Composition for skin wound regeneration and repair as well as preparation method and application thereof

Abstract

The invention discloses a composition for skin wound regeneration and repair and a preparation method and application thereof. A monatomic transition metal modified photocatalytic material is constructed, selective oxidation and inactivation of a damage-related molecular mode are realized, and a mediated inflammation signal channel is accurately inhibited, so that the immune homeostasis of a wound part is reconstructed, and tissue repair is promoted. Through monatomic active site construction, electronic structure regulation and control and photon-generated carrier behavior optimization, the photocatalytic material can stably generate selective oxidation capacity under the physiological illumination condition, and the continuous functions of anti-inflammation and tissue regeneration are achieved.

Description

Technical Field

[0001] This invention belongs to the field of biomedical photocatalytic materials technology, and in particular relates to a composition for skin wound regeneration and repair, its preparation method and application. Background Technology

[0002] Following skin injury, the body initiates an immune response that triggers a surge of reactive oxygen species (ROS) and the efflux of damage-associated molecular patterns (DAMPs) such as HMGB1 and ATP, activating a cascade of inflammation mediated by key signaling chains such as TLR4 / RAGE-STAT1. Imbalance in this process can lead to excessive inflammation, exacerbated cell damage, delayed matrix reconstruction, and scar hyperplasia. Existing anti-inflammatory materials primarily focus on ROS clearance or cell protection, but lack the ability to precisely regulate key DAMPs, making it difficult to interrupt the inflammatory cascade at its source.

[0003] To address the problem of excessive inflammatory activation during skin wound repair, current technical approaches mainly include the following categories: (1) Antioxidant materials or hydrogels, such as those rich in phenolic hydroxyl groups, selenium / cerium-based nanoparticles, and metal-organic frameworks (MOFs), which alleviate inflammatory damage by scavenging ROS; (2) Anti-inflammatory drug release systems, such as nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and anti-inflammatory factors like IL-10, which are released in a controlled manner by microspheres, hydrogels, or nanocarriers to inhibit inflammatory mediators; (3) Traditional g-C3N4 or TiO2 photocatalytic materials, which utilize photogenerated carriers to generate specific oxides / free radicals to assist repair through antibacterial or non-specific oxidation; (4) Macrophage immunomodulatory materials, such as peptides that promote M2 phenotypic polarization, chitosan, and Mg 2+ Or specific extracellular matrix materials, which promote repair through immune regulation.

[0004] Although the above techniques have achieved some success in reducing inflammatory responses, they still have the following key shortcomings: a. Difficulty in achieving specific regulation of key damage-related molecular patterns: The core mechanisms of action of existing anti-inflammatory or photocatalytic materials are mostly focused on non-specific reactive oxygen species scavenging or broad-spectrum oxidation reactions. While these methods can alleviate excessive inflammatory responses to some extent, they lack the ability to precisely regulate damage-related molecular patterns such as HMGB1, thus failing to effectively intervene at the source of inflammatory signaling. Especially during the immune initiation phase of skin trauma, the release of DAMPs is a crucial step in triggering the activation of key signaling chains such as TLR4 / RAGE and subsequent cascade reactions. Traditional technologies cannot block this important starting point through selective oxidation or inactivation, resulting in the continued amplification of the inflammatory response and making it difficult to achieve true inflammatory rebalancing. Because the continuous efflux of DAMPs cannot be controlled, current technologies lack the ability to fundamentally regulate the post-injury immune environment.

[0005] b. Traditional photocatalytic materials are difficult to meet the requirements for in vivo applications: Photocatalytic materials, such as g-C3N4 and TiO2, generally exhibit insufficient catalytic efficiency in low-light, physiologically sensitive, and neutral water environments. Their photogenerated electrons and holes are prone to recombination, resulting in limited visible light absorption. Furthermore, the lack of atomically precise structural design at their effective active sites makes it difficult to maintain sustained and controllable catalytic activity under the low-light conditions commonly found in wound tissues. Even with relevant modification strategies, most efforts focus on improving spectral response or adjusting local electronic structure, failing to significantly improve catalytic performance in biological environments. Therefore, existing photocatalytic materials struggle to achieve selective responses to biomolecules through precise photogenerated carrier management, and are unable to exert stable anti-inflammatory and pro-repair functions in the complex tissue microenvironment. Insufficient material activity leads to instability in in vivo applications, limiting their practical therapeutic effects.

