A nanomotor composite material with eccentric core-spiky shell structure and its preparation method and application

Abstract

The application discloses a kind of nanomotor composite material with eccentric core-echinus shell structure and its preparation method and application, the nanomotor composite material has core-shell structure, its core is made of carbon material, it is filled between core-shell by indocyanine green and staphylolytic enzyme material and is constituted, shell is SiO2@carbon material and is constituted, with echinus porous structure, and indocyanine green and staphylolytic enzyme are loaded on surface;The core of the shell does not coincide with the ball center.The nanomotor composite material of the application is irradiated under the NIR, and it is combined with photosensitizer ICG and carbon material in material, and its asymmetric eccentric structure can make composite material uneven heating, produce self-heating driving force, realize staphylolytic enzyme and ROS for MRSA biofilm targeted action.The nanomotor is applied to preparation of drug for promoting diabetic wound healing, has excellent tissue penetration capacity and drug efficiency, and shows efficient synergistic antibacterial performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a nanomotor composite material and a preparation method and application thereof, in particular to a nanomotor composite material with an eccentric core-spine shell structure and a preparation method and application thereof, and belongs to the technical field of antibacterial nanomaterial development. BACKGROUND

[0002] Diabetes mellitus (DM) is a chronic non-infectious disease caused by insulin secretion and utilization disorders, and DM trauma, especially foot ulcer, is common and serious, which is the main cause of non-traumatic amputation. Globally, 15-25% of DM patients will develop foot ulcers, and 85% of amputees have a history of foot ulcers, and the risk of amputation in DM patients is 10-20 times higher than that in non-DM patients. Due to low immune function and other factors, infected wounds heal slowly and may cause systemic complications. DM wounds are caused by a variety of pathogens, and chronic DM trauma is often infected with methicillin-resistant Staphylococcus aureus (MRSA), which has the characteristics of colonization, invasion, and strong drug resistance. About 15-30% of DM patients with foot ulcers may be infected with MRSA, and patients with frequent hospitalization, multiple antibiotic treatments, deep ulcers, and osteomyelitis are more susceptible to infection.

[0003] Currently, the treatment of DM trauma combined with infection mainly includes anti-infection, wound management, metabolic control, surgical intervention, and systemic support treatment, among which anti-infection is the key. However, due to DM trauma, especially long-term open ulcers, often accompanied by mixed infection of multiple pathogens, increasing the complexity of diagnosis and treatment; in addition, DM patients often have peripheral vascular disease, and insufficient blood supply to local tissues can reduce the antibiotic concentration at the infection site, weakening its bactericidal effect, and during the systemic application of antibiotics such as vancomycin and aminoglycosides, drug adverse reactions such as nephrotoxicity and intestinal flora imbalance are prone to occur, therefore, the anti-infection treatment of DM patients faces many challenges and treatment difficulties.

[0004] Biofilm is an extracellular matrix structure formed by stimulated bacteria, mainly composed of extracellular polysaccharides (EPS). Bacteria are connected through EPS, the surface bacteria can sense the environment, the deep bacteria are dormant, there are nutrient transport channels in the biofilm, and bacteria secrete EPS to adhere after adhering to the wound surface. However, the biofilm structure is strong and not easy to be removed by physical means, and can block the entry of antibiotics and immune factors. The negative charge structure in EPS can adsorb and neutralize antibiotics, and bacteria in the biofilm can also decompose the antibiotics that have penetrated into the inside, making the treatment of chronic wounds with biofilm and deep infections more difficult.

[0005] In recent years, lysozyme has attracted widespread attention due to its significant efficacy in destroying bacterial cell walls. Unlike traditional antibiotics, lysozyme is a naturally occurring antibacterial hydrolase in biological secretions such as saliva, tears, and mucus, and is an important part of the body's non-specific immune defense. Lysozyme mainly destroys the integrity of the bacterial cell wall by hydrolyzing peptidoglycan in the bacterial cell wall, leading to the rupture and death of bacterial cells, and has a unique advantage in the treatment of Gram-positive bacteria. In combination with antibiotic therapy, lysozyme can significantly enhance the penetration of antibiotics and improve the killing efficiency of bacteria, while reducing the body's antibiotic load and side effects. Moreover, due to its natural decomposition and metabolic properties, lysozyme is a safe and effective alternative for patients who require long-term antibacterial treatment and are intolerant or allergic to antibiotics. However, its clinical application is often limited by enzyme degradation, immunogenicity, bioavailability, and adverse reactions. Therefore, how to effectively improve its utilization and reduce side effects is the current challenge in the application of lysozyme.

[0006] Nanomaterials have been widely used in antibacterial therapy, but the antibacterial effect of nanomaterials depends on passive diffusion, lacks a targeting mechanism, and results in a decrease in effective concentration at the infection site. Moreover, given the presence of biofilms, ordinary nanomaterials can only stay on the surface of biofilms, and exhibit low antibacterial activity in the treatment of chronic wound infections, implant-related infections, and other biofilm-related diseases, while also increasing the risk of drug resistance in pathogenic bacteria.

[0007] Nanomotors are nanoparticles that can produce autonomous motion under driving force, and can be divided into endogenous and exogenous driven nanomotors according to their power sources. In antibacterial therapy, the mechanical force generated by nanomotors can destroy the biofilm matrix, and can also carry antibacterial drugs to release them inside the biofilm, improving the bactericidal efficiency and reducing the production of drug-resistant strains. Nanomotors can also achieve synergistic antibacterial therapy through surface modification. Now many researchers have achieved synergistic antibacterial therapy by modifying photosensitizers, magnetic materials, and active enzymes on the surface of nanomotors, and have successfully constructed some multifunctional integrated nanomotor antibacterial platforms, but there is a lack of research on targeted and efficient action against MRSA.

[0008] Photodynamic therapy (PDT) is a process in which a photosensitizer (PS) and oxygen interact to produce reactive oxygen species (ROS) under the irradiation of near-infrared (NIR) light, which plays an important role in various physiological processes. In wound healing, appropriate ROS can resist bacteria and promote angiogenesis, but high levels of ROS can cause oxidative stress, etc., leading to delayed healing. Therefore, in clinical treatment, how to reasonably regulate the production and action of ROS is particularly important. Indocyanine green (ICG) is a widely used photosensitizer (PS) with characteristics in the near-infrared region, which can achieve "diagnosis and treatment integration", has good biocompatibility and low phototoxicity risk, and has antibacterial effect in wound healing. However, free ICG has a short half-life and is prone to decomposition, and improving its utilization rate is a challenge in its application.

