Mesoporous core-shell structure nanoscale enzyme with multiple enzyme activities and preparation method and application thereof

Abstract

The present application relates to the technical fields of nanomedicine and functional nanomaterials, and discloses a mesoporous core-shell structure nanoenzyme with multiple enzyme activities as well as a preparation method and application thereof, the nanoenzyme takes gold nanorods as an inner core and iridium and its oxide as an outer shell, the outer shell is modified by polyethylene glycol and then loaded with a photosensitizer chlorin e6 to form an AuNR@Ir / IrO2-PEG / Ce6 nanoenzyme, the nanoenzyme has high catalase (CAT) activity, can decompose hydrogen peroxide (H2O2) in a tumor microenvironment and generate oxygen (O2) in situ, effectively improves the treatment effect of photodynamic therapy (PDT), and through the synergistic effect of photodynamic therapy (PDT) and photothermal therapy (PTT) combined with photoacoustic imaging function, provides a brand-new diagnosis and treatment integrated solution for efficient treatment and microenvironment regulation of tumors, and effectively makes up for the defects of insufficient enzyme activity and low photothermal conversion efficiency of the prior art.

Description

Technical Field

[0001] This invention belongs to the field of nanomedicine and functional nanomaterials technology, specifically relating to mesoporous core-shell structured nanozymes with multi-enzyme activity, their preparation methods, and applications. Background Technology

[0002] In recent years, the development of nanomedicine has provided new strategies for the diagnosis and treatment of tumors. Photothermal therapy (PTT), photodynamic therapy (PDT), and photoacoustic imaging (PAI) have become hot topics in integrated tumor diagnosis and treatment research. Among them, gold nanorods have shown great potential in PTT and PAI due to their excellent photothermal conversion efficiency, but their therapeutic efficacy is greatly limited by the laser's penetration ability in biological tissues. The efficacy of photodynamic therapy (PDT) is limited by the inherent hypoxic microenvironment of the tumor, a bottleneck that significantly weakens its therapeutic effect. Single treatment methods are no longer sufficient to meet the needs of tumor treatment; multimodal integrated diagnosis and treatment has become a development trend.

[0003] Nanozymes, possessing activities similar to peroxidase (POD), oxidase (OXD), and catalase (CAT), are widely used to regulate the tumor microenvironment. Among these, CAT-like enzymes can catalyze the decomposition of high concentrations of hydrogen peroxide (H2O2) within the tumor into oxygen, effectively alleviating hypoxia and providing a sufficient oxygen source for photodynamic therapy. However, currently common nanozymes still have shortcomings in catalytic efficiency and stability, and their limited functionality makes it difficult to simultaneously meet the needs of imaging and therapy.

[0004] Therefore, the current field of tumor diagnosis and treatment urgently needs a new nanotechnology that can simultaneously solve the following technical problems: how to overcome the limitations of laser tissue penetration on phototherapy, how to efficiently improve the hypoxic microenvironment of tumors to enhance the efficacy of phototherapy, and how to achieve the synergistic integration of catalytic regulation, photothermal therapy, photodynamic therapy and photoacoustic imaging functions. Summary of the Invention

[0005] This invention utilizes the abundant mesoporous structure of iridium nanoclusters to load the photosensitizer dihydroporphyrin E6 (Ce6). The AuNR@Ir / IrO2-PEG / Ce6 nanozyme prepared in this invention exhibits highly efficient CAT activity, which can decompose H2O2 in the tumor microenvironment to provide the necessary O2, thus enhancing the therapeutic effect of PDT. Furthermore, it provides a novel integrated solution for efficient tumor treatment and microenvironment regulation through PDT combined with PTT and photoacoustic imaging, overcoming the shortcomings of existing technologies.

[0006] On one hand, the present invention provides a mesoporous core-shell nanozyme with multi-enzyme activity. The nanozyme has a core-shell structure with gold nanorods as the core and an outer shell composed of iridium and its oxides. The outer shell has a mesoporous structure and loads the photosensitizer dihydroporphyrin E6 through the mesoporous structure.

[0007] On the other hand, the present invention provides a method for preparing the above-mentioned mesoporous core-shell structured nanozyme with multi-enzyme activity, wherein the steps of the preparation method are as follows:

[0008] Preparation steps of gold nanorods: Gold nanorods are prepared by seed-mediated method; gold nanorods are dispersed in dispersion medium to obtain gold nanorod dispersion;

[0009] The coating steps for gold nanorods are as follows: a hexadecyltrimethylammonium chloride solution is added to a gold nanorod dispersion to obtain a mixed solution; an iridium trichloride solution is added to the mixed solution and a hydrothermal reaction is carried out to obtain a core-shell structure of gold nanorods@iridium nanoclusters; the core-shell structure of gold nanorods@iridium nanoclusters is purified and template removed to obtain iridium nanoclusters-coated gold nanorod nanozymes (AuNR@Ir / IrO2).

[0010] Polyethylene glycol modification steps: Iridium nanoclusters coated with gold nanorod nanozymes are added to an amino polyethylene glycol solution to obtain a polyethylene glycol modification reaction system; the polyethylene glycol modification reaction system is reacted, and the precipitate is collected after the reaction is completed to obtain polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozymes (AuNR@Ir / IrO2-PEG).

[0011] Photosensitizer loading steps: Polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozymes were dispersed in water to obtain a polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozyme solution; dihydroporphyrin E6 was added to the polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozyme solution to obtain a photosensitizer loading system; the photosensitizer loading system was reacted under light-protected conditions, and the precipitate was collected after the reaction to obtain a mesoporous core-shell structured nanozyme with multi-enzyme activity (AuNR@Ir / IrO2-PEG / Ce6).