[0006] c. Insufficient depth of regulation of the inflammatory signaling network, failing to achieve continuous inhibition from upstream to downstream: Current anti-inflammatory strategies, whether through drug release, antioxidant free radical scavenging, or macrophage polarization induction using immunomodulatory materials, are mostly limited to local stages of inflammation or single molecular pathways, lacking the ability to inhibit key signaling chains such as HMGB1-TLR4 / RAGE-STAT1. Because they cannot simultaneously intervene in key nodes such as inflammation initiation, signal transduction, and transcriptional regulation, upstream DAMPs release persists, and downstream chemokines such as CXCL10, CCR2, and CCR5 can still activate inflammatory cell migration and aggregation, making it difficult to comprehensively control the amplified inflammatory effect. The lack of multi-level signaling pathway intervention means that many existing materials can only exert partial effects at a certain stage of inflammation, failing to achieve a complete, chain-like immunomodulatory process, thus limiting their overall efficacy in promoting tissue regeneration.

[0007] d. The anti-inflammatory effect cannot effectively connect with the tissue repair process, resulting in limited overall regeneration quality: Many traditional anti-inflammatory or healing-promoting materials often treat inflammation control and tissue repair as two independent processes. Functionally, they often have some effect on inhibiting inflammation, but they struggle to simultaneously promote key aspects of wound healing such as fibroblast migration, endothelial cell angiogenesis, and collagen matrix remodeling, resulting in limited tissue regeneration. Due to the lack of continuous support for different stages of wound healing, while these materials can temporarily improve the local microenvironment in practical applications, they cannot synergistically enhance overall repair quality from multiple dimensions, including immune balance, angiogenesis, and new tissue construction. Therefore, existing technologies cannot meet the complete biological requirements of "rapidly reducing inflammation - promoting angiogenesis - improving collagen reconstruction quality," limiting their effectiveness in complex wounds.

[0008] In summary, existing photocatalytic materials struggle to achieve selective oxidation of DAMPs and effective intervention in key signaling chains such as HMGB1-TLR4 / RAGE under in vivo conditions. They cannot fundamentally block the inflammatory cascade or establish continuous regulation of the entire wound healing process, resulting in significant overall functional deficiencies. Furthermore, traditional photocatalysts suffer from poor selectivity, weak biosafety, and difficulty in achieving deep in vivo anti-inflammatory effects. Therefore, there is an urgent need to develop a highly selective and controllable photocatalytic immunomodulatory material for use in tissue regenerative medicine. Summary of the Invention

[0009] To address at least some of the technical problems in the prior art, this invention constructs a carbon nitride photocatalytic material regulated by a single-atom transition metal, achieving precise inactivation of inflammation-initiating molecules and comprehensive regulation of downstream signals. The photocatalytic material of this invention can rebalance the inflammatory microenvironment and promote skin wound regeneration and repair, thus fundamentally overcoming the limitations of traditional materials in immune regulation and repair promotion. Specifically, this invention includes the following:

[0010] A first aspect of the present invention provides a composition for skin wound regeneration and repair, the composition comprising a photocatalytic material, wherein the photocatalytic material comprises a graphitic carbon nitride matrix and a single-atom transition metal, the single-atom transition metal forming an AN with the graphitic carbon nitride matrix. x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

[0011] In some embodiments, the composition for skin wound regeneration and repair according to the present invention includes at least one of manganese, iron, cobalt and nickel.

[0012] In some embodiments, the composition for skin wound regeneration and repair according to the present invention further comprises a pharmaceutically acceptable carrier.

[0013] In some embodiments, the composition for skin wound regeneration and repair according to the present invention includes, wherein the pharmaceutically acceptable carrier comprises at least one of a diluent, a humectant, a preservative, and an antioxidant.

[0014] A second aspect of the present invention provides a method for preparing a photocatalytic material for skin wound regeneration and repair, comprising the following steps: (1) A graphitic carbon nitride matrix is ​​dispersed in an aqueous solvent to obtain a suspension; (2) The suspension is mixed with a transition metal salt solution and an organic solvent to carry out a coordination reaction to obtain a single-atom transition metal modified photocatalytic material, wherein the single-atom transition metal forms an AN with the graphite-phase carbon nitride matrix. x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

[0015] In some embodiments, according to the preparation method of the present invention, the preparation further includes surface treatment of the graphitic carbon nitride matrix prior to dispersion.

[0016] In some embodiments, according to the preparation method of the present invention, the transition metal salt includes at least one selected from nitrate, acetate, sulfate and acetylacetone.

[0017] In some embodiments, according to the preparation method of the present invention, the conditions for the coordination reaction include: a reaction temperature of 40-80°C and a reaction time of 1-10 h.

[0018] A third aspect of the present invention provides the application of the photocatalytic material described herein in the preparation of repair products for skin wound regeneration.

[0019] A fourth aspect of the present invention provides a method for selectively photocatalytically oxidizing or inactivating high-mobility group group B1 in cells, comprising the step of contacting cells in vitro with a photocatalytic material according to the present invention.