[0009] Therefore, it is urgent to develop a composite material with biological membrane permeability and high antibacterial activity for the preparation of a drug for treating DM wounds infected with MRSA. SUMMARY

[0010] In view of the problems in the prior art, a first object of the present application is to provide a nanomotor composite material with a special eccentric core-spine shell structure, which combines the photosensitizer ICG and carbon material in the material under the irradiation of NIR, and the asymmetric eccentric structure of the composite material can cause uneven heating, generating a self-heating driving force, and realizing the targeted action of lysozyme (Ly) and ROS on MRSA biofilm. The nanomotor has excellent tissue penetration ability and drug delivery efficiency, and exhibits high-efficiency synergistic antibacterial performance.

[0011] A second object of the present application is to provide a preparation method of a nanomotor composite material with an eccentric core-spine shell structure, which modifies the carbon-SiO2@carbon nanoparticles with an eccentric core-spine shell structure by aminopropyl modification, and loads ICG with photothermal effect and lysozyme with biofilm targeting property on the surface of the shell structure by using charge effect, thereby improving the loading capacity and overall antibacterial performance of the composite material.

[0012] A third object of the present application is to provide an application of a nanomotor composite material with an eccentric core-spine shell structure, which is applied to the preparation of a drug for promoting the healing of diabetic wounds. By combining photothermal, photodynamic and lysozyme, the nanomotor composite material is driven to move autonomously by near-infrared light, can specifically target MRSA biofilm, and exhibits significant synergistic effect in antibacterial, anti-inflammatory and tissue repair promotion. Moreover, the composite material of the present application can produce mild photodynamic effect when applied in cooperation with special NIR light treatment, thereby avoiding damage to normal tissues.

[0013] In order to achieve the above technical purposes, the present application provides a nanomotor composite material with eccentric core-prickle shell structure, which has a core-shell structure, the core is composed of carbon material, the core-shell is filled with indocyanine green and lysostaphin material, the shell is composed of SiO2@carbon material, has a prickle porous structure, and the surface is loaded with indocyanine green and lysostaphin; the core and the shell do not coincide with the spherical center.

[0014] The nanomotor composite material of the present application ingeniously combines the eccentric core-prickle shell structure and ICG, carbon material and Ly with photo-thermal effect and targeting property for MRSA biofilm, and improves the antibacterial performance of the nanomotor composite material through structure and composition synergy. Specifically, under the irradiation of NIR, the nanomotor composite material of the present application has photo-thermal effect due to ICG and carbon material constituting the core-shell structure matrix, but the intensity of the photo-thermal effect of the two is different: the photo-thermal effect of the shell with ICG and carbon material is the strongest; the photo-thermal effect of ICG filled between the core-shell is the second, and the photo-thermal effect of the carbon material of the eccentric core is the weakest, thereby causing uneven heating of the composite material, generating self-heating driving force, so that the composite material can move along the temperature gradient direction; when the drug contacts MRSA through self-heating driving in the application to prepare a drug for promoting diabetic wound healing, the Ly loaded on the surface of the nanomotor composite material and the internal Ly released through the prickle porous structure can target the destruction of the biofilm of MRSA, leading to the rupture and death of MRSA cells; in addition, under the irradiation of NIR, ICG in the composite material can generate a large amount of ROS, further strengthening the antibacterial and wound healing promotion.

[0015] The present application also provides a preparation method of the nanomotor composite material with eccentric core-prickle shell structure, which is that the carbon-SiO2@carbon nanoparticles with eccentric core-prickle shell structure are modified by surface grafting of aminopropyl to obtain aminopropylated carbon-SiO2@carbon nanoparticles; the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin are mixed to obtain the nanomotor composite material (CSIL) with eccentric core-prickle shell structure.

[0016] The preparation process of the carbon-SiO2@carbon nanoparticles with eccentric core-prickle shell structure is that aldehyde formaldehyde resin microspheres, resorcinol, formaldehyde and tetraethyl orthosilicate are subjected to reaction A to obtain nanosphere phenolic resin-SiO2@phenolic resin with core-shell structure; the phenolic resin-SiO2@phenolic resin is added with an etching agent to perform hydrothermal reaction to obtain partially etched phenolic resin-SiO2@phenolic resin nanosphere; and the partially etched phenolic resin-SiO2@phenolic resin nanosphere is carbonized to obtain the same.

[0017] In the technical scheme of the present application, firstly, in the process of reaction A, the polycondensation reaction of resorcinol and formaldehyde and the hydrolysis reaction of tetraethyl orthosilicate occur synchronously, so that the newly generated phenolic resin microspheres and silica are deposited on the surface of the original phenolic resin microspheres to form nanosphere phenolic resin-SiO2@phenolic resin (RF-SiO2@RF) with a core-shell structure, and then through the hydrothermal reaction and the etching effect of the etchant, the spiny porous structure is formed on the shell, and the cavity appears in the inside; in the carbonization process, due to the density difference between the core and the shell, the core structure in the inside becomes smaller, and under the action of gravity, the eccentric core structure is formed, and carbon-SiO2@carbon nanoparticles (C-SiO2@C) are obtained. Secondly, after the surface of the C-SiO2@C is modified by the aminopropyl, the material is positively charged, while the ICG is negatively charged, and the Ly is positively charged, and the two are sequentially loaded through the electrostatic effect, and at the same time, the ICG and the Ly can be filled in the cavity between the core and the shell through the porous structure, so that the load of the nanomotor can be significantly improved by the method of the present application.

[0018] As a preferred scheme, the phenolic resin microspheres are obtained by the polycondensation reaction of resorcinol, formaldehyde and water under the action of an alkaline catalyst. The solid-liquid ratio of resorcinol and formaldehyde is 0.3 g:(0.4-0.5) mL, and the reaction temperature is room temperature. The alkaline catalyst includes sodium hydroxide, potassium hydroxide and other commonly used bases.

[0019] As a preferred scheme, the process of surface grafting modification of aminopropyl is: after the carbon-SiO2@carbon nanoparticles are dispersed, (3-aminopropyl) triethoxysilane is added for grafting reaction; the dispersion is promoted by ultrasonic, and the dispersion solvent is ethanol.

[0020] As a preferred scheme, the solid-liquid ratio of the carbon-SiO2@carbon nanoparticles and (3-aminopropyl) triethoxysilane is 15 mg:(0.15-0.3) mL. The present application can comprehensively control the degree of aminopropyl by adjusting the solid-liquid ratio of the two, so as to facilitate the subsequent reaction. If the amount of (3-aminopropyl) triethoxysilane is too small, the degree of aminopropyl on the surface of the carbon-SiO2@carbon nanoparticles is insufficient, and the positive charge on the surface is insufficient, which will not only result in a smaller load of ICG and Ly, but also a part of the carbon-SiO2@carbon nanoparticles in the solution will be aggregated; and if the amount of (3-aminopropyl) triethoxysilane is too much, it may be attached to the surface of the nanoparticles, thereby affecting the pore structure of the nanoparticles.