[0012] Further, in the preparation steps of gold nanorods, the step of preparing gold nanorods via a seed-mediated method includes: using chloroauric acid solution as a precursor, preparing a seed solution under the action of a strong reducing agent and a surfactant; growing gold nanorods in the seed solution under the action of a surfactant, a morphology modifier, a weak reducing agent, and chloroauric acid solution to obtain a crude gold nanorod solution; wherein the strong reducing agent includes sodium borohydride solution; the surfactant includes hexadecyltrimethylammonium bromide solution; the morphology modifier includes silver nitrate solution; and the weak reducing agent includes 3-aminophenol solution.

[0013] In the preparation steps of gold nanorods, dispersing gold nanorods in a dispersion medium includes: centrifuging a crude gold nanorod solution to collect the precipitate, washing the precipitate with water, and then dispersing the precipitate in a dispersion medium to obtain a gold nanorod dispersion; the dispersion medium includes deionized water.

[0014] Furthermore, in the gold nanorod coating step, the mass ratio of gold nanorods to hexadecyltrimethylammonium chloride in the mixed solution is 1:50-1:100; and the final concentration of hexadecyltrimethylammonium chloride in the mixed solution is 0.04-0.08M.

[0015] Furthermore, in the gold nanorod coating step, the volume ratio of the iridium trichloride solution to the mixed solution is 1:25; and the concentration of the iridium trichloride solution is 0.05M.

[0016] Furthermore, in the coating step of gold nanorods, the hydrothermal reaction after adding iridium trichloride solution to the mixed solution includes: after adding iridium trichloride solution to the mixed solution, stirring is first used to make iridium ions uniformly adsorbed on the surface of gold nanorods, and then the temperature is raised to 230℃-250℃ and the reaction is carried out for 1-3 hours to promote further crystallization and uniform coating of iridium nanoclusters.

[0017] Furthermore, in the step of coating gold nanorods with iridium nanoclusters, the purification and template removal of the core-shell structure of the gold nanorods@iridium nanoclusters includes: washing the core-shell structure of the gold nanorods@iridium nanoclusters in ethanol to remove unreacted substances and residual surfactants on the surface of the core-shell structure of the gold nanorods@iridium nanoclusters, obtaining a washed precipitate; then dispersing the washed precipitate in an ammonium nitrate ethanol solution and heating it under reflux to remove residual surfactants inside the pores of the gold nanorods@iridium nanoclusters.

[0018] Furthermore, in the step of coating gold nanorods with iridium nanoclusters, the concentration of the ammonium nitrate ethanol solution is 2 g / L; the reflux heating temperature is 80℃ and the time is 24 h.

[0019] Furthermore, in the polyethylene glycol modification step, the mass ratio of the gold nanorod nanozyme coated with iridium nanoclusters to amino polyethylene glycol in the polyethylene glycol modification reaction system is 1:25-1:50, and the mass concentration of the amino polyethylene glycol is 2.5 mg / mL.

[0020] Furthermore, in the Ce6 loading step, the mass ratio of the polyethylene glycol-modified iridium nanoclusters-coated gold nanorod nanozyme to the photosensitizer dihydroporphyrin E6 in the photosensitizer loading system is 1:2-1:5; the amount of photosensitizer dihydroporphyrin E6 added to the polyethylene glycol-modified iridium nanoclusters-coated gold nanorod nanozyme solution is 5 mg.

[0021] On the other hand, the present invention provides the application of the above-mentioned mesoporous core-shell structured nanozyme with multi-enzyme activity in the preparation of photosensitizers that induce tumor death.

[0022] Furthermore, the application involves a mesoporous core-shell nanozyme with multi-enzyme activity catalyzing the conversion of oxygen in the tumor microenvironment into singlet oxygen under laser irradiation, thereby inducing tumor cell apoptosis or necrosis through the oxidative damage of singlet oxygen.

[0023] The technical solution of this invention has the following advantages:

[0024] 1. The AuNR@Ir / IrO2-PEG / Ce6 nanozyme of this invention, utilizing its unique AuNR@Ir / IrO2 core-shell structure and highly active surface constructed from sub-nanometer iridium clusters, exhibits a significant advantage by simultaneously possessing triple biomimetic catalytic activities resembling catalase (CAT), peroxidase (POD), and oxidase (OXD). In the CAT reaction, this nanozyme exhibits a low Km and extremely high kcat, enabling rapid and efficient decomposition of H2O2 and continuous oxygen production. In the POD reaction, it demonstrates ultra-high affinity for the substrate, with a catalytic efficiency (kcat / Km) approaching the diffusion limit, significantly superior to traditional metal oxide and noble metal nanozymes. It also exhibits stable oxidation capabilities in the OXD reaction. The synergistic effect of these multiple enzymes significantly enhances its ability to regulate oxygen metabolism and promote reactive oxygen species (ROS) generation in the tumor microenvironment, providing a continuous oxygen source for photodynamic therapy and improving overall therapeutic efficacy.

[0025] 2. The nanozyme described in this invention has a high photothermal conversion efficiency (up to 46.3%), can achieve significant tumor ablation effects under near-infrared light irradiation, and exhibits excellent photothermal stability. Its efficient photothermal conversion not only helps to increase the temperature, thereby further enhancing the catalytic activity of the nanozyme, but also endows it with stronger photoacoustic imaging capabilities, enabling real-time monitoring and integrated diagnosis and treatment of tumors.