[0020] The present invention has the following technical effects: (1) Precise control of electronic structure: This invention constructs a stable AN in the g-C3N4 framework x The single-atom coordination structure enables precise control over the material's band structure and local electronic environment, significantly broadening the visible light response range and fundamentally improving the light absorption and photogenerated electron excitation capabilities.

[0021] (2) High efficiency of photogenerated carrier separation: The introduction of single-atom transition metal significantly enhances the separation efficiency of photogenerated electrons and holes. The transient photocurrent is 3-5 times that of CN, the charge migration rate is accelerated, the recombination probability is greatly reduced, and the carrier transport efficiency that traditional CN cannot achieve is realized.

[0022] (3) Excellent single-atom catalytic center construction effect: Through the coordination of atomic-level anchoring sites with transition metals, the formation of metal clusters or nanoparticles is avoided, maximizing the exposure of catalytic active sites and significantly improving the actual activity of catalyst per unit mass. This is an important structural breakthrough in the field of single-atom catalysis.

[0023] (4) The reaction energy barrier is significantly reduced: DFT calculations reveal that the photocatalytic material of the present invention has a lower free energy barrier (from +0.3 eV to -0.04 eV) during the activation of aromatic substrate CH and the generation of peroxide intermediates, thereby endowing it with the advantages of high activity and high selectivity in photocatalysis.

[0024] (5) Significantly improves the oxidation efficiency and selectivity of aromatic molecules: The photocatalytic material of the present invention can achieve highly efficient and selective oxidation of aromatic substrates such as toluene under visible light conditions, with the product generation amount being 4-6 times that of CN, significantly reducing over-oxidation and side reactions.

[0025] (6) The preparation process is standardized and scalable: The thermal polymerization-protonation-wet chemical anchoring technology route proposed in this invention is simple, stable and highly repeatable, and can achieve large-scale production. It also has the characteristics of high compatibility with existing chemical processes and controllable cost. Attached Figure Description

[0026] Figure 1 The transmission electron microscopy and high-resolution electron microscopy characterization results of Mn-CN of the present invention are shown.

[0027] Figure 2 The XRD and FITR results of Mn-CN of the present invention are shown.

[0028] Figure 3 XPS plot of Mn-CN of the present invention is shown.

[0029] Figure 4 The transient photocurrent (TPC) measurement results of the Mn-CN of the present invention are shown.

[0030] Figure 5 The oxidation activity of different Mn-CN materials under visible light irradiation is shown.

[0031] Figure 6 The DOS calculation results of Mn-CN and control materials of the present invention are shown.

[0032] Figure 7 The results of the adsorption energy and differential charge (CDD) analysis are shown.

[0033] Figure 8 The immunofluorescence results of the selective catalytic oxidation of HMGB1 by Mn-CN according to the present invention are shown.

[0034] Figure 9 The effects of the Mn-CN and control materials of the present invention on skin regeneration and repair are shown. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0038] In this invention, the terms "wound" and "excavation" or "injury" are used interchangeably, and include any damage or breakage of the epidermis or mucous membrane caused by any reason, including chronic wounds such as ulcers of various causes, as well as acute wounds, especially open wounds, examples of which include, but are not limited to, cuts, scratches, abrasions, lacerations, avulsions, punctures, excision wounds, infected wounds, ischemic wounds, radiation poisoning wounds, surgical wounds, or burns (e.g., thermal burns, chemical burns, radiation burns, etc.).

[0039] Composition In one aspect, the present invention provides a composition for skin wound regeneration and repair, the composition comprising a photocatalytic material, wherein the photocatalytic material comprises a graphitic carbon nitride matrix and a single-atom transition metal, the single-atom transition metal forming an A-Nx coordination structure with the graphitic carbon nitride matrix, where A is a transition metal element and x is an integer greater than 1. The transition metal is not particularly limited, and examples include, but are not limited to, manganese, iron, cobalt, and nickel.

[0040] Those skilled in the art will understand that, although some metals can also form single-atom -N x The coordination structure is different, but the positions of its d orbital energy levels and electron distributions are different. Therefore, the effects of effectively reducing the band gap of CN to the visible light range and significantly reducing the free energy barrier of the rate-limiting step of the reaction are different. Some metals can improve light absorption, but they are not strong enough for electron coupling to activate CH. Therefore, in a preferred embodiment, the transition metal mentioned in this invention is manganese.

[0041] The photocatalytic material of this invention can generate electron-hole pairs through photocatalysis, thereby oxidizing and inactivating specific organic molecules (damage-related molecular patterns), precisely inhibiting their mediated inflammatory signaling pathways, thus restoring the immune homeostasis at the site of injury, improving the inflammatory or infectious environment, and promoting skin wound regeneration and repair. Examples of organic molecules involved in the damage-related molecular patterns include, but are not limited to, high-mobility group box 1 (HMP-B1), adenosine triphosphate (ATP), heat shock proteins, and calcium-binding proteins.