[0021] As a preferred scheme, the conditions of surface grafting modification of aminopropyl are: the temperature is 50-60℃, and the time is 10-12h.

[0022] As a preferred scheme, the mass ratio of the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin is 2:(0.125-2):(0.125-2). The present application can comprehensively control the various performances of the nanomotor through the mass ratio of the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green (ICG) and lysostaphin (Ly). In terms of photosensitivity, when the amount of ICG is small, the amount of heat and reactive oxygen species (ROS) generated under near-infrared irradiation is reduced, and the light energy conversion efficiency is reduced; when the amount is large, the internal structure is unbalanced, which affects light propagation and conversion. In terms of antibacterial property, when the proportion of Ly is low, the ability to target and destroy MRSA biofilm is weak, and the antibacterial effect is poor; when the proportion is high, the stability of the nanomotor is affected, which indirectly affects the antibacterial property, and the content of ICG is also affected by the mass ratio, which further affects the amount of ROS generated and the antibacterial property. In terms of healing performance, the mass ratio affects the balance of the interaction between the components, and too high or too low proportion of ICG or Ly will break the balance and affect the overall performance of the nanomotor in wound healing.

[0023] As a preferred scheme, the mixing conditions are: stirring at room temperature for 24-48h. Further preferably, in the mixing process of the present application, the aminopropylated carbon-SiO2@carbon nanoparticles and ICG are mixed for 20-24h first, and then Ly is added and mixed for 20-24h. Through such a mixing method, it can be further ensured that ICG and Ly can be sequentially grafted on the carbon-SiO2@carbon nanoparticles through charge effect.

[0024] As a preferred scheme, the reaction A is carried out at room temperature for 5-6h, and the hydrothermal reaction is carried out at 70-80℃ for 0.5-2h, and the etchant includes Al(NO3)3 solution. By controlling the temperature and time during the hydrothermal reaction, the etching degree of the shell can be controlled under the action of the etchant to form a porous structure. The concentration of the etchant is 1-2mol / L, and the volume is 100-200mL. -1

[0025] As a preferred scheme, the carbonization is carried out at a temperature of 500-550℃ for 2-3h. Through carbonization, the phenolic resin can be changed into carbon material in the present application. If the carbonization temperature is too low or the time is too short, the carbonization cannot be completed; and if the carbonization temperature is too high, the material may be burned and deformed.

[0026] The present application also provides an application of the nanomotor composite material with eccentric core-spine shell structure. The nanomotor composite material is applied to the preparation of a drug for promoting the healing of diabetic wounds. By combining photothermal, photodynamic and lysostaphin, the nanomotor can be driven to move autonomously by near-infrared light, can specifically target MRSA biofilm, and shows a significant synergistic effect in antibacterial, anti-inflammatory and tissue repair promotion.​

[0027] As a preferred scheme, the medicine comprises the nanomotor composite material with eccentric core-spiny shell structure, physiological saline and excipients. The excipients include excipients commonly used in injection preparations, such as phosphate buffer, phenol, glucose and the like.

[0028] As a preferred scheme, the medicine is an injection preparation, and is further preferably a pharmaceutically acceptable local injection preparation. In the use process, the nanomotor composite material can be dispersed in physiological saline, and the obtained dispersion solution is administered by injection.

[0029] As a preferred scheme, the nanomotor composite material with eccentric core-spiny shell structure is not less than a pharmaceutically effective amount.

[0030] As a preferred scheme, the medicine has a photothermal effect, and infrared light is irradiated in the early stage of the medicine action process, and no infrared light is irradiated in the later stage. Through this special light irradiation, the nanomotor composite material can effectively release 1O2 to kill bacteria, and excessive ROS will not harm normal tissues, which is beneficial to the rehabilitation of diabetic wounds.

[0031] As a preferred scheme, the power of the infrared light irradiation is 0.3-1.2 W / cm 2 , and the time is 100-600 s.

[0032] Compared with the prior art, the technical scheme of the present application has the following beneficial technical effects:

[0033] 1) The nanomotor composite material provided by the present application has a special eccentric core-spiny shell structure. Under the irradiation of NIR, the asymmetric eccentric structure of the nanomotor composite material can make the composite material heat unevenly, generate a self-heating driving force, and realize the targeted action of Ly and ROS on MRSA biofilm. The nanomotor has excellent tissue penetration ability and drug delivery efficiency, and exhibits high-efficiency synergistic antibacterial treatment performance.

[0034] 2) The preparation method of the present application is simple, the reaction conditions are relatively mild, the cost is low, the application prospect is large, large-scale preparation can be carried out, and the load of ICG and Ly on the nanomotor can be significantly increased by the method.

[0035] 3) The nanomotor composite material of the present application is applied to the preparation of a medicine for promoting the healing of diabetic wounds. By combining photothermal, photodynamic and lysostaphin, the nanomotor composite material is driven to move autonomously by near-infrared light, can specifically target MRSA biofilm, and exhibits a significant synergistic effect in antibacterial, anti-inflammatory and tissue repair promotion.

[0036] 4) The material of the present application is applied to prepare a medicine for promoting the healing of diabetic wounds. In the process of action, the nano motor composite material produces mild photodynamic effect by early short-time NIR light irradiation and later non-NIR light irradiation, so as to effectively release 1O2 to kill bacteria and not produce too much ROS to harm normal tissues, which is beneficial to the rehabilitation of diabetic wounds. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The micro-morphology diagrams of CS and CSIL prepared in Example 1 of the present application, wherein, Figure 1 (a) and Figure 1 (b) are SEM diagrams of CS and CSIL, respectively; Figure 1 (c) and Figure 1 (d) are TEM diagrams of CS and CSIL, respectively; Figure 1 (e) ~ Figure 1 (j) are EDS scanning diagrams of CSIL.

[0038] Figure 2 The ultraviolet absorption spectra of ICG and Ly at different concentrations and the residual ICG and Ly in the solution after loading in Example 1 of the present application, wherein, Figure 2 (a) is the ultraviolet-visible spectrum of ICG at different concentrations and the residual ICG in the solution of CSIL in Example 1; Figure 2 (b) is the ultraviolet-visible spectrum of Ly at different concentrations and the residual Ly in the solution of CSIL.