[0026] 3. The nanozyme described in this invention can efficiently decompose excess H2O2 in the tumor microenvironment to generate oxygen, thereby effectively alleviating the hypoxic state commonly found in tumor tissue and improving the tumor microenvironment. In this process, not only is the risk of oxidative damage from H2O2 reduced, but a continuous oxygen supply is also provided for the photosensitizer's role in photodynamic therapy, significantly improving the generation efficiency of reactive oxygen species (ROS) and substantially enhancing the efficacy of photodynamic therapy. Therefore, this invention achieves a synergistic effect of regulating the tumor microenvironment through nanozyme catalysis and enhancing photodynamic therapy, demonstrating significant therapeutic advantages and application potential. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention.

[0028] Figure 1 High-angle annular dark-field scanning transmission (HAADF-STEM) and energy-dispersive X-ray spectral mapping (EDS) are shown for AuNR@Ir / IrO2 nanozymes.

[0029] Figure 2 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the AuNR@Ir / IrO2 nanozyme.

[0030] Figure 3 The graph shows the photothermal conversion efficiency of AuNR@Ir / IrO2-PEG nanozymes.

[0031] Figure 4 The figure shows the steady-state kinetic analysis results of the catalase-like catalytic activity of AuNR@Ir / IrO2-PEG / Ce6 nanozyme, including the Michaelis equation curve (V–[S] curve) and the Lineweaver–Burk double reciprocal curve (1 / V–1 / [S] curve).

[0032] Figure 5 The graph shows the steady-state kinetic analysis results of the peroxidase-like catalytic activity of AuNR@Ir / IrO2-PEG / Ce6 nanozyme with H2O2 as the substrate, including the Michaelis-Menten equation curve (V–[S] curve) and the Lineweaver–Burk double reciprocal curve (1 / V–1 / [S] curve).

[0033] Figure 6 The graph shows the steady-state kinetic analysis results of the peroxidase-like catalytic activity of AuNR@Ir / IrO2-PEG / Ce6 nanozyme with TMB as the substrate, including the Michaelis-Menten equation curve (V–[S] curve) and the Lineweaver–Burk double reciprocal curve (1 / V–1 / [S] curve).

[0034] Figure 7 The effect of introducing different gases on the rate of TMB catalytic oxidation reaction was investigated.

[0035] Figure 8 Photoacoustic images of a cross-section of the mouse abdomen and an in situ tumor in the liver.

[0036] Figure 9 The tumor volume changes in mice from different experimental groups during the 18-day treatment period. Detailed Implementation

[0037] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0038] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0039] Experimental materials used in the examples:

[0040] Sodium borohydride (NaBH4): powder ≥ 98.0%, Sigma-Aldrich;

[0041] Hexadecyltrimethylammonium bromide (CTAB): 99% biotechnology grade, McLean;

[0042] Chloroauric acid (HAuCl4): Au≥48%, Maclean;

[0043] Silver nitrate (AgNO3): 99.9999% trace metals basis, Sigma-Aldrich;

[0044] 3-Aminophenol: 98%, McLean;

[0045] Hexadecyltrimethylammonium chloride (CTAC): 99% biotechnology grade, McLean;

[0046] Iridium trichloride (IrCl3): 99.8% trace metals basis, Sigma-Aldrich;

[0047] Amino-based polyethylene glycol (mPEG-NH2): R-1001-2K, Ruixibio;

[0048] Dihydroporphyrin E6 (Ce6): 94% (HPLC), Adamas;

[0049] Example 1: Specific preparation steps of iridium nanoclusters coated with gold nanorod nanozymes.

[0050] This embodiment provides an iridium nanocluster-coated gold nanorod nanozyme, and the preparation process of the iridium nanocluster-coated gold nanorod nanozyme is as follows:

[0051] 1. Preparation of gold nanorods:

[0052] (1) Preparation of seed liquid:

[0053] First, preheat the water bath to 40°C, and prepare a 50mL centrifuge tube. Add pure water and refrigerate at 4°C for later use. At the same time, clean the 40mL sample bottle and stirring rotor, and dry them with hot air or in an oven for later use.

[0054] Subsequently, 10 mg of sodium borohydride (NaBH4) was weighed and dissolved in cold pure water at 4°C to prepare a NaBH4 solution with a final concentration of 0.01 M. The solution was then refrigerated to prevent decomposition. 0.3553 g of hexadecyltrimethylammonium bromide (CTAB) was weighed, added to 9.75 mL of pure water, and placed in a 40 mL sample vial. After melting the CTAB by hot air heating, the solution was placed in a 30°C water bath and stirred until completely transparent, thus obtaining the CTAB solution.

[0055] Add 0.15 mL of 0.01 M chloroauric acid (HAuCl4) solution to the CTAB solution while stirring to bring the final concentration of chloroauric acid in the reaction system to 0.15 mM, and continue stirring for 10 min. Then, rapidly add 0.2 mL of NaBH4 solution pre-cooled to 4 °C under vigorous stirring, continue stirring for 10 min, and then stop stirring. Place the system in a 40 °C water bath and let it stand for 2 h to obtain the gold seed solution.

[0056] (2) Growth of gold nanorods:

[0057] Clean and dry a 100mL flask, weigh 3.0249g of CTAB, add 83mL of pure water, and stir in a 30℃ water bath until the solution is completely transparent to obtain the CTAB solution.