[0042] This invention enables photocatalytic materials to stably generate selective oxidation capacity under physiological light conditions by constructing single-atom active sites, regulating electronic structure, and optimizing photogenerated carrier behavior, thereby achieving continuous anti-inflammatory and tissue regeneration functions.

[0043] In this invention, the doping amount of the transition metal can be controlled within a suitable range, thereby achieving excellent catalytic performance of the photocatalytic material (including but not limited to light absorption and photogenerated electron excitation performance, photogenerated electron-hole separation efficiency, maximum exposure of catalytic active sites, significantly reduced reaction energy barrier, selective catalytic oxidation activity, etc.) and skin wound regeneration and repair performance. In the photocatalytic material of this invention, the doping amount of the transition metal is 0.5-10%, preferably 0.5-9%, even more preferably 0.5-8%, further preferably 0.5-7%, more preferably 0.5-6%, more preferably 1-5%, for example 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5%.

[0044] In a preferred embodiment, the composition of the present invention further comprises a pharmaceutically acceptable carrier, each carrier being "acceptable" meaning that it is compatible with other components of the formulation (e.g., the photocatalytic material described in this invention) and does not harm the patient. The pharmaceutically acceptable carrier includes, but is not limited to, diluents, humectants, preservatives, antioxidants, etc., wherein examples of diluents include, but are not limited to, deionized water, physiological saline, phosphate buffer, etc.; examples of humectants include, but are not limited to, glycerin, propylene glycol, etc.; preservatives include, but are not limited to, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, phenoxyethanol, benzyl alcohol, etc.; and antioxidants include, but are not limited to, ascorbic acid, α-tocopherol, glutathione, gallic acid, etc. In a preferred embodiment, the pharmaceutically acceptable carrier is deionized water.

[0045] In this invention, skin wound regeneration and repair are achieved by administering a therapeutically effective amount of the composition to a subject. Subjects include, but are not limited to, mammals, including but not limited to, humans, mice, rabbits, cats, dogs, cattle, sheep, and pigs.

[0046] In this invention, the preferred method of administration of the composition is topical delivery. Accordingly, the compositions of this invention can be formulated into various clinically acceptable dosage forms, such as, but not limited to, gels, solutions, tinctures, glycerin preparations, ointments, patches, liniments, sprays, etc.

[0047] Preparation method One aspect of the present invention provides a method for preparing the photocatalytic material described herein, comprising the following steps: (1) A graphitic carbon nitride matrix is ​​dispersed in an aqueous solvent to obtain a suspension; (2) The suspension is mixed with a transition metal salt solution and an organic solvent to carry out a coordination reaction, thereby obtaining a single-atom transition metal-modified photocatalytic material. The single-atom transition metal forms an AN with the graphite-phase carbon nitride matrix. x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

[0048] The preparation method is described in detail below. In step (1) of the present invention, the source of graphitic carbon nitride is not particularly limited. It can be purchased from commercial products or prepared by known methods, such as by thermal polymerization. Preferably, the graphitic carbon nitride is surface-treated before dispersion. An exemplary surface treatment method includes immersing the graphitic carbon nitride in a 0.05-0.5 M (preferably 0.05-0.4 M, more preferably 0.05-0.3 M, for example 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3 M) hydrochloric acid aqueous solution and stirring at room temperature for 10-50 h, preferably 12-48 h, more preferably 14-46 h, further preferably 14-44 h, more preferably 14-42 h, and even more preferably 14-40 h. h, for example, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 h. It is understood that other acids that can protonate some N sites in the graphitic carbon nitride framework, thereby enhancing the subsequent metal coordination ability, are also within the scope of protection of this invention. For example, the above-mentioned hydrochloric acid can be replaced by nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, etc. Furthermore, those skilled in the art can clean or dry the graphitic carbon nitride or its surface treatment products as needed.

[0049] In step (1) of the present invention, the aqueous solvent is not particularly limited, and examples include but are not limited to deionized water, ultrapure water, distilled water, reverse osmosis water, etc.

[0050] In step (2) of this invention, the organic solvent is not particularly limited, and examples include, but are not limited to, ethanol, methanol, isopropanol, n-propanol, tert-butanol, ethylene glycol, glycerol, acetone, etc. The coordination reaction is carried out at 40-80°C, preferably 42-78°C, even more preferably 44-76°C, further preferably 46-74°C, more preferably 48-72°C, even more preferably 50-70°C, for example, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70°C for 1-10 h, preferably 1-9 h, even more preferably 1-8 h, further preferably 1-7 h, even more preferably 1-6 h, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 h. The transition metal salt is not particularly limited, and examples include, but are not limited to, nitrates, acetates, sulfates, acetylacetone salts, etc. Examples of transition metals include, but are not limited to, manganese, iron, cobalt, nickel, etc. The mass ratio of the graphitic carbon nitride to the metal salt is not particularly limited, as long as the Mn content in the final product is within a suitable range, such as 1-5 wt%.