[0039] Figure 3 The loading rate and Zeta potential determination of the nano motor composite material prepared in Example 1 of the present application, wherein, Figure 3 (a) is the loading rate of ICG and Ly on the CS nano motor; Figure 3 (b) is the Zeta potential of CS, CSI and CSIL.

[0040] Figure 4 The photothermal effect of CS, CSI and CSIL prepared in Example 1 of the present application; wherein, Figure 4 (a) is the temperature rise of CS (200 μg mL -1 ) under different power densities at the same concentration; Figure 4 (b) is the temperature rise of CSI (200 μg mL -1 ) under different power densities at the same concentration; Figure 4 (c) is the temperature rise of CSIL (200 μg mL -1 ) under different power densities at the same concentration; Figure 4 (d) is the temperature rise of CSIL at different concentrations under the power density of 1.2 Wcm -2 ; Figure 4(e) power density of 1.2 W cm -2 Temperature change of CS, CSI, and CSIL under the condition; Figure 4 (f) Figure 4 (h) Photothermal cycle curves of CS, CSI, and CSIL, respectively; Figure 4 (i) Plot of light exposure time vs. -ln0.

[0041] Figure 5 Absorbance of DPBF vs. time under near-infrared laser (808 nm) irradiation for Example 1 of the present application, wherein, Figure 5 (a) Absorbance change of CSI+NIR; Figure 5 (b) Absorbance change of CSIL+NIR.

[0042] Figure 6 Trajectory of CSIL nanomotor under different laser power irradiation for Example 1 of the present application.

[0043] Figure 7 Schematic diagram of Y-tube experiment used in the present application; wherein, Figure 7 (a) Schematic diagram of Y-tube principle, Figure 7 (b) Red fluorescence distribution at the bifurcation of Y-tube, Figure 7 (c) Comparison of red fluorescence accumulation of MRSA and E. coli at the end of Y-tube.

[0044] Figure 8 Combination of CSIL nanomotor prepared in Example 1 of the present application with MRSA and E. coli under confocal microscope.

[0045] Figure 9 Data of each group of bacterial colonies for Example 1 of the present application, wherein, Figure 9 (a) Representative spread plate of colonies isolated from each group of MRSA biofilm; Figure 9 (b) Number of colonies of each group of MRSA; Figure 9 (c) Survival rate of each group of MRSA, and n.s represents no significant statistical difference, ** represents p<0.01, and *** represents p<0.001. Wherein, the control group represents the blank control group with PBS added.

[0046] Figure 10 Scanning electron microscope image of MRSA biofilm destruction in each group of Example 1 of the present application.

[0047] Figure 11 Further application of materials in each group of Example 1 of the present application to prepare drugs for wound healing in mouse experiments, wherein, Figure 11(a) is the wound photo after 0, 4, 8, 12, 16 days of treatment with PBS, CS, CSI+NIR, CSIL, CSIL+NIR, Van, the scale is 8mm; Figure 11 (b) is the trace of wound healing of different treatment groups during 16 days of treatment; Figure 11 (c) is the percentage change of wound area of different treatment groups, *** represents P<0.001.

[0048] Figure 12 The flowchart for preparing the nanomotor composite material with eccentric core-spine shell structure in Example 1 of the application, wherein RFR represents RF-SiO2@RF, Etched RFR represents partially etched RF-SiO2@RF. DETAILED DESCRIPTION

[0049] The following examples are specifically described only for the preferred embodiments of the application, and do not limit the scope of the application, and the improvements made by those skilled in the art without departing from the application should be considered within the protection scope of the application.

[0050] Example 1

[0051] (1) Preparation of C-SiO2@C nanoparticles

[0052] A mixture of ultrapure water (20 mL), anhydrous ethanol (140 mL) and NaOH (1.0 mol L -1 , 10 mL) was placed in a 250 mL round-bottom flask. Then, resorcinol (0.3 g) and formaldehyde (0.42 mL) were added respectively, and stirred at room temperature for 6 h to obtain phenolic resin RF microspheres.

[0053] Next, tetraethyl orthosilicate (TEOS, 0.6 mL) was added to the above-mentioned round-bottom flask containing RF microspheres and stirred for 8 min, then resorcinol (0.8 g) and formaldehyde (1.12 mL) were added again, and stirred for 5 h. The precipitate was filtered and washed with ethanol and ultrapure water respectively for 3 times, and the product was dried at 60°C under vacuum for 12 h, so that a layer of RF and SiO2 compound was deposited on the surface of the RF microspheres obtained in the previous step, forming nanospheres RF-SiO2@RF with core-shell structure (core is RF, shell is RF+SiO2 mixture).

[0054] The prepared RF-SiO2@RF (100 mg) was added to Al(NO3)3(2.0 mol L -1, 100 mL) aqueous solution, transferred into a hydrothermal reactor, reacted at 80℃ for 2 h, cooled to room temperature, centrifuged, washed with water for 3 times, and dried at 60℃ under vacuum for 10 h to obtain the partially etched RF-SiO2@RF nanospheres.

[0055] Finally, the etched RF-SiO2@RF nanospheres were placed in a tube furnace and heated to 550℃ under nitrogen for 2 h for carbonization. Finally, C-SiO2@C (CS) nanoparticles with eccentric core-spiky shell structure were obtained.

[0056] (2) Preparation of CSIL nanomotors

[0057] To improve the loading performance of CS, the CS was surface-modified. CS (15 mg) was added into anhydrous ethanol (25 mL) and ultrasonicated for 30 min to ensure the complete dispersion of CS. Then, (3-aminopropyl)triethoxysilane (APTES, 0.15 mL) was added and stirred at 60℃ for 12 h. After the above reaction was cooled to room temperature, it was washed with ethanol for 3 times and dried at 50℃ to obtain the aminopropylated CS nanoparticles.

[0058] The aminopropylated CS (2 mg) and ICG (2 mg) were mixed in water (1 mL) and stirred at 25℃ for 24 h. After washing, the ICG-loaded CS nanoparticles (CS@ICG, CSI) were dried under vacuum at room temperature. Then, CSI (2 mg) and lysostaphin (Ly, 2 mg) were added into 1 mL of water and stirred overnight at room temperature. Finally, the CSI loaded with Ly was washed with water and dried under vacuum overnight to obtain the ICG and Ly co-loaded eccentric core-spiky shell structured nanomotor composite (CSIL).

