CN115433475B

CN115433475B - Photoelectric response type manganese oxide-carbon composite coating, preparation method thereof and application thereof in nerve and bone tissue repair

Info

Publication number: CN115433475B
Application number: CN202110619658.0A
Authority: CN
Inventors: 李恺; 刘诗伟; 邵丹丹; 闫咨汝; 谢有桃; 郑学斌
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2023-04-07
Anticipated expiration: 2041-06-03
Also published as: CN115433475A

Abstract

The invention discloses a photoelectric response type manganese oxide-carbon composite coating, a preparation method thereof and application thereof in nerve and bone tissue repair. The manganese oxide-carbon coating is a biological coating which is formed by loading a carbon material on the surface of a manganese oxide nanosheet layer with a communicating pore structure in situ, wherein the carbon material is wrapped on the surface of the manganese oxide nanosheet layer and is tightly contacted with manganese oxide so as to rapidly transfer photoelectrons generated by the manganese oxide under the illumination condition; the mass ratio of carbon in the biological coating is 1-30%, preferably 5-25%. The composite coating has good biological activity and photoelectric response characteristics, can generate photocurrent under external illumination to stimulate nerve cells to proliferate, can promote nerve cells to release neuropeptide, and can potentially regulate and control bone tissue repair. Meanwhile, osteoblasts on the surface of the manganese oxide-carbon exhibit better osteogenic differentiation capacity under the irradiation of light.

Description

Photoelectric response type manganese oxide-carbon composite coating, preparation method thereof and application thereof in nerve and bone tissue repair

Technical Field

The invention relates to a photoelectric response type manganese oxide-carbon composite coating, a preparation method thereof and application thereof in nerve and bone tissue repair, belonging to the technical field of biomedicine.

Background

In the human skeletal system, nervous tissue is distributed mainly in areas of active bone metabolism, and its normal function is essential for maintaining the skeletal microenvironment stable and promoting fracture healing. For example, when a human body is fractured, calcitonin Gene Related Peptide (CGRP) secreted from nerve cells can promote bone tissue regeneration, which is beneficial to realizing osseointegration of the bone implant material after surgery. However, when the nervous system is diseased or functionally damaged, the peripheral nerve of the fracture is innervated insufficiently, which causes the fracture site to often show low strength of callus, delayed union of the fracture, and nonunion, severely limiting the bone repair process. Therefore, the development of a novel bone repair material having a function of promoting good nerve regeneration is of great significance in promoting bone repair of patients with nervous system disorders or injuries.

The metallic titanium and the alloy thereof have good biocompatibility, chemical stability and corrosion resistance, and are clinically common bone implant materials. The biological inertness of the titanium surface, however, makes it deficient in its ability to promote osteogenesis and nerve regeneration. The electrical signal is a biological signal commonly existing in tissues such as nerves and bones of a human body, and plays an important role in regulating cell proliferation, migration, gene expression and the like. In recent years, as an electrical stimulation mode with low cost, high safety, and good controllability, non-invasive photoelectric stimulation has been widely used to study the repair of nerves, bones, muscles, and the like. Therefore, the biological coating with photoelectric response characteristic is prepared on the surface of the titanium and the titanium alloy, and is expected to stimulate osteoblasts and nerve cells sensitive to electric signals, so as to achieve the aim of promoting the rapid repair of bone and nerve tissues.

The existing research shows that the TiO is stimulated by light ₂ The base coating may regulate cell adhesion, growth and differentiation. However, tiO ₂ The band gap of the semiconductor material is wide (3.1 eV), and the semiconductor material can only respond to ultraviolet light with short wavelength, and the high-energy ultraviolet light irradiation is easy to cause cell damage. In contrast, manganese oxide is a common narrow band gap (1.4-2.7 eV) semiconductor material, has a strong light absorption capability in the visible-part infrared light band, and can avoid cytotoxicity caused by using ultraviolet light. Further, an appropriate amount of Mn ²⁺ It also activates cell integrins, activates intracellular signaling pathways, and facilitates differentiation of neural or osteoblastic cells. However, manganese oxide semiconductors have insufficient conductivity and are not conducive to efficient separation of photogenerated electrons and holes.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a photoelectric response type manganese oxide-carbon composite coating, a preparation method thereof and application thereof in nerve and bone tissue repair. The composite coating has good biological activity and photoelectric response characteristics, can generate photocurrent under external illumination to stimulate nerve cells to proliferate, can promote nerve cells to release neuropeptide, and can potentially regulate and control bone tissue repair. Meanwhile, osteoblasts on the surface of the manganese oxide-carbon exhibit better osteogenic differentiation capacity under the irradiation of light.