[0051] application One aspect of the present invention provides the application of the photocatalytic material described herein in the preparation of products for skin wound regeneration and repair. The form of the product is not specifically limited; those skilled in the art will understand that the product can be in the form of a drug containing the photocatalytic material, or it can be in the form of a medical device containing the photocatalytic material.

[0052] The photocatalytic material of this invention stably anchors transition metals in single-atom form within a graphitic carbon nitride framework, thereby constructing an AN x The coordination center enables precise control of the local electronic structure and the overall band structure of the material, which not only significantly enhances the visible light absorption capacity and reduces the band gap energy, but also greatly improves the photogenerated electron-hole separation efficiency by changing the electron density distribution at the reaction interface, thereby improving the photocatalytic selective oxidation activity and thus enhancing the regenerative repair performance of skin wounds.

[0053] method One aspect of the present invention provides a method for selectively photocatalytically oxidizing or inactivating high-mobility group box 1 (HMP) proteins in cells, comprising the step of contacting and culturing cells in vitro with the photocatalytic material described in the present invention. In some embodiments, the method is for non-therapeutic purposes; for example, the method of the present invention can be used for drug screening, drug structure optimization, etc.

[0054] In this invention, selective photocatalytic oxidation or inactivation refers to inhibiting the migration activation state of high-mobility group box 1 (HMP-B1), particularly inhibiting its efflux from the cytoplasm, meaning that HMP-B1 is essentially or entirely retained within the cell nucleus. It is understood that inactivation means that, compared to the migration activity of HMP-B1 in cells treated with the photocatalytic material of this invention, the migration activity of HMP-B1 is reduced by at least 50%, preferably at least 80%, and even more preferably at least 90%, for example, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or even 100%.

[0055] Example 1 The following shows the preparation method and characterization of single-atom transition metal modified graphitic carbon nitride.

[0056] 1. Preparation method 1.1 Equipment and Reagent Instructions Material preparation equipment: muffle furnace (maximum temperature ≥1,000℃), magnetic stirrer and constant temperature heating device, ultrasonic cleaner, vacuum drying oven (temperature controllable 25-200℃), electronic balance (accuracy 0.1 mg).

[0057] Physicochemical characterization: Transmission electron microscopy (TEM), aberration-corrected scanning transmission electron microscopy (AC-HAADF-STEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and photoelectrochemical workstation (with a three-electrode system).

[0058] Computational simulation equipment: Density functional theory (DFT) calculation software platform (VASP, CASTEP, Gaussian).

[0059] 1.2 Preparation of CN Place 10 g of urea in an alumina crucible and incubate at 2 °C·min under air atmosphere. -1 The temperature was increased to 550℃ and held for 4 h. After cooling to room temperature, the resulting pale yellow solid was collected and washed with deionized water to remove unreacted urea and soluble impurities. The sample was then dried overnight at 60℃ to obtain primary g-C3N4 powder. To improve the surface chemical environment of the material, the powder was immersed in a 0.1 M hydrochloric acid aqueous solution and stirred at room temperature for 24 h to protonate some N sites in the framework, thereby enhancing the subsequent metal coordination ability. After treatment, the sample was filtered and repeatedly washed with deionized water until the washing solution was neutral. Finally, it was vacuum dried overnight at 60℃, and the resulting powder was collected and designated CN.

[0060] 1.3 Preparation of single-atom Mn-modified graphitic carbon nitride 100 mg of CN was weighed and dispersed in 20 mL of deionized water, and stirred to form a stable suspension. Then, MnCl2 solution and 5 mL of anhydrous ethanol were added sequentially (Mn-CN was prepared at 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt% by controlling the amount of MnCl2 solution used). The mixture was stirred continuously at 60 °C for 4 h to allow the Mn-CN to settle. 2+ The material undergoes complete coordination fixation with the N sites on the CN surface. After the reaction is complete, the product is collected by centrifugation and washed multiple times with ethanol and deionized water to remove free metal ions and impurities. Finally, it is vacuum dried overnight at 60°C to obtain a uniform single-atom Mn-modified graphitic carbon nitride (Mn-CN) powder.

[0061] 2. Characterization 2.1 Material structure characterization and electronic structure analysis To determine the structural characteristics of the Mn-CN material in this embodiment and the actual anchoring state of single-atom manganese in the matrix, a systematic physicochemical structural analysis was performed on the Mn-CN powder. The results of transmission electron microscopy (TEM) are as follows: Figure 1 As shown in Figure A, the characterization results of the high-resolution spherical aberration corrected scan image (AC-HAADF) are as follows: Figure 1As shown in B, no metal clusters or nanoparticles were observed in the sample. Manganese was highly dispersed in the CN surface and pore region in the form of single atoms, indicating that a single-atom catalytic structure was successfully constructed.