[0059] To observe the surface morphology of CS and CSIL, SEM, TEM and EDS scanning were performed on the CS and CSIL prepared in Example 1, and the results are shown in Figure 1 . As shown in Figure 1 (a) and Figure 1 (b), CS and CSIL both have uniform spherical structure with a diameter of about 250 nm. As shown in Figure 1 (c) and Figure 1 (d), CS and CSIL both have eccentric core-spiky shell internal structure. After loading ICG and Ly, the surface of CSIL becomes rougher, but its overall structure does not change compared with CS. Figure 1 (e) ~ Figure 1 (j) show that C and Si elements are uniformly distributed in the core and shell, in addition, S and N elements contained in APTES, ICG and Ly are also present in the core and shell, which indicates that ICG and Ly are successfully loaded on the CS motor.

[0060] ICG and Ly (2, 1, 0.5, 0.25 and 0.125 mg mL -1 , respectively) were prepared with different concentration gradient, and their UV absorbance intensity was measured. Subsequently, 2 mg mL -1 of CSI and aminopropylated CS solution were prepared (i.e. under the conditions of Example 1), and after overnight stirring without washing. The unbound ICG and Ly, which remained in the solution, were determined by UV-Vis spectrophotometer to determine the loading amount. The results are shown in Figure 2 . As shown in Figure 2 (a) and Figure 2 (b), the characteristic absorption peaks of ICG and Ly were located at 800 nm and 280 nm, respectively, and the UV absorption peaks decreased with decreasing concentration. The residual ICG and Ly concentration in the solution was significantly reduced, indicating that ICG and Ly were successfully loaded on CS.

[0061] At the same time, 500 μg mL -1 of CS, CSI and CSIL solutions with the same concentration were prepared, and the Zeta potential of the samples was determined. The loading rate was determined by UV-Vis spectroscopy, and the loading rate of ICG and Ly was calculated to be 52% and 82%, respectively, according to the amount of ICG and Ly remaining in the supernatant (as shown in Figure 3 a). In addition, the Zeta potential of the surface-modified CS was 10.33 ± 0.23 mV, and the potential of CSI changed to -6.93 ± 0.29 mV after loading ICG. After loading the positively charged Ly, the potential of CSIL increased significantly to 11.72 ± 0.38 mV, again verifying the successful loading of ICG and staphylokinase on CS (as shown in Figure 3 b).

[0062] Thermal and photodynamic properties of CSIL nanomotor:

[0063] First, 200 μg mL -1 of CS, CSI and CSIL solutions were prepared, and near-infrared light (wavelength 808 nm) with different power densities (0.3, 0.6, 0.9 and 1.2 W cm -2 ) was used. The temperature change was recorded every 30 s using an infrared thermal imager until the temperature tended to be stable, and the results are shown in Figure 4 (a) to Figure 4 (c). When the power density was 1.2 W cm -2After 10 minutes of irradiation, the temperatures of CS and CSI increased from 25℃ to 31.3℃ and 41.2℃, respectively. When CSI was further loaded with Ly, its maximum temperature still reached 40.3℃, indicating that the Ly loading had virtually no effect on the photothermal performance of CSIL. Furthermore, the photothermal efficiency increased significantly with increasing power density, further optimizing the power density to 0.9–1.2 W / cm². -2 .

[0064] Secondly, at a fixed optical power density of 1.2 W / cm², -2 Evaluation of CS, CSI, and CSIL at different concentration gradients (0, 50, 100, and 200 μg / mL) under certain conditions -1 The temperature changes and irradiation time were both 10 minutes, and the results were as follows: Figure 4 (d). The figure shows that the photothermal properties of CSIL also exhibit concentration dependence; as the concentration increases, the maximum temperature of CSIL also increases.

[0065] Finally, to evaluate the photothermal stability of CS, CSI, and CSIL, a power density of 1.2 W / cm² was used. -2 200 μg mL of NIR laser were respectively irradiated -1 The nanomotor solution was irradiated for 5 minutes, then the NIR laser was turned off. After the aqueous solution cooled naturally for 5 minutes, the NIR laser was turned on again for another 5 minutes. This "on-off" cycle was repeated 5 times. The heating curve is shown below. Figure 4 (e) Photothermal cycle curve as shown Figure 4 (f)~ Figure 4 (h). As shown in the figure, CS, CSI, and CSIL all exhibited excellent photothermal stability and cyclicability in the photothermal cycling experiment.

[0066] The photothermal conversion efficiency of CSIL is calculated using the following formula:

[0067]

[0068] θ=(TT s ) / (T max -T s )

[0069] τ=-t / lnθ

[0070] hsmC p / τ

[0071] In the formula, η is the photothermal conversion efficiency (%); h is the heat transfer coefficient; and S is the surface area of ​​the container used (cm²). 2 );T max The highest temperature reached by the nanomotor after stabilization (40.3℃); T Sambient temperature (25 °C); I is the laser power density (1.2 W cm -2 ) of the NIR laser (808 nm) used; A 808 is the absorbance value (0.191) of the CSIL nanomotor (200 pg mL -1 ) at 808 nm under UV measurement; 0 is the dimensionless driving force temperature; t is the heat transfer time constant; t is the time (s) of the hydrogel during the cooling process; m is the mass of the nanomotor (0.5 g) at the time of measurement; C P is the heat capacity of water (4.2 J g -1 ). According to the formula and Figure 4 (i), the calculated t of the CSIL nanomotor is 171.08, and the calculated CSIL photo-thermal conversion efficiency η is 46.6%. The above results show that the CSIL nanomotor has a light power density and concentration dependence, and has excellent photo-thermal conversion performance and photo-thermal stability.

[0072] The production of 1O2by ICG under NIR irradiation can be detected using the DPBF probe, as it can react with 1O2to form internal peroxide, and the absorption peak of DPBF under UV is about 410 nm. To clarify the ability of CSI and CSIL to produce 1O2, 50 pL of a solution of DPBF fluorescent probe (1 mg mL -1 ) was added to 2.9 mL of a 50% ethanol solution, then 50 pL of CSI and CSIL with a concentration of 2 mg mL -1 was added, respectively. Under 808 nm near-infrared irradiation, the absorbance of the mixed solution at 410 nm was measured after irradiation for 0, 1, 2, 4, 6, 8, 10 and 12 min, respectively, and the results are shown in Figure 5 (a) and Figure 5 (b). As shown in Figure 5 (a), the typical absorption peak of the mixed solution at 410 nm gradually weakened over time after the addition of DPBF and CSI (200 pg mL -1 ), indicating efficient production of 1O2. In addition, as shown in Figure 5 (b), the ability of CSIL to produce 1O2remained unchanged compared to CSI, indicating that the loading of Ly had no effect on the photodynamic properties of the CSIL nanomotor.