In a first aspect, the present invention provides a photo-responsive manganese oxide-carbon composite coating. The manganese oxide-carbon coating is a biological coating which loads a carbon material on the surface of a manganese oxide nanosheet layer with a communicating pore structure in situ. The introduction of the carbon material layer reserves the structure of the manganese oxide nanosheet layer and the communicating pore, has the characteristic of large specific surface area, can promote the adhesion of cells and can enhance the stimulation effect of photoelectric signals on the cells. The carbon material in the composite coating wraps the surface of the manganese oxide sheet and is in close contact with the manganese oxide so as to rapidly transfer photoelectrons generated by the manganese oxide under the illumination condition. In some technical schemes, the composite coating combines manganese oxide with a carbon material (such as graphite or carbon nanotubes) with good conductivity, promotes the rapid transfer of photogenerated carriers in manganese oxide, improves the light absorption range of the material, promotes the regeneration of nerve and bone tissues through photoelectric stimulation, and provides possibility for researching and developing novel photoelectric response type coating materials for bone-nerve tissue repair.

The mass ratio of carbon in the biological coating is 1-30%. At the moment, the carbon material can obviously enhance the conductivity of the composite coating, improve the photoelectric response characteristic and keep the nano structure of the manganese oxide layer. The mass ratio of carbon may be more preferably 5 to 25%.

Preferably, the manganese oxide nano-sheet is formed by manganese oxide particles with the particle size of 0.01-2 μm, and the thickness of the nano-sheet is 1-30nm.

Preferably, the pore diameter of the communication pore structure is 0.02-2 μm.

Preferably, the thickness of the composite coating is 1-20 μm, preferably 1-5 μm.

In a second aspect, the invention provides a preparation method of the photoelectric response type manganese oxide-carbon composite coating. The preparation method comprises the following steps:

(1) Preparing a manganese oxide coating by hydrothermal reaction: potassium permanganate is used as a manganese source, hydrochloric acid is used as a reducing agent, potassium chloride is used as a structure stabilizer, the raw materials are dissolved in deionized water to obtain a mixed solution, and then the mixed solution is used for in-situ growth of a manganese oxide sheet layer on the surface of a base material by adopting a hydrothermal reaction method;

(2) And (2) soaking the manganese oxide sheet layer prepared in the step (1) in a glucose solution for a period of time, and annealing at 200-600 ℃ for 1-4h in an argon atmosphere to obtain the photoelectric response type manganese oxide-carbon composite coating.

The invention adopts a hydrothermal reaction combined high-temperature carbonization method to grow a manganese oxide-carbon (MnO-C) composite coating with a nano structure on the surface of a base material in situ.

Preferably, the base material comprises a medical metal or alloy material, preferably at least one of pure titanium, a titanium alloy, stainless steel or a cobalt-chromium-molybdenum alloy.

Preferably, in the step (1), the concentration of the potassium permanganate is 0.001-0.01mol/L, the concentration of the hydrochloric acid is 1-5 times of the potassium permanganate, and the concentration of the potassium chloride is 1-5 times of the potassium permanganate.

Preferably, in the step (1), the hydrothermal reaction temperature is 80-180 ℃ and the hydrothermal reaction time is 0.5-24h. By controlling the hydrothermal reaction temperature and the reaction time within the above ranges, a nanosheet structure can be formed on the surface of the substrate and prevented from being damaged.