[0058] Subsequently, 5 mL of 0.01 M chloroauric acid solution and 8 mL of 0.01 M silver nitrate (AgNO3) solution were added sequentially to the CTAB solution to obtain a mixed solution with a final concentration of silver nitrate of 0.8 mM. The mixture was stirred for 10 min. Then, 4 mL of 0.1 M 3-aminophenol solution was added to the mixed solution to achieve a final concentration of 4 mM. At this point, the mixed solution gradually became transparent. After 5 min, 1 mL of the gold seed solution prepared in step (1) was added, and stirring was continued for 2 min before stopping to obtain the reaction system. The reaction system was then reacted in a water bath at 40 °C under light-shielding conditions for 12 h. The resulting solution was the crude gold nanorod solution.

[0059] (3) Purification treatment:

[0060] The crude gold nanorod solution prepared in step (2) was evenly divided into three 50 mL centrifuge tubes and centrifuged at 11000 r / min for 20 min. The supernatant was discarded to obtain the precipitate. 40 mL of pure water was added to the precipitate for resuspending. After repeating the centrifugation and washing once, the precipitates from the three tubes were combined and diluted to 50 mL with pure water to obtain the purified gold nanorod (AuNR) dispersion.

[0061] 2. Preparation of gold nanorods coated with iridium nanoclusters:

[0062] (1) Preparation of precursor solution:

[0063] Take 10 mL of the gold nanorod dispersion prepared in the preparation step of gold nanorod and add it to 10 mL of a solution containing 0.1 M hexadecyltrimethylammonium chloride (CTAC). Place the solution on a magnetic stirrer and stir for 15 min to mix it thoroughly and evenly to obtain a mixed solution.

[0064] (2) Introduction and reaction of iridium precursor:

[0065] 1 mL of 0.05 M iridium trichloride (IrCl3) solution was added to the mixed solution prepared in step (1) under stirring conditions, and stirring was continued for 15 min to ensure that iridium ions were uniformly adsorbed on the surface of gold nanorods. The mixed solution was then transferred to a reaction vessel at 250 °C and reacted for more than 1 h to induce the reduction and cluster formation of iridium ions and uniform coating. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain the core-shell structure of gold nanorods@iridium nanoclusters.

[0066] (3) Purification and template removal of the product:

[0067] An appropriate amount of ethanol was added to the core-shell structure of the gold nanorods@iridium nanoclusters prepared in step (2), and the mixture was washed twice by centrifugation at 10000 r / min to remove unreacted substances and residual surfactants on the surface, resulting in a washed precipitate. The washed precipitate was redispersed in a 2 g / L ammonium nitrate ethanol solution and refluxed in an 80℃ water bath for 24 h to fully remove residual CTAC inside the pores, resulting in the reflux-heated product.

[0068] (4) Collection and preservation of products:

[0069] After the reflux heating is completed, the ethanol solvent in the reflux heating product prepared in step (3) is removed by centrifugation, and the resulting precipitate is collected. The precipitate is the gold nanorod nanozyme coated with iridium nanoclusters (hereinafter referred to as AuNR@Ir / IrO2 nanozyme), which is stored in a refrigerator at 4°C for later use.

[0070] 3. Polyglycolation and loading of photosensitizer Ce6:

[0071] (1) Polyethylene glycol modification:

[0072] Two mg of AuNR@Ir / IrO2 nanozyme, prepared by the step of coating gold nanorods with iridium nanoclusters, was added to 20 mL of an aqueous solution of amino polyethylene glycol (mPEG-NH2) with a mass concentration of 2.5 mg / mL. The solution was sonicated for 5 min to promote thorough dispersion and facilitate contact with the reactants, followed by magnetic stirring at room temperature. After the reaction was complete, the mixture was separated by low-speed centrifugation, the supernatant was discarded, and the precipitate was collected to obtain a polyethylene glycol-modified iridium nanocluster-coated gold nanorod nanozyme (hereinafter referred to as AuNR@Ir / IrO2-PEG nanozyme).

[0073] (2) Loading of photosensitizer Ce6:

[0074] The obtained AuNR@Ir / IrO2-PEG nanozyme was redispersed in 10 mL of deionized water, and 5 mg of photosensitizer dihydroporphyrin E6 (Ce6) was added to the system. The reaction was carried out overnight (approximately 12 h) under light-protected conditions with magnetic stirring to achieve sufficient adsorption and loading of Ce6 molecules. After the reaction was completed, the unloaded free Ce6 molecules were removed by two centrifugation washes, and the precipitate was collected to obtain a mesoporous core-shell nanozyme with multi-enzyme activity (hereinafter referred to as AuNR@Ir / IrO2-PEG / Ce6 nanozyme) suitable for in vivo experiments.

[0075] AuNR@Ir / IrO2-PEG / Ce6 nanozymes exhibit excellent dispersibility and physiological stability, significantly improving the material's biocompatibility and in vivo circulation stability. The successful loading of Ce6 endows the nanozyme with photodynamic therapy (PDT) functionality, enabling it to generate reactive oxygen species (ROS) under light irradiation. This achieves synergistic therapy with the nanozyme's catalytic activity and photothermal effects, providing a highly efficient platform for multimodal tumor diagnosis and treatment.

[0076] Experimental Example 1: Morphological characterization and XPS analysis of AuNR@Ir / IrO2 nanozymes.

[0077] like Figure 1 The image shown is a high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of the AuNR@Ir / IrO2 nanozyme prepared in this invention. Figure 1 As can be seen, the obtained AuNR@Ir / IrO2 nanozyme exhibits a rod-like structure with a length of approximately 180 nm and a diameter of approximately 50 nm, displaying uniform morphology and good dispersibility. A gold nanorod (AuNR) core is clearly visible in the center, with a uniform outer layer of iridium and its oxide nanoclusters, indicating that iridium and its oxides have been successfully grown on the surface of the gold nanorods, forming a typical core-shell structure.