[0062] X-ray diffraction (XRD) patterns are as follows: Figure 2 As shown in Figure A, Mn-CN retains the typical crystallographic characteristic peaks of CN, indicating that the introduction of manganese did not disrupt the original heptazine framework structure, and the overall crystal integrity of the material is good. The Fourier transform infrared (FTIR) spectroscopy analysis results are as follows... Figure 2 As shown in Figure B, the introduction of Mn alters the local electronic environment of the framework. The shifts in the 2p peak of Mn and the 1s shift of N indicate the formation of a stable Mn-N matrix within the material. x The coordination structure verifies the successful anchoring of metal atoms at the electronic structure level.

[0063] X-ray photoelectron spectroscopy (XPS) analysis results are as follows: Figure 3 As shown, due to the extremely low Mn loading, its signal was not clearly detected, but the C, N, and O element spectral peaks of the carrier CN did not shift significantly, indicating that the loading of single-atom Mn did not significantly change the chemical environment of the carbon nitride surface.

[0064] In summary, the Mn-CN material of this invention exhibits significant advantages in terms of structural integrity, metal atom dispersion, and electronic structure regulation.

[0065] 2.2 Photoelectric property analysis To determine the photogenerated carrier behavior of the Mn-CN material in this embodiment, its photoelectric properties were systematically tested. The transient photocurrent (TPC) measurement results are as follows: Figure 4 As shown, the photocurrent density generated by Mn-CN under visible light irradiation is significantly higher than that of CN, with its photocurrent intensity generally being 3-5 times that of CN. This indicates that the introduction of Mn single atoms can effectively promote the rapid separation and migration of photogenerated electrons and holes. Simultaneously, the photocurrent response of Mn-CN increases more rapidly, and the signal remains stable without significant attenuation during the photo-switching cycle, demonstrating its excellent carrier migration stability. Combining the charge separation efficiency and related impedance spectroscopy results, it can be concluded that Mn-N... x The coordination structure creates efficient electron transport channels within the material, making Mn single atoms active centers that promote directional charge migration, thereby significantly reducing the electron-hole recombination rate. In summary, the material of this embodiment exhibits significant advantages in photoelectronic behavior, providing a reliable basis for its excellent catalytic activity in visible light-driven selective oxidation reactions.

[0066] 2.3 Photocatalytic Reaction Performance Analysis To evaluate the catalytic activity of the Mn-CN material in this embodiment under visible light conditions, the selective oxidation reaction of toluene was used as a model system for photocatalytic performance testing. Specifically, 10-20 mg of different samples (including 3 wt% Mn-CN and control CN from this embodiment) were added to a mixed solvent system containing toluene, and the catalytic reaction was carried out under visible light irradiation with a wavelength greater than 420 nm in an air or oxygen atmosphere. The experimental results are as follows: Figure 5 As shown, the Mn-CN material in this embodiment exhibits significantly enhanced oxidation activity under visible light irradiation. The 3 wt% Mn-CN material demonstrates the best performance, producing approximately 500-800 μmol of benzaldehyde, significantly higher than the yield of unmodified CN, which is only about 20% of that of Mn-CN, indicating that the activity of intrinsic CN is limited. Furthermore, under catalyst-free, dark, or inert atmosphere conditions, almost no oxidation products were detected in the reaction system, demonstrating that light, oxygen, and an active catalyst are all indispensable. In summary, the introduction of single-atom Mn significantly enhances the photogenerated carrier separation capability and substrate activation efficiency of the material, enabling Mn-CN to exhibit far superior catalytic performance to the control material in visible light-driven selective oxidation reactions.

[0067] 2.4 Density Functional Theory Analysis To further elucidate the source of the high activity of Mn-CN materials in visible-light selective oxidation reactions, density functional theory (DFT) calculations were performed on the electronic structure and reaction energy barrier of CN and Mn-CN. The calculation results are as follows: Figure 6 As shown, the introduction of Mn atoms can form a stable Mn-N matrix in CN. x The coordination structure, with its surrounding electron distribution significantly rearranged, results in a greater number of electronic states in the total density of states (DOS) near the Fermi level that can participate in photogenerated transitions, which is beneficial for enhancing visible light absorption and the excitation efficiency of photogenerated carriers. Simultaneously, the introduction of Mn significantly alters the reaction energy pathway at the catalytic interface. In the selective oxidation of toluene, the rate-limiting free energy barrier of CN is approximately +0.30 eV, while that of Mn-CN decreases to approximately -0.04 eV, indicating that the reaction process shifts from barrier-bound to thermodynamically spontaneous, which is beneficial for substrate activation and oxidation product formation. Further adsorption energy and charge density difference analysis results are as follows... Figure 7 As shown, Mn-N x The coordination center can stably bind aromatic substrates and effectively reduce the CH bond breaking energy through d-orbital-π electronic coupling, thereby significantly promoting the formation of reaction intermediates and electron transfer. The above calculation results are consistent with experimental characterization conclusions, fully demonstrating that the Mn single-atom center constructed in this embodiment is a key factor in achieving efficient photocatalytic selective oxidation.