Preferably, in the step (2), the concentration of the glucose solution is 0.1-2wt.%, and the soaking time is 2-48h.

Preferably, in the step (2), the annealing temperature is 200-600 ℃ and the time is 1-4h. The annealing temperature is too low, and the annealing time is too short, which is not favorable for converting glucose adsorbed on the surface of the manganese oxide into a carbon material with good conductivity, such as graphite. The annealing temperature is too high, the annealing time is too long, and the nano sheet structure is easy to damage.

In a third aspect, the invention provides an application of the photoelectric response type manganese oxide-carbon composite coating in nerve and bone tissue repair.

Drawings

FIG. 1 is an SEM of MnO and MnO-C coatings;

in FIG. 2, A is the XRD pattern of the MnO and MnO-C coating and B is the Raman pattern of the MnO and MnO-C coating;

in FIG. 3, A is the Electrochemical Impedance Spectroscopy (EIS) of MnO and MnO-C coatings and B is the UV-Vis-NIR diffuse reflectance spectra of MnO and MnO-C coatings;

in FIG. 4, A is a photocurrent density curve of different samples under red light irradiation, and B is a photocurrent density curve of the MnO-C composite coating when VC is added;

in FIG. 5, A is the proliferation of PC12 cells on the surface of different samples, and B is the amount of released CGRP;

in FIG. 6, A is ALP activity of MC3T3-E1 cells on the surface of different samples, and B is calcium deposition amount.

Detailed Description

The present invention is further illustrated by the following examples, which are to be construed as merely illustrative, and not a limitation of the present invention. Unless otherwise specified, each percentage refers to a mass percentage.

The disclosure provides a photoelectric response type manganese oxide-carbon composite coating for promoting nerve and bone tissue repair, and a preparation method and application thereof. The manganese oxide-carbon composite coating (also called as MnO-C composite coating) is a biological coating which is formed by loading a carbon material layer on the surface of a manganese oxide nanosheet layer with a communicated pore structure in situ. Photoelectrons are generated in the manganese oxide semiconductor material under the illumination condition and are transferred to the cell surface through the carbon material. Therefore, the composite coating of the invention designs the carbon material on the surface of the manganese oxide sheet layer, which is convenient for the carbon material to contact with cells or tissues, thereby ensuring that the electric signal is transferred from the manganese oxide to the cells or tissues. It is noted that the manner of depositing manganese oxide on the surface of carbon materials is not suitable for the present invention because the properties of manganese oxide semiconductors that are not sufficiently conductive to facilitate efficient separation of photogenerated electrons and holes do not allow for smooth transfer of light conditions to cells or tissues. Therefore, the carbon material in the composite coating of the invention is wrapped on the surface of the manganese oxide lamellar structure and is tightly contacted with the manganese oxide, so that photoelectrons generated in the manganese oxide can be rapidly transferred to tissues or cells.

The load of the carbon material in the composite coating of the invention enables the biological coating to still maintain the structure of the nano-sheet layer and the structure of the interconnected pores (as shown in figure 1). The nanosheet structure can promote the adhesion of nerve and osteoblast, and the coating has a larger specific surface area; the intercommunicating pore structure can expose more active sites, is beneficial to the transfer of photo-generated electric signals at a material-solution interface, and enhances the stimulation effect of the electric signals on cells. The manganese oxide-carbon composite coating utilizes the synergy between the semiconductor property of manganese oxide and the conductivity of a conductive material, particularly the semiconductor property of manganese oxide, so that the manganese oxide-carbon composite coating generates photo-generated electrons under the illumination of certain wavelength, and the carbon material with good conductivity transfers the photo-generated electrons to tissues or cells, thereby stimulating the regeneration of bone tissues sensitive to electric signals.

Compared with a MnO coating, the MnO-C composite coating has better photoelectric response characteristic and bioactivity, can stimulate nerve cell proliferation and osteoblast differentiation under external illumination, is a potential biomedical material, and can be used for research and development of bone repair materials for patients with nervous system pathological changes or injuries.