[0078] Further X-ray photoelectron spectroscopy (XPS) analysis revealed that iridium on the sample surface exists primarily in the forms of elemental Ir (0 valence) and IrO2 (+4 valence), confirming that the AuNR@Ir / IrO2 nanozyme surface simultaneously possesses both metallic iridium and iridium oxide chemical states, providing a structural basis for its excellent catalytic performance. Figure 2 ).

[0079] Experimental Example 2: Photothermal Performance Analysis of AuNR@Ir / IrO2-PEG Nanozymes.

[0080] Take 0.2 mL of a deionized water dispersion containing AuNR@Ir / IrO2-PEG nanozyme at a concentration of 100 μg / mL and place it in a centrifuge tube for later use. Use a continuous laser with a wavelength of 1064 nm as the light source, at a power density of 0.6 W / cm². 2 The sample was irradiated under the specified conditions for 5 minutes, and the temperature change of the sample was recorded.

[0081] During laser irradiation, the sample temperature gradually increased and reached its maximum temperature at approximately 5 minutes. The laser was then turned off, and the sample cooled naturally to near room temperature. An infrared thermal imaging camera recorded the sample temperature at 15-second intervals, acquiring data for 5 minutes during the heating phase and 10 minutes during the cooling phase.

[0082] Based on the obtained temperature-time curve and combined with formulas (1) to (4), the photothermal conversion efficiency of AuNR@Ir / IrO2-PEG nanozyme was calculated to evaluate its photothermal performance. Figure 3 ).

[0083] in: T 环境温度 =20℃;

[0084] θ As an auxiliary variable;

[0085] t Time (s);

[0086] hA The overall thermal conductivity of the system (W·K) -1 );

[0087] A λ : The absorbance of the sample at the laser wavelength λ;

[0088] τ: Time constant (s);

[0089] η :efficiency;

[0090] The calculation process is as follows:

[0091] Based on the sample temperature data recorded at each time point during the cooling process, substitute it into formula (1) to calculate the corresponding temperature at each time point. θ Value. With time as the x-axis, lnθ Plot a scatter plot of Time–lnθ with the ordinate as the ordinate, and perform a linear fit on the data. The fitting results show that the curve can be represented by a linear function, and its slope corresponds to the system's time constant. τ Calculated τ =168.33s ( Figure 3 ).

[0092] In calculating the photothermal conversion efficiency, the heat contribution of the sample container must also be considered. Since the temperature of the centrifuge tube also increases with the sample temperature during laser irradiation, this heat cannot be ignored. The centrifuge tube used in the experiment has a mass of 0.15g and a specific heat capacity of 2.0J / (g·℃). Therefore, the total heat of the system is corrected according to formula (5), and the calculation process is as follows:

[0093] ;

[0094] The formula for calculating solvent absorption power is:

[0095] ;

[0096] The absorbance of 100 μg / ml AuNR@Ir / IrO2-PEG nanozyme was A=2.1725 at a wavelength of 1064 nm. Substituting the above result into equation (3).

[0097] ;

[0098] Calculations using the formula show that the photothermal conversion efficiency of AuNR@Ir / IrO2-PEG nanozymes is 46.3%. This result indicates that the material possesses excellent photothermal energy conversion capabilities under near-infrared (NIR) light irradiation. AuNR@Ir / IrO2-PEG nanozymes can rapidly achieve localized temperature increases under low-power NIR laser irradiation. This performance provides significant advantages for its application in biomedical fields such as photothermal therapy (PTT) and photoacoustic imaging (PAI), demonstrating good thermal stability and therapeutic potential.

[0099] Experimental Example 3: Detection of catalase activity (CAT) of AuNR@Ir / IrO2-PEG / Ce6 nanozyme (UV-Vis 240 nm direct method).

[0100] The catalase activity of AuNR@Ir / IrO2-PEG / Ce6 nanozyme was determined by UV-Vis spectrophotometry at 25 °C. First, without the addition of nanozyme, the absorbance of H2O2 solutions of different concentrations was measured at 240 nm to establish the correlation between H2O2 concentration and absorbance.

[0101] Subsequently, the AuNR@Ir / IrO2-PEG / Ce6 nanozyme was added to a buffer solution to achieve a mass concentration of 1.5 μg / mL in the reaction system. H2O2 was used as the substrate, and the substrate concentration was adjusted to 0.5, 1, 2, 3, 4, 5, and 6 mM by varying the amount of H2O2 added. After the reaction started, the absorbance at 240 nm was measured at the beginning of the reaction and 1 min after the reaction had proceeded, after adjusting for the background absorption of the nanozyme and the effects of spontaneous decomposition of H2O2.

[0102] Based on the change in absorbance and the established H2O2 standard relationship, the reaction rate under different substrate concentrations was calculated. Kinetic fitting was performed using the Michaelis-Menten equation and the Lineweaver–Burk double reciprocal equation to obtain the Michaelis constant Km and the maximum reaction rate Vmax of the nanozyme. Figure 4 ).

[0103] The concentration of AuNR@Ir / IrO2-PEG / Ce6 nanozyme is [E] = 3.14 × 10⁻⁶. -12 M, from which the catalytic constant (kcat) and catalytic efficiency (Kcat / Km) can be calculated.