[0073] Exploration of the motion performance of the CSIL nanomotor:

[0074] To detect the motion performance of the nanomotor, the motion trajectories of the CSIL nanomotor were recorded and observed using an inverted fluorescence microscope under different light intensity conditions, as shown in Figure 6As shown, without the use of laser irradiation, the CSIL nanomotor basically moves in place. It shows limited and irregular Brownian motion, and as the light intensity increases, the diffusion range of the nanomotor gradually expands, and the motion trajectory is obviously lengthened, with significant motion ability.

[0075] Exploration of the targeting performance of CSIL nanomotor:

[0076] In order to verify the targeting function of CSIL nanomotor to MRSA bacteria, Y-shaped tube experiment was carried out. The specific operation is as follows: the red dye RhB labeled CSIL was co-cultured with MRSA and E. coli for 1 h, and the above suspension was centrifuged at 600 rpm to remove the CSIL not combined with bacteria. Finally, the combination of CSIL with MRSA and E. coli was observed under laser confocal microscope. Y-shaped tube is composed of starting part of liquid storage chamber (I) and branch chambers (II) and (III), and also includes a main road and two road branches. 0.5% agarose gel was pre-implanted in (II) and (III) chambers to prevent bacteria from moving backward, and then 10 μL of MRSA and E. coli (108CFU mL -1 ) was added in (II) and (III) chambers respectively and cultured overnight, and then 50 μL RhB labeled CSIL (200 μg mL -1 ) solution was added and dispersed in the storage pool (I), and (I) area was irradiated using near-infrared light, and the red fluorescence in the channel and the fluorescence intensity in the storage layer (II) and (III) were observed using confocal microscope, and the results are as follows Figure 7 .

[0077] As shown in Figure 7 (a), the CSIL solution containing RhB dye was added dropwise to the inlet of Y-shaped tube (I), and MRSA (II) and E. coli (III) were pre-cultured at both ends of Y-shaped tube, and then NIR irradiation (808 nm) was used to drive the CSIL in (I) chamber. Under the confocal microscope, it can be seen that the red nanomotor is moving, and a large piece of red fluorescence is formed in the main road, and as the nanomotor moves to the bifurcation of Y-shaped tube, it can be observed that the fluorescence intensity of MRSA on the right upper side is obviously higher than that of E. coli on the right lower side Figure 7 (b)). And with the passage of time, obvious accumulation of CSIL fluorescence intensity can be seen in (II) chamber, while there is almost no fluorescence in (III) chamber Figure 7 (c)). But it can also be seen that a small part of the nanomotor also has a tendency to move to the right lower (III) chamber at the bifurcation of Y-shaped tube, which may be due to the inertia of the nanomotor.

[0078] To more intuitively demonstrate the targeting ability of CSIL nanomotors to MRSA, CSIL was co-cultured with bacteria. The specific procedures were as follows: Activated MRSA and E. coli were stained with STOY9 green fluorescent nucleic acid dye for 30 minutes, followed by washing the bacterial suspension with PBS until the supernatant was colorless to remove unstained bacteria. Simultaneously, CSIL was mixed with the red dye Rhodamine B (RhB) for 12 hours prior to the co-culture, followed by washing to remove unbound excess dye. The stained CSIL was then co-cultured with MRSA and E. coli for 1 hour. Approximately 10 μL of 0.5% agarose heated in a 60°C water bath was added to a glass slide, and after 5 minutes, approximately 1 μL of the bacterial suspension mixture was added. The binding of CSIL to bacteria was observed under a confocal laser microscope. The results are shown below. Figure 8 .

[0079] Depend on Figure 8 As shown, confocal microscopy revealed that the red fluorescent CSIL nanomotors bound to and overlapped with most of the green fluorescent MRSA, indicating that they bind to MRSA. However, there was almost no binding or overlap between the green fluorescent E. coli and the CSIL nanomotors, suggesting that CSIL does not specifically bind to E. coli.

[0080] The above results demonstrate that, compared to E. coli, CSIL has a specific targeting effect on MRSA through near-infrared propulsion, laying the foundation for subsequent targeted antibacterial treatment of MRSA and wound healing therapy for DM.

[0081] Investigation of the penetration performance of CSIL nanomotors into biological membranes:

[0082] To evaluate the effect of CSIL nanomotors on MRSA biofilm removal, a biofilm coating experiment was conducted. The specific procedure was as follows: 500 μL of MRSA bacterial suspension (10⁸ CFU / mL) was added to a 48-well plate. -1 After 24 hours, the medium was changed with TSB. After 48 hours of incubation, a biofilm formed. The upper layer of TSB medium for in vitro antibacterial experiments was discarded. Subsequently, 500 μL of PBS, CS, CSI, and CSIL solutions (200 μg / mL) were added to each well along the well wall. -1 Incubate in a constant temperature incubator for 4 hours, then irradiate with 808nm NIR (1.2W cm⁻¹). -2)10min or so, at the same time, using near-infrared monitoring hole plate temperature, to ensure that the temperature does not exceed 45℃, after irradiation again incubated for 2h. Then take out the hole plate, on the vortex instrument for shaking, shaking the biofilm completely dispersed. Take each group of bacteria and drug suspension 100 μL added to 96 well plates, take 20 μL stock solution added to 180 μL PBS for 1 order of dilution, then dilution. Take the diluted bacteria 100 μL placed in the solid agar plate, then evenly spread with a spreader, bacteria dry, the culture dish inverted, 37℃ incubator overnight culture, 16h after taking pictures and colony counting. The above experimental steps repeated three times or more, while using the following formula to calculate the corresponding bacterial survival rate of each group:

[0083] Bacterial survival rate (%) = each experimental group of surviving bacteria number / control group of surviving bacteria number (%)

[0084] The remaining biofilm agar plating and bacterial counting, as shown in Figure 9 The agar plate count results show that the group without NIR irradiation, PBS, CS, CSI group has a large number of colonies, the number is 1.40, 1.34, 1.31 x 108 CFU mL -1 , while the CSIL number of colonies significantly reduced, 4.16 x 107 CFU mL -1 . After the introduction of light, PBS and CS group of bacteria number is 1.34 and 1.28 x 108 CFU mL -1 , compared with the corresponding NIR treatment group, the number of bacteria has no obvious reduction. Compared with the CSI group, CSI + NIR group of bacteria number is 7.12 x 107 CFU mL –1 , there is a significant decrease in the number of bacteria (P < 0.01). The number of bacteria in the CSIL + NIR group is only 4.33 x 105 CFU mL –1 , far lower than other NIR groups (P < 0.001). At the same time, the survival rate of the colonies was calculated, found that whether using NIR or not, the control group and the CS group had no significant difference in antibacterial rate, compared with the 93.3% survival rate of the CSI group, the survival rate of the CSI + NIR group was about 51.1% (P < 0.01). Compared with the 29.6% survival rate of the CSIL group, the bacterial survival rate of the CSIL + NIR group was only about 0.31% (P < 0.001), significantly lower than the survival rate of other NIR treatment groups (P < 0.001). It is shown that the CSIL nanomotor has a significant bactericidal effect on MRSA under the driving of near infrared light Figure 9 c).