The preparation method of the MnO-C composite coating is characterized in that a manganese oxide nanosheet layer grows on the surface of a base material in an in-situ hydrothermal mode, and a carbon material is loaded on the surface of the nanosheet layer through a high-temperature carbonization method to obtain the MnO-C composite coating with a nanosheet structure and a communicating pore structure. The following is an exemplary description of a method for preparing the MnO-C composite coating having the function of promoting regeneration of nerve and bone tissues.

Hydrothermal reaction: potassium permanganate is used as a manganese source, hydrochloric acid is used as a reducing agent, and potassium chloride is used as a structure stabilizer. Dissolving the raw materials in deionized water to obtain a mixed solution. The raw materials can be added into deionized water together, or the raw materials can be added sequentially or in several times. In the mixed solution, the concentration of the potassium permanganate is 0.001-0.01mol/L, the concentration of the hydrochloric acid is 1-5 times of that of the potassium permanganate, and the concentration of the potassium chloride is 1-5 times of that of the potassium permanganate. And (3) placing the base material in the mixed solution, and growing a manganese oxide coating on the surface of the base material in situ by adopting a hydrothermal reaction method to obtain the base material with the surface coated by the nano-sheets. The substrate includes, but is not limited to, pure titanium, titanium alloy, stainless steel, or cobalt chromium molybdenum alloy, among others. The reaction temperature of the hydrothermal reaction method is 80-180 ℃, and preferably 100-150 ℃. The hydrothermal reaction is carried out for 0.5-24h, preferably 8-15h. Preferably a titanium substrate, in which case the surface of the titanium substrate is capable of adsorbing metallic manganese ions and reacting on the surface of the substrate to form manganese oxide grains. Along with the prolonging of the reaction time, the manganese oxide crystal grains gradually grow into nano sheets, and are interwoven on the surface of the base material to form a communication hole structure.

High temperature carbonization. And soaking the manganese oxide coating prepared by the hydrothermal reaction in a glucose solution for a period of time, and annealing in argon to obtain the MnO-C composite coating. The concentration of the glucose solution is 0.1-2wt.%, preferably 0.3-1wt.%. The soaking time is 2-48h, preferably 8-24h. The annealing temperature is 200-600 ℃, preferably 300-500 ℃. The annealing time is 1-4h, preferably 1.5-3h. The manganese oxide nanosheet layer with the interconnected pore structure is convenient for absorbing glucose solution, and the glucose solution can be used as a carbon precursor and can be carbonized at high temperature to form a carbon material with high conductivity. The method has the advantages of simple and easily obtained raw materials, uniform product structure and capability of still maintaining the structure of the communicating holes after carbonization.

The obtained composite coating has good biological activity and photoelectric response characteristic, can stimulate nerve cell proliferation under external illumination, is beneficial to nerve tissue repair and release of neuropeptide, and is suitable for regulating and controlling bone tissue repair potentially. In addition, osteoblasts on the surface of MnO-C show better osteogenic differentiation capacity under the irradiation of light.

The present invention will be described in further detail with reference to examples. The present invention is further illustrated by the following specific examples, which are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. The invention is not limited to the specific embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed. The specific process parameters and the like in the following examples are also only one example of suitable ranges, and the person skilled in the art can make a selection within suitable ranges through the description herein, and are not limited to the specific values exemplified below.

Example 1

Preparation of MnO-C composite coating

And (3) placing the titanium sheet polished by the abrasive paper into a mixed solution of potassium permanganate, potassium chloride and hydrochloric acid, and growing a manganese oxide coating on the surface of the titanium sheet in situ by adopting a hydrothermal reaction method. Soaking the manganese oxide coating prepared by the hydrothermal reaction in a glucose solution for a period of time, and preparing the MnO-C composite coating by adopting a high-temperature carbonization method (annealing in an argon atmosphere). The volume of the ionic mixed liquid used in the hydrothermal reaction method is 60mL, the concentration of potassium permanganate is 0.001mol/L, the concentration of potassium chloride is 0.003mol/L, and the concentration of hydrochloric acid is 0.004mol/L. The hydrothermal reaction time is 12h, and the hydrothermal reaction temperature is 120 ℃. The concentration of the glucose solution used in the high-temperature carbonization method is 0.5wt.%, and the soaking time is 24h. The annealing temperature is 450 ℃, and the annealing time is 2h.