[0104] Kcat = Vmax / [E] = 7.23 × 10 6 s -1 ;

[0105] Kcat / Km = 4.2 × 10 5 mM -1 s -1 ;

[0106] The test results show that the AuNR@Ir / IrO2-PEG / Ce6 nanozyme prepared in this invention exhibits excellent catalase-like (CAT) catalytic activity in the H2O2 decomposition reaction. Its effective concentration [E] = 3.08 × 10⁻⁶ -12 The catalytic constant kcat calculated under M conditions is as high as 7.23 × 10⁻⁶. 6 s -1 This is significantly higher than the kcat values ​​of previously reported CAT-type nanozyme systems such as Pt NPs-PVP, Ft-Pt NPs, and Ir NPs-PVP (which are typically only 10). 2 -10 2s -2 The range is shown in Table 1. The results show that, compared with other noble metal and metal oxide nanozymes, the material of this invention exhibits higher substrate affinity (low Km), faster oxygen production rate (high Vmax), and a catalytic turnover frequency that is orders of magnitude higher (high kcat), and its overall catalytic performance is at the excellent level of the current CAT nanozyme system.

[0107] Table 1. KCAT values ​​for different types of catalysts

[0108]

[0109] Note: AuNR@Ir / IrO2-PEG / Ce6 is the nanozyme prepared in Example 1 of this application; Fe-SANzyme is referred to Edge‐Site Engineering of Defective Fe–N4 Nanozymes with Boosted Catalase‐Like Performance for Retinal Vasculopathies[J]. Advanced Materials, 2022, 34(39): 2205324; CuSACO is referred to Bioorthogonal Cu Single‐Atom Nanozyme for Synergistic Nanocatalytic Therapy, Photothermal Therapy, Cuproptosis and Immunotherapy[J]. Angewandte Chemie International Edition, 2024, 63(27): e202405937; PtNPs-PVP is referred to Ultrasmall platinum nanozymes as broad-spectrum antioxidants for theranostic application in acute kidney injury[J]. Chemical Engineering Journal, 2021, 409: 127371; Ft-Pt NPs is referred to Direct evidence for catalase and peroxidase activities of ferritin–platinum nanoparticles[J]. Biomaterials, 2011, 32(6): 1611-1618; AC-G9 / Pt NPs is referred to Generation 9 Polyamidoamine Dendrimer Encapsulated Platinum Nanoparticle Mimics Catalase Size, Shape, and Catalytic Activity[J].Langmuir, 2013, 29(17): 5262-5270; for PBNPs, see Prussian BlueNanoparticles as Multienzyme Mimetics and Reactive Oxygen Species Scavengers[J]. Journal of the American Chemical Society, 2016, 138(18): 5860-5865; for IrNPs-PVP, see Multi-enzyme mimetic ultrasmall iridium nanozymes as reactiveoxygen / nitrogen species scavengers for acute kidney injury management[J]. Biomaterials, 2021, 271: 120706.

[0110] The high CAT activity of the nanozyme in this invention mainly originates from the strong interfacial electronic coupling effect between the AuNR gold nanorods and the Ir / IrO2 shell, as well as the Ir 0 / Ir 4+ The continuous redox cycle channel constructed by the synergistic construction of multivalent iridium makes electron transfer during the H2O2 decomposition process more efficient; sub-nanometer iridium clusters provide abundant exposed active sites, and PEG modification ensures stable dispersion of particles in the aqueous system, thereby maintaining high catalytic efficiency. With its superior oxygen production capacity, the material of this invention can efficiently consume excess H2O2 and continuously release O2 in the tumor microenvironment, effectively alleviating tumor hypoxia and significantly enhancing the photodynamic therapy (PDT) effect of photosensitizers. This provides key technical support for realizing integrated multimodal tumor diagnosis and treatment based on "oxygen self-supply - photothermal synergy - photodynamic enhancement".

[0111] Experimental Example 4: Detection of peroxidase activity (POD) of AuNR@Ir / IrO2-PEG / Ce6 nanozyme.

[0112] AuNR@Ir / IrO2-PEG / Ce6 nanozyme dispersion (2 μg / mL, using deionized water as solvent) was used to determine peroxidase (POD) activity at room temperature. 3% H2O2 solution was used as the substrate, and 3,3',5,5'-tetramethylbenzidine (TMB) was used as the colorimetric reagent.

[0113] The specific steps are as follows: Different concentrations of H2O2 were added to the above nanozyme dispersion to achieve final H2O2 concentrations of 0.2, 0.5, 1, 2, 4, 10, 40, 100, 200, 400, and 800 mM, respectively. Simultaneously, TMB solution was added to achieve a final concentration of 0.2 mM. After thorough mixing, the mixture was reacted at room temperature. The absorbance (A) of the reaction system at 652 nm was measured using a UV-Vis spectrophotometer after 60 seconds of reaction. 652 ( ), to characterize the degree to which TMB is oxidized during the reaction.

[0114] Subsequently, based on the absorbance data measured at different substrate concentrations, the corresponding reaction rates were calculated, and Michaelis-Menten equation curves (V–[S] curves) and Lineweaver–Burk double reciprocal curves (1 / V–1 / [S] curves) were plotted. The Michaelis constant (Km) and maximum reaction rate (Vmax) were calculated using a nonlinear fitting method to evaluate the catalytic activity of AuNR@Ir / IrO2-PEG / Ce6 nanozyme for H2O2 and its substrate affinity. Figure 5 ).

[0115] Furthermore, using the same experimental conditions—fixing the H2O2 concentration while varying the TMB concentration—the affinity of the nanozyme for the TMB substrate and its catalytic kinetic parameters were further determined. The combined results of the two sets of experiments comprehensively reflect the peroxidase catalytic performance and reaction characteristics of this nanozyme. Figure 6 ).

