7 in the preparation of medicaments or medical devices for treating radiation-induced skin damage.

9. The use of the integrated zinc battery-driven iontophoresis patch of claim 7 in the preparation of a medicament for treating ferroptosis inhibitors.

10. The use of the integrated zinc battery-driven iontophoresis patch of claim 7 in the fabrication of a wearable device for treating radiation-induced skin damage.

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