[0068] Example 2 The following illustrates the selective oxidation effect and skin wound regeneration and repair effect of the single-atom transition metal modified graphitic carbon nitride prepared in Example 1.

[0069] 1. Selective oxidation 1.1 Toluene To verify the photocatalytic selective oxidation performance of Mn-CN materials, a visible light-driven oxidation reaction was conducted using toluene as a model substrate. Specifically, 50 mg of 3 wt% Mn-CN material was added to a mixed solvent containing 5 mL of toluene and 20 mL of acetonitrile / water (volume ratio 4:1), placed in a 50 mL sealed quartz flask, and air was introduced as the oxidant. The reaction was run at room temperature (25±2℃) with magnetic stirring (700 rpm), and the flask was exposed to a visible light LED light source (300 W) with a wavelength greater than 420 nm for 6–12 h. Control experiments included conditions without catalyst, without light, inert gas (Ar) atmosphere, and using unmodified CN material to confirm the contribution of Mn single atoms.

[0070] The results show that Mn-CN can effectively activate and selectively oxidize toluene under visible light irradiation, with benzaldehyde and a small amount of benzoic acid as the main products. The selectivity of benzaldehyde exceeds 85%, and the proportion of benzoic acid is about 10-15%. Under the same conditions, the total product yield of 3wt% Mn-CN can reach 600-800 μmol, which is significantly higher than the 120-200 μmol of unmodified CN material, and its photocatalytic activity is 4-6 times that of CN. However, almost no product formation was observed under the conditions of no light, no catalyst, or inert atmosphere, indicating that the reaction depends on the synergistic effect of photogenerated charge carriers and single-atom Mn active centers. This fully demonstrates the excellent activity and high selectivity of the material prepared in Example 1 in visible light-driven selective oxidation reaction.

[0071] Unmodified CN exhibits low photogenerated carrier separation efficiency under illumination, weak transient photocurrent response, longer time to reach stable photocurrent, and an overall photocurrent density less than 20% of that of Mn-CN, indicating a significantly higher photogenerated electron-hole recombination rate than Mn-CN. Further comparison of the reaction performance of the two materials under different conditions reveals that CN shows almost no catalytic activity in the absence of light, oxygen, or an inert atmosphere, while Mn-CN exhibits significant reaction rate and selectivity under illumination, fully demonstrating the significant regulatory effect of the Mn single-atom coordination structure on photogenerated carriers. Density functional theory (DFT) calculations also support these results: CN has a higher reaction free energy barrier during toluene adsorption and CH activation, while the rate-limiting step barrier of Mn-CN decreases to approximately -0.04 eV, which is more conducive to substrate electron transfer and reaction pathway advancement. In summary, unmodified CN is significantly weaker than Mn-CN in terms of light absorption capacity, electron separation efficiency, reaction activity, and selectivity. This invention constructs a stable Mn-N... x The single-atom active center successfully achieved a significant enhancement of photoelectric behavior and a systematic reduction of the reaction energy barrier, forming a highly efficient photocatalytic selective oxidation system that is far superior to CN.

[0072] 1.2 HMGB1 To further elucidate the mechanism of action of Mn-CN material in regulating HMGB1 in cells, DAPI / HMGB1 dual immunofluorescence staining was performed on blank control cells, cells treated with 4 wt% Mn-CN, and cells treated with 3 wt% Mn-CN.

[0073] The results are as follows Figure 8 As shown, in the control group, HMGB1 was significantly distributed in the perinuclear and cytoplasmic regions, exhibiting a clear outflow trend, indicating that the cells were in an inflammation-related HMGB1 migration activation state. This trend was significantly inhibited after treatment with Mn-CN material. In the 4 wt% Mn-CN group, the overall HMGB1 fluorescence signal was weakened, and it tended to remain more within the nucleus. The inhibitory effect was even more pronounced in the 3 wt% Mn-CN group, with HMGB1 outflow in the cytoplasm almost completely suppressed, while the red fluorescence within the nucleus remained concentrated, demonstrating its significant regulatory role in HMGB1 subcellular localization.