[0116] The results showed that when the TMB concentration was fixed and the H2O2 concentration was changed, the Michaelis constant (Km) of the reaction was 44.46 mM and the maximum reaction rate (Vmax) was 31.77 μM / s; when the H2O2 concentration was fixed and the TMB concentration was changed, Km was 0.039 mM and Vmax was 13.34 μM / s.

[0117] The concentration of the nanozyme is [E] = 4.19 × 10⁻⁶. -12 M, from which the catalytic constant (kcat) and catalytic efficiency (Kcat / Km) can be calculated:

[0118] When the TMB concentration is fixed and the H2O2 concentration is changed:

[0119] Kcat = Vmax / [E] = 7.58 × 10 6 s -1 ;

[0120] Kcat / Km = 1.7 × 10 5 mM -1 s -1 ;

[0121] When the H2O2 concentration is fixed and the TMB concentration is changed:

[0122] Kcat = Vmax / [E] = 3.18 × 10 6 s -1 ;

[0123] Kcat / Km = 8.15 × 10 7 mM -1 s -1 ;

[0124] As shown in Table 2, the experimental results demonstrate that the AuNR@Ir / IrO2-PEG / Ce6 nanozyme of this invention exhibits excellent peroxidase-like (POD) activity in the TMB / H2O2 chromogenic system. When TMB is used as the substrate, its Km is only 0.039 mM, far lower than common nanozymes (such as Fe3O4, Co3O4, Pt NPs, and Ir nanoparticles), showing extremely high substrate affinity; its maximum reaction rate Vmax reaches 13.34 μM / s, corresponding to a catalytic constant kcat as high as 3.18 × 10⁻⁶. 6 s -1 It significantly outperforms natural horseradish peroxidase (HRP) and most reported metal oxide, iron-based magnetic nanozymes, and noble metal nanozyme systems. Its catalytic efficiency reaches 8.15 × 10⁻⁶ kcat / Km. 7 mM -1 ·s -1 The diffusion limit has been reached, indicating that the nanozyme has achieved extremely high levels in substrate binding, electron transfer, and oxidation reaction rate, making it one of the best performing materials among similar nanozyme systems.

[0125] Table 2. KCAT values ​​for different types of catalysts

[0126]

[0127] Note: AuNR@Ir / IrO2-PEG / Ce6 is the nanozyme prepared in Example 1 of this application; for HRP, see Intrinsic peroxidase-like activity of ferromagnetic nanoparticles[J]. Nature Nanotechnology, 2007, 2(9): 577-583; for Co3O4, see Co3O4 Nanoparticles with Multi-Enzyme Activities and Their Application in Immunohistochemical Assay[J]. ACS Applied Materials&Interfaces, 2014, 6(3): 1959-1970; for Fe3O4, see Co3O4 Nanoparticles with Multi-Enzyme Activities and Their Application in Immunohistochemical Assay[J]. ACS Applied Materials&Interfaces, 2014, 6(3): 1959-1970; for Ft-Pt NPs, see Direct evidence for catalase and peroxidase activities of ferritin–platinum nanoparticles[J]. Biomaterials, 2011, 32(6): 1611-1618; for Pt NPs-PVP, see Ultrasmall platinum nanozymes as broad-spectrum antioxidants for theranostic application in acute kidney injury[J]. Chemical Engineering Journal, 2021, 409: 127371; for Ptc-PA, see Atomic-scale strain engineering of atomically resolved Pt clusters transcending natural enzymes[J].NatureCommunications, 2024, 15(1): 8346; F-Cu bionanozyme, see Engineering a SingleAmino Acid Bionanozyme for Ultrasensitive Detection of Biomarkers: A WHO-REASURE- Aligned Approach[J]. Advanced Functional Materials, 2025: 2502902; IrNPs, see Intrinsic Peroxidase-Mimicking Ir Nanoplates for NanozymaticAnticancer and Antibacterial Treatment[J]. ACS Appl. Mater. Interfaces, 2020; Ir NPs-PVP see Multi-enzyme mimetic ultrasmall iridium nanozymes as reactiveoxygen / nitrogen species scavengers for acute kidney injury management[J]. Biomaterials, 2021, 271: 120706.

[0128] The aforementioned performance advantages mainly stem from the unique AuNR core / Ir-IrO2 core-shell structure of the material of this invention and the high proportion of surface-active atoms brought about by sub-nanometer-scale iridium clusters; among which Ir 0 / Ir 4+ The coexistence of multiple valence states constructs a continuous electron transport channel, accelerating the redox cycle, while the interfacial coupling between Au and Ir / IrO2 further enhances electron migration efficiency. PEG modification ensures high accessibility of the catalytic site and colloidal stability, avoiding activity decay caused by aggregation. Therefore, the POD activity of the nanozyme of this invention is not only significantly superior to that of traditional nanozyme systems, but also synergistic with its CAT oxygen production function and photothermal / photodynamic properties. It can exert a more efficient role in ROS generation and oxidative stress enhancement in tumor microenvironment regulation and multimodal therapy, and has broad prospects for biomedical applications.

[0129] Experimental Example 5: Detection of oxidase activity (OXD) of AuNR@Ir / IrO2-PEG / Ce6 nanozyme.

[0130] To verify the oxidase (OXD) activity of the prepared AuNR@Ir / IrO2-PEG / Ce6 nanozyme, catalytic experiments were conducted using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic substrate under conditions without added H2O2.