And (3) directly annealing the coating obtained by the hydrothermal reaction at 450 ℃ in an argon atmosphere for 2h to obtain an MnO coating as a reference.

And after the preparation of the coating is finished, analyzing the surface appearance of the MnO and MnO-C coating. As can be seen from the SEM photograph shown in fig. 1, both coatings are of a nanosheet structure.

From the XRD pattern shown as A in FIG. 2, it can be seen that the main phase of both the MnO and MnO-C coating samples is MnO (JCPDS card No: 89-4835).

As can be seen from the raman spectrum shown as B in fig. 2, the MnO coating contains only the oscillation peak of manganese oxide, and the MnO-C coating contains oscillation peaks of manganese oxide and C. The vibration peak of C is obvious G peak (1602 cm) ^-1 Sp2 hybridized C atom in the graphite lattice) and D peak (1357 cm ^-1 Graphite defects, corresponding to amorphous carbon). The intensity ratio of the G peak to the D peak is about 1.72, which shows that the carbon material prepared by the high-temperature carbonization method has higher graphitization degree, and the conductivity of the coating can be obviously enhanced.

As can be seen from the EDS test results shown in table 1, the C content in the MnO-C composite coating was 11.78at.%.

TABLE 1 EDS elemental analysis of MnO-C composite coatings

Sample (I)	Mn(at.％)	O(at.％)	C(at.％)	Ti(at.％)
					MnO-C	12.45	43.72	11.78	32.05

Photoelectrochemical activity detection of MnO-C composite coating

Adopting a three-electrode system (a saturated calomel electrode is a reference electrode, a platinum sheet is a counter electrode, a titanium sheet covered with a coating is a working electrode) and adding 0.5mol/L of Na ₂ SO ₄ In solution, the EIS curves of the samples were tested using an electrochemical workstation (Corrtest, china). The EIS has a frequency range of 100,000-0.1Hz. The samples were tested for their UV-Vis-NIR diffuse reflectance spectra by means of an ultraviolet-visible spectrophotometer (Metash, china).

Testing the photocurrent response curve of the sample through an electrochemical workstation, wherein the testing solution is 0.5mol/L of Na ₂ SO ₄ The light source is a 650nm (0.1W power) laser. The photocurrent curve of the samples was tested in potentiostatic (1V versus SCE) mode with/without light. Wherein the time of light and dark is set toFor 30s. Photovoltage and photocurrent response curves of part of the samples were measured on Na containing ascorbic acid (Vitamin C, VC) at a concentration of 1mM ₂ SO ₄ In solution.

As can be seen from a in fig. 3, the smaller circular arc diameter of the EIS spectrum of the MnO — C composite coating in the high frequency region compared to MnO means that the introduction of carbon material reduces the electrochemical impedance of the nanocomposite coating, which facilitates the transfer of photogenerated charges in the material to the solution.

From the UV-Vis-NIR diffuse reflectance spectra of the samples as shown in B in FIG. 3, the MnO-C composite coating has a stronger light absorption capability. Direct band gaps of MnO and MnO-C are respectively 1.85eV and 1.65eV calculated by UV-Vis-NIR diffuse reflection spectroscopy, and the direct band gaps can be respectively excited by monochromatic light with the wavelength of less than 670nm and 751 nm.

The photocurrent response curves of the samples as shown in a in fig. 4 show that the photocurrent densities generated by different samples when irradiated with red light exhibit the following trends: 1 muA/cm ² (MnO-C)＞0.4μA/cm ² (MnO)＞0.1μA/cm ² (Ti). When the hole scavenger VC (vitamin C) is added, the photocurrent density of the MnO-C composite coating is rapidly increased to 2.5 muA/cm ² As shown at B in fig. 4. Therefore, the support of the carbon material can enhance the photoelectric activity of the MnO-C composite coating, and the hole scavenger can enhance the photoelectric response capability of the composite coating by inhibiting the recombination of photogenerated electrons and holes in the composite coating.