[0085] The silicon wafer was pre-placed in the 48-well plate, and MRSA bacterial solution was also added. After 48 h of culture, a biofilm was formed on the silicon wafer. The grouping and treatment were consistent with the steps of the coating experiment. After treatment, 200 μL glutaraldehyde (2.5%) was added to each well for overnight fixation. Subsequently, 200 μL of ethanol with different concentration gradients (10%, 30%, 50%, 70%, 90%, and 100%) were used for step-by-step dehydration, and 100% ethanol was used for dehydration twice, each time for 15 min. After dehydration, the samples were air-dried overnight, then sputter-coated, and observed under SEM for the morphology of the biofilm and photographed for preservation. The results are shown in Figure 10 .

[0086] As shown in Figure 10 , the spherical bacterial morphology of the control group and the CS group was complete, and the biofilm showed a complete structure of layer-by-layer stacking. When treated with CSI+NIR, the bacterial surface was slightly swollen, but no obvious bacterial fragments were observed, indicating that the biofilm was preliminarily dispersed. In the CSIL group and the CSIL+NIR group, a large number of cell death was observed, especially a large number of bacterial fragments were widely distributed in the CSIL+NIR group. The MRSA bacterial morphology was distorted and fragmented, and the multi-layer three-dimensional structure of the biofilm was basically disappeared. Based on the above results, it is more directly proved that CSIL has the ability to destroy the MRSA biofilm and bacterial structure in vitro.

[0087] Performance exploration of CSIL nanomotor composite material applied to the wound of DM mice combined with MRSA infection:

[0088] In order to avoid excessive ROS production, a cascade mild photodynamic therapy strategy was adopted, which divided the treatment into two steps: first, using near-infrared (NIR) continuous irradiation for 3 days on the wound, the ROS produced by ICG and Ly together removed the surface layer of the biofilm on the wound. Then, without NIR irradiation, the nanomotor can still remove the hidden bacteria in the deep biofilm under the targeting action of Ly, finally achieving the effect of MRSA biofilm eradication and promoting the healing of DM wound.

[0089] (1) Establishment of diabetic mouse model

[0090] The experimental animals used were 5-6 week old C57 mice, which were fed with standard experimental mouse feed. After one week of adaptive feeding, STZ (50 mg kg -1 ) was injected for 5 consecutive days. The mice were fasted for 12 h before each injection and for 2 h after injection. One week after injection, the fasting blood glucose was measured at 12 h, and the fasting blood glucose was greater than 11.1 mmol L -1 The DM mouse model was considered to be successful. All animal operation procedures strictly followed the guidelines and regulations issued by the Experimental Animal Center of Xiangya Medical College, Central South University.

[0091] (2) Establishment of a diabetic trauma mouse model of MRSA infection

[0092] After fixing the DM mice, shave their backs, taking care not to scratch the skin. Then, use a depilatory cream to remove the hair from the backs of the mice, leaving the skin completely bare. The next day, administer tribromoethanol (240 mg / kg). 1 Mice were anesthetized, and their backs were disinfected. A wound approximately 8 mm in diameter was created on the back of the mouse using a sterile biopsy puncture machine, and 50 μL of MRSA bacterial solution (10⁸ CFU / mL) was dripped onto the wound surface. 1 All surgical procedures were performed under sterile conditions. After 48 hours, a yellow membrane, known as the MRSA biofilm, was visible on the wound surface, indicating the successful establishment of MRSA-infected diabetic wound mice.

[0093] (3) Animal experimental grouping and treatment

[0094] Mice that successfully developed the model were divided into 6 groups (n=4 per group): PBS, CS, CSI+NIR, CSIL, CSIL+NIR, and vancomycin (Van) groups. For 3 consecutive days, the mice in the treatment groups were administered the drug (prepared by mixing physiological saline with PBS, CS, CSIL, and Van to form injectable formulations, respectively, at a dose of 25 mg / kg) via local injection. 1 In the CSI+NIR and CSIL+NIR groups, NIR irradiation (1.2W cm⁻¹) was administered immediately after drug administration for 10 min. 2 The PBS and Van groups received no further treatment after applying appropriate amounts of PBS and vancomycin to the wound. In the NIR treatment group, temperature changes were recorded using an infrared thermal imager during irradiation. Wounds were photographed on days 0, 4, 8, 12, and 16 of the treatment period, and mouse weight was recorded every other day. Mouse bedding was changed daily. The recorded wound area was measured and analyzed using image processing software. The relative wound area of ​​the mice was calculated using the following formula:

[0095] Relative wound area (%) = A W / A W0 ×100%

[0096] In the formula, A W The wound area of ​​mice at the corresponding number of days after treatment; A W0 The area of ​​the wound in the mouse before treatment.

[0097] The results are as follows Figure 11 As shown, Figure 11(a) The results showed that there was a layer of intact yellow MRSA biofilm on the wound surface of each group of mice before treatment, accompanied by exudation, indicating that the MRSA infected wound model was successfully established. At 0-3 days, treatment was given, and on the 4th day, the PBS and CS groups still had intact biofilm and exudation, and even the wound of the PBS group had a tendency to expand. The biofilm and exudation of the CSI+NIR group were slightly reduced, but the area of the wound biofilm did not change significantly. The biofilm and exudation of the CSIL group were reduced, and the most obvious change was in the CSIL+NIR group, where the yellow biofilm was largely dissolved on the 4th day, but there was still a small amount of exudation, and the exposed part of the red inflammatory tissue could be seen. The biofilm of the Van group still existed stubbornly on the 4th day. The biofilm of the CSI+NIR group and the Van group gradually thinned around the 8th day, but the wound area did not significantly decrease. On the 16th day of treatment, the wounds of the CSIL+NIR group had completely healed, and a small amount of new hair was visible. The biofilm of the PBS and CS groups was thicker and more stubborn than on the 0th day, and the CSI+NIR and Van groups still had some biofilm, and the wound healing was poor. The CSIL group still had a small amount of exudation on the wound surface around the 12th day, and showed partial healing around the 16th day.