[0074] Further comparison of the effects of different concentrations of Mn-CN was conducted using the Mn-N constructed in Example 1. x The single-atom active center and its photocatalytic oxidation ability can effectively block the inflammation-related translocation process of HMGB1 and weaken the cellular stress response triggered by DAMPs. The above immunofluorescence results are consistent with the photocatalytic activity of the material and the mechanism of DFT barrier reduction, which fully demonstrate that Mn-CN has the ability to significantly stabilize HMGB1 localization and inhibit its abnormal efflux in the cellular inflammatory microenvironment.

[0075] 2. Skin wound regeneration and repair To further verify the promoting effect of Mn-CN material on wound repair in vivo, a comparative observation was conducted on the blank control group, the treatment with 4wt% Mn-CN and 3wt% Mn-CN. When using Mn-CN, it was prepared into a suspension by adding deionized water and applied dropwise to the wound. The healing process of full-thickness skin defects in mice was observed within 0-7 days.

[0076] The results are as follows Figure 9 As shown, in the control group, the wound area remained significantly exposed during Days 1-3, with slow necrotic scab formation. Significant exudation and tissue collapse were still visible on Day 5, and limited wound area shrinkage was observed by Day 7, indicating a relatively slow natural healing process. In contrast, the 4 wt% Mn-CN group showed more uniform early granulation tissue coverage on Day 1, significantly accelerated tissue shrinkage on Day 3, and a stable dry scab formed by Day 5, with regular healing edges and more abundant new tissue growth. Notably, the 3 wt% Mn-CN group exhibited the most significant promoting effect: the wound showed more complete early closure signs on Day 1, significantly accelerated tissue re-epithelialization on Day 3 rapidly reduced the wound area, and near-complete closure was achieved by Day 5. By Day 7, only a very small scab area remained, with an overall healing speed significantly superior to the 4 wt% Mn-CN and control groups.

[0077] In summary, the Mn-N constructed by this invention x In vivo, the single-atom active center can selectively oxidize DAMPs (such as HMGB1) through efficient photocatalysis, thereby inhibiting early excessive inflammatory responses, preventing excessive tissue damage, and promoting subsequent granulation tissue formation and re-epithelialization. The optimal dose-effect of 3 wt% Mn-CN is consistent with its strongest HMGB1 regulation ability, lowest reaction energy barrier, and highest photoelectric performance exhibited in vitro. Furthermore, the wound healing results are highly consistent with the aforementioned molecular mechanism studies, clearly demonstrating that Mn-CN materials can effectively remodel the damaged microenvironment, significantly accelerate skin wound repair, and can be used for tissue regeneration.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composition for skin wound regeneration and repair, characterized in that, The composition includes a photocatalytic material comprising a graphitic carbon nitride matrix and a single-atom transition metal, wherein the single-atom transition metal and the graphitic carbon nitride matrix form an AN... x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

2. The composition for skin wound regeneration and repair according to claim 1, characterized in that, The transition metal includes at least one of manganese, iron, cobalt, and nickel.

3. The composition for skin wound regeneration and repair according to claim 1, characterized in that, It further includes pharmaceutically acceptable carriers.

4. The composition for skin wound regeneration and repair according to claim 3, characterized in that, The pharmaceutically acceptable carrier includes at least one of diluents, humectants, preservatives, and antioxidants.

5. A method for preparing a photocatalytic material for skin wound regeneration and repair, characterized in that, It includes the following steps: (1) A graphitic carbon nitride matrix is ​​dispersed in an aqueous solvent to obtain a suspension; (2) The suspension is mixed with a transition metal salt solution and an organic solvent to carry out a coordination reaction to obtain a single-atom transition metal modified photocatalytic material, wherein the single-atom transition metal forms an AN with the graphite-phase carbon nitride matrix. x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

6. The preparation method according to claim 5, characterized in that, The process further includes surface treatment of the graphitic carbon nitride matrix prior to dispersion.

7. The preparation method according to claim 5, characterized in that, The transition metal salt includes at least one of nitrate, acetate, sulfate, and acetylacetone.

8. The preparation method according to claim 5, characterized in that, The conditions for the coordination reaction include: a reaction temperature of 40-80℃ and a reaction time of 1-10 h.

9. The application of photocatalytic materials in the preparation of repair products for skin wound regeneration, characterized in that, The photocatalytic material comprises a graphitic carbon nitride matrix and a single-atom transition metal, wherein the single-atom transition metal and the graphitic carbon nitride matrix form AN. x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

10. A method for selectively photocatalytically oxidizing or inactivating high-mobility group box protein B1 in cells, characterized in that, It includes the step of contacting cells with a photocatalytic material in vitro, the photocatalytic material comprising a graphitic carbon nitride matrix and a single-atom transition metal, wherein the single-atom transition metal and the graphitic carbon nitride matrix form an AN x Coordination structure, where A is a transition metal element and x is an integer greater than 1.

Images