Proliferation behavior of nerve cells on surface of MnO-C composite coating and neuropeptide secretion detection

Rat adrenal pheochromocytoma PC12 cells were used for nerve cell-related experiments.

(1) Cell proliferation

The density is 2 x 10 ⁴ PC12 cells per well were seeded on the surface of the sterilized sample, VC was added to a final concentration of 5mM to a portion of the wells, and the sample was irradiated for 20-30min using an LED lamp (peak wavelength 650nm, scintillation mode) with a power of 3W. After 24h of culture, cell proliferation was detected by the CCK-8 method.

(2) Amount of secreted CGRP neuropeptide

The density is 5 multiplied by 10 ⁴ PC12 cells in wellA final concentration of 5mM VC was added to a portion of the wells. After incubation for 24h, part of samples are irradiated for 20-30min by using an LED lamp (the peak wavelength is 650nm, the scintillation mode) with the power of 3W, and the content of CGRP in the culture solution is detected by adopting an ELISA method.

A in figure 5 is the proliferation result of PC12 cells cultured on the surface of different samples for 24h, and the MnO-C composite coating can obviously promote the proliferation of PC12 cells on the surface under normal culture conditions. Under the irradiation of red light, compared with a Ti substrate and an MnO coating, the MnO-C composite coating can obviously promote the proliferation of PC12 cells, wherein the cell proliferation rate of an MnO-C (VC) group is the highest. Red light irradiation increased cell activity in the MnO-C and MnO-C (VC) groups compared to normal culture conditions. Therefore, the load of the carbon material is beneficial to improving the photoelectric activity and biocompatibility of the MnO-C composite coating, and the composite coating can promote the proliferation of nerve cells on the surface of the composite coating through photoelectric signals.

B in fig. 5 is the CGRP secretion of PC12 cells on the surface of different samples, and it was found that the surface of MnO-C composite coating promoted the secretion of CGRP by PC12 cells compared to MnO coating and Ti substrate. The illumination energy can obviously promote the nerve cells of the MnO-C (VC) group to secrete CGRP, and the secretion amounts are respectively 1.23 times and 1.49 times of those of the Ti and MnO experimental groups, which indicates that the photocurrent promotes the PC12 cells to release neuropeptide. Because the neuropeptide can promote mitosis of osteoblasts and up-regulate expression of genes related to osteoblast differentiation, so that bone formation is promoted, PC12 cells with high CGRP secretion on the surface of the material have the potential of promoting osteoblast differentiation.

Differentiation behavior of osteoblasts on MnO-C composite coating surface

Osteoblast differentiation experiments were performed using mouse preosteoblasts MC3T 3-E1.

(1) Alkaline phosphatase (ALP) Activity

MC3T3-E1 cells were seeded on the surface of the sterilized sample, VC was added to a final concentration of 5mM to a portion of the wells, and a portion of the sample was irradiated (peak wavelength 650nm, scintillation mode) for 20-30min/d using an LED lamp with a power of 3W. After 14 days of incubation, 200. Mu.L of 0.2% Triton X-100 in PBS was added to each well and lysed on ice for 15min. The lysed suspension was then centrifuged for 5min and the supernatant collected and transferred to a 96-well plate. mu.L of the supernatant was mixed with 150. Mu.L of p-nitrophenylphosphate (pNPP) and incubated for 10min in the absence of light. And measuring the OD value of the supernatant by using a microplate reader. In addition, the total protein content in the cells was measured by BCA method, and ALP activity was expressed in. Mu.M/min. G.