[0098] In order to more intuitively show the healing situation, the wound surface was drawn and calculated using image software. The relative wound area ratio of the PBS group was 116%, and the area ratios of the CSI+NIR, CSIL, CSIL+NIR and Van groups were 57.8%, 33.2%, 2.8% and 44.3%, respectively, all with significant differences (all P<0.001). This indicates that each group has a certain effect on promoting wound healing, but compared with the 2.8% of the CSIL+NIR group, the relative wound area ratio of the other treatment groups is significantly higher than that of the CSIL+NIR group (all P<0.001). Figure 11 b and Figure 11 c), indicating that the effect of the other treatment groups on promoting wound healing is limited. The above results confirm that the CSIL nanomotor prepared to promote the application of diabetic wound healing has excellent biofilm removal and wound healing promotion in MRSA infected DM wound mice, and also confirms that the excellent performance of the nanomotor of the present application is due to the synergistic effect of the eccentric structure, ICG, Ly and NIR.

[0099] Example 2

[0100] The difference between this embodiment and embodiment 1 is only that the amount of Ly in step (2) is replaced by 1 mg, and the remaining steps and conditions are consistent. The prepared nanomotor (CSIL) material has the same morphological characteristics as embodiment 1, also has a core-shell structure of eccentric core-spiny shell, and also has the performances of self-heating driving and targeting MRSA, but because the amount of Ly is reduced, the antibacterial performance is reduced, the biofilm is largely dissolved at the 8th day, but the wound of the mouse is completely healed after 16 days of treatment.

[0101] Embodiment 3

[0102] The difference between this embodiment and embodiment 1 is only that the temperature of aminopropylization in step (2) is replaced by 50℃, and the amount of ICG is replaced by 1 mg, and the remaining steps and conditions are consistent. The prepared nanomotor (CSIL) material has the same morphological characteristics as embodiment 1, also has a core-shell structure of eccentric core-spiny shell, and also has the performances of self-heating driving and targeting MRSA, but because the amount of ICG is reduced, the difference in the photothermal effect intensity of each layer of the nanomotor composite material is reduced, the self-heating driving rate of the nanomotor is slowed down, but the overall performance is still much better than CS, PBS and Van.

Claims

1. A nanomotor composite material with eccentric core-spiky shell structure, characterized in that: The nanomotor composite material has a core-shell structure, the core of which is composed of carbon material, the space between the core and the shell is filled with indocyanine green and lysostaphin material, the shell is composed of SiO2@carbon material, has a spiny porous structure, and the surface is loaded with indocyanine green and lysostaphin; the core and the shell do not coincide with the center of the sphere; The preparation process of the nanomotor composite material is as follows: carbon-SiO2@carbon nanoparticles with eccentric core-spiny shell structure are modified by surface grafting of aminopropyl to obtain aminopropylated carbon-SiO2@carbon nanoparticles; the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin are mixed to obtain the nanomotor composite material with eccentric core-spiny shell structure; The mass ratio of the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin is 2: (0.125-2): (0.125-2). The nanomotor composite material is applied to the preparation of a drug for promoting the healing of diabetic wounds based on MRSA infection.

2. The method of claim 1, wherein the nanomotor composite material having eccentric core-spiny shell structure is prepared by the following steps: (1) preparing a core material; (2) preparing a spiny shell material; (3) preparing a nanomotor composite material by mixing the core material and the spiny shell material. The preparation process of the nanomotor composite material is as follows: carbon-SiO2@carbon nanoparticles with eccentric core-spiny shell structure are modified by surface grafting of aminopropyl to obtain aminopropylated carbon-SiO2@carbon nanoparticles; the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin are mixed to obtain the nanomotor composite material with eccentric core-spiny shell structure; The preparation process of the carbon-SiO2@carbon nanoparticles with eccentric core-spiny shell structure is as follows: aldehyde formaldehyde resin microspheres, resorcinol, formaldehyde and tetraethyl orthosilicate are subjected to reaction A to obtain nanospheres of phenolic aldehyde resin-SiO2@phenolic aldehyde resin with a core-shell structure; the phenolic aldehyde resin-SiO2@phenolic aldehyde resin is added with an etching agent and subjected to hydrothermal reaction to obtain partially etched nanospheres of phenolic aldehyde resin-SiO2@phenolic aldehyde resin; the partially etched nanospheres of phenolic aldehyde resin-SiO2@phenolic aldehyde resin are subjected to carbonization to obtain the carbon-SiO2@carbon nanoparticles with eccentric core-spiny shell structure; The mass ratio of the aminopropylated carbon-SiO2@carbon nanoparticles, indocyanine green and lysostaphin is 2: (0.125-2): (0.125-2).

3. The method for preparing a nanomotor composite material with an eccentric core-spiny shell structure according to claim 2, characterized in that: The phenolic aldehyde resin microspheres are obtained by polycondensation reaction of resorcinol, formaldehyde and water under the action of an alkaline catalyst.

4. The method of claim 2 or 3, wherein the method further comprises: The process of surface grafting modification of aminopropyl is as follows: the carbon-SiO2@carbon nanoparticles are dispersed and then (3-aminopropyl) triethoxysilane is added for grafting reaction; The solid-liquid ratio of the carbon-SiO2@carbon nanoparticles and (3-aminopropyl) triethoxysilane is 15 mg: (0.15-0.3) mL.

5. The method for preparing a nanomotor composite material with an eccentric core-spiny shell structure according to claim 4, characterized in that: The conditions for surface grafting modification of aminopropyl are as follows: the temperature is 50-60°C, and the time is 10-12 h.

6. The preparation method of the nanomotor composite material with eccentric core-spiny shell structure according to claim 2, characterized in that: The mixing conditions are as follows: stirring at room temperature for 24-48 h.

7. The method for preparing a nanomotor composite material with an eccentric core-spiny shell structure according to claim 2, characterized in that: The conditions for reaction A are as follows: the temperature is room temperature, and the reaction time is 5-6 h; The conditions for hydrothermal reaction are as follows: the temperature is 70-80°C, the time is 0.5-2 h, and the etching agent includes Al(NO3)3 solution; The conditions for carbonization are as follows: the temperature is 500-550°C, and the time is 2-3 h.

8. Use of a nanomotor composite material having an eccentric core-spiky shell structure according to claim 1, characterized in that: The application is applied to the preparation of a medicine for promoting the healing of a diabetic wound based on MRSA infection.

9. Use of a nanomotor composite material having an eccentric core-spiky shell structure according to claim 8, characterized in that: The medicine comprises a nanomotor composite material with an eccentric core-spine shell structure, physiological saline and excipients.

10. Use of a nanomotor composite material having an eccentric core-spiky shell structure according to claim 8 or 9, characterized in that: The medicine has a photothermal effect, and infrared light is used for irradiation in the early stage of the medicine action process, and no infrared light is used for irradiation in the later stage.

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