(2) Amount of calcium deposited

MC3T3-E1 cells were seeded on the surface of the sterilized sample, VC was added to a final concentration of 5mM to a portion of the wells, and a portion of the sample was irradiated (peak wavelength 650nm, scintillation mode) for 20-30min/d using an LED lamp with a power of 3W. After incubation for 14d, the samples were washed 2 times with PBS and fixed for 15min by adding paraformaldehyde solution. Alizarin red, ARS, sigma-Aldrich was then added, incubated for 30min at 37 ℃, washed 3 times with pbs, and 500 μ L of Cetylpyridinium chloride (CPC, sigma-Aldrich) solution was added per well for evaluation of the amount of calcium deposited on the cells, and incubated for 15min at room temperature. OD of the supernatant at 590nm was measured using a microplate reader.

A and B in FIG. 6 are ALP activity and calcium deposition amount of the preosteoblasts after the culture on the material surface for 14d, respectively. Compared with the normal culture condition, the illumination improves ALP activity and calcium deposition amount of MC3T3-E1 cells on the Ti surface. Under red light irradiation, ALP activities of cells on the surface of different samples showed the following trends: mnO-C (VC) > MnO-C > MnO > Ti. Therefore, MC3T3-E1 cells on the surface of the MnO-C composite coating show better osteogenic differentiation capacity under the irradiation of red light.

Claims

1. The photoelectric response type manganese oxide-carbon composite coating is characterized in that the manganese oxide-carbon coating is a biological coating which is formed by loading a carbon material in situ on the surface of a manganese oxide nanosheet layer with a communicating pore structure, the carbon material wraps the surface of the manganese oxide nanosheet layer and is in close contact with manganese oxide so as to rapidly transfer photoelectrons generated by manganese oxide under the illumination condition, and at least part of the carbon material is a conductive carbon material; the mass ratio of carbon in the biological coating is 1-30%.

2. The photoelectric response type manganese oxide-carbon composite coating of claim 1, wherein the mass ratio of carbon in the biological coating is 5-25%.

3. The photo-electrically responsive manganese oxide-carbon composite coating according to claim 1, wherein said conductive carbon material is graphite and/or carbon nanotubes.

4. The photo-responsive manganese oxide-carbon composite coating of claim 1, wherein the manganese oxide nanosheets are formed of manganese oxide particles having a particle size of 0.01-2 μm, the nanosheets having a thickness of 1-30nm.

5. The photo-electric responsive manganese oxide-carbon composite coating according to claim 1, wherein the pore diameter of the communicating pores is 0.02 to 2 μm.

6. The preparation method of the photoelectric response type manganese oxide-carbon composite coating according to any one of claims 1 to 5, comprising the steps of:

(1) Preparing a manganese oxide coating by hydrothermal reaction: potassium permanganate is used as a manganese source, hydrochloric acid is used as a reducing agent, potassium chloride is used as a structural stabilizer, the raw materials are dissolved in deionized water to obtain a mixed solution, and then the mixed solution is used for in-situ growth of a manganese oxide sheet layer on the surface of a base material by adopting a hydrothermal reaction method; the hydrothermal reaction temperature is 80-180 ℃, and the hydrothermal reaction time is 0.5-24h;

(2) Preparing a composite coating by a high-temperature carbonization method: and (2) soaking the manganese oxide sheet layer prepared in the step (1) in a glucose solution for a period of time, and annealing at 200-600 ℃ for 1-4h in an argon atmosphere to obtain the photoelectric response type manganese oxide-carbon composite coating.

7. The method according to claim 6, wherein the base material comprises a medical metal material, and is at least one of pure titanium, titanium alloy, stainless steel or cobalt-chromium-molybdenum alloy.

8. The preparation method according to claim 6, wherein in the step (1), the concentration of potassium permanganate is 0.001-0.01mol/L, the concentration of hydrochloric acid is 1-5 times that of potassium permanganate, and the concentration of potassium chloride is 1-5 times that of potassium permanganate.

9. The method according to claim 6, wherein in the step (2), the concentration of the glucose solution is 0.1-2wt.%, and the soaking time is 2-48h.

10. Use of the photo-responsive manganese oxide-carbon composite coating of any one of claims 1 to 5 for nerve and bone tissue repair.