[0131] The specific steps are as follows: Take 0.5 mM TMB solution and AuNR@Ir / IrO2-PEG / Ce6 nanozyme dispersion with a mass concentration of 2 μg / mL, and mix them evenly in a 3 mL cuvette. Immediately after mixing, use a UV-Vis spectrophotometer to continuously record the absorbance change of the reaction system at 652 nm for 12 minutes.

[0132] To further verify the role of oxygen in the catalytic reaction, a control group was set up: TMB solution and AuNR@Ir / IrO2-PEG / Ce6 nanozyme of the same concentration were added to deionized water that had been bubbled with nitrogen for 15 minutes to remove dissolved oxygen. After mixing, the absorbance at 652 nm was recorded over time under the same conditions.

[0133] By comparing the kinetic curves of the two sets of experiments, it can be clearly observed that the rate of increase in absorbance of the reaction system under normal air conditions is significantly higher than that of the control group under nitrogen conditions. Figure 7 This indicates that oxygen participated in the oxidation reaction of TMB in this system, further demonstrating that the AuNR@Ir / IrO2-PEG / Ce6 nanozyme has excellent oxidase (OXD) catalytic activity and can directly oxidize the substrate using dissolved oxygen.

[0134] Experimental Example 6: Photoacoustic imaging capability of AuNR@Ir / IrO2-PEG / Ce6 nanozyme in vivo.

[0135] To verify the photoacoustic imaging performance of the AuNR@Ir / IrO2-PEG / Ce6 nanozyme described in this invention in vivo, 8-week-old healthy BALB / c nude mice were selected as experimental animal models. First, the abdominal skin of the mice was cut open, and 30 μL of a suspension containing Hepa1-6 mouse hepatocellular carcinoma cells was injected into the liver to establish an in situ hepatocellular carcinoma model. After injection, the incision was sutured, and the mice were fed as usual for 10 days to allow the tumor to fully grow and mature within the liver.

[0136] Subsequently, 100 μL of an appropriately concentrated AuNR@Ir / IrO2-PEG / Ce6 nanozyme dispersion was injected via the tail vein. Twelve hours after intravenous injection, the nanozyme actively accumulated in the tumor tissue due to the enhanced permeation and retention effect (EPR effect) at the tumor site.

[0137] In the imaging experiment, mice were anesthetized and fixed on the photoacoustic imaging system platform. A pulsed laser with a wavelength of 1064 nm was used to irradiate the abdominal tumor area of ​​the mice, while a photoacoustic detector simultaneously acquired photoacoustic signals from a cross-section of the liver. The acquired data, after system reconstruction and processing, showed that the tumor area produced significantly enhanced photoacoustic signals, forming a clear contrast with the surrounding normal tissue, and allowing for a direct depiction of the tumor's contour structure (e.g., ...). Figure 8 (As shown).

[0138] The experimental results demonstrate that the AuNR@Ir / IrO2-PEG / Ce6 nanozyme described in this invention possesses excellent near-infrared absorption capacity and high photoacoustic conversion efficiency, enabling high-contrast photoacoustic imaging under physiological conditions. This performance not only facilitates early tumor identification and precise localization but also provides real-time imaging guidance and integrated diagnostic and therapeutic support for the synergistic implementation of subsequent photothermal therapy (PTT) and photodynamic therapy (PDT).

[0139] Example 7: Evaluation of the in vivo tumor therapeutic effect of AuNR@Ir / IrO2-PEG / Ce6 nanozyme.

[0140] To verify the in vivo tumor therapeutic performance of the AuNR@Ir / IrO2-PEG / Ce6 nanozyme described in this invention, an in vivo experiment was conducted using a mouse model loaded with subcutaneous tumors. Eight-week-old BALB / c-nu nude mice were used as experimental animals, and Hepa1-6 mouse liver cancer cells were subcutaneously inoculated into them. The tumors were allowed to grow to approximately 100 mm. 3 Mice were then randomly divided into 6 groups, with 4 mice in each group, and were treated as follows:

[0141] Control group (PBS): An equal volume of PBS solution was injected via the tail vein, and no light treatment was applied.

[0142] Light-controlled group (PBS + laser): PBS was injected via tail vein and then laser irradiation was performed.

[0143] Drug group (AuNR@Ir / IrO2-PEG / Ce6): only nanozyme was injected, without light exposure;

[0144] PDT group (AuNR@Ir / IrO2-PEG / Ce6+660nm laser): After injection of nanozyme, the tumor site was irradiated with a 660nm laser, and photodynamic therapy was performed under constant temperature conditions.

[0145] PTT group (AuNR@Ir / IrO2-PEG / Ce6+1064nm laser): After injection of nanozyme, the tumor site was irradiated with a 1064nm laser for photothermal therapy;

[0146] Combined treatment group (AuNR@Ir / IrO2-PEG / Ce6+660nm+1064nm laser): After injection of nanozyme, 660nm light irradiation and 1064nm light irradiation were performed successively to achieve combined photodynamic and photothermal therapy.

[0147] During the experiment, each group of mice was injected with nanozyme dispersion (approximately 100 μL) via the tail vein, and then subjected to corresponding laser irradiation treatment 12 hours later. The laser power density and irradiation time were controlled within the same range for each group to ensure consistent experimental conditions.

[0148] During the subsequent 18-day observation period, tumor volume and body weight changes in mice were measured and recorded daily. Results showed that tumor volume continued to increase in the PBS group, PBS+laser group, and the group receiving only AuNR@Ir / IrO2-PEG / Ce6 injection, indicating no significant therapeutic effect. Mice receiving only PDT (660nm light irradiation) experienced a significantly slower tumor growth rate, but still showed a certain upward trend. In contrast, tumor volume in the PTT (1064nm light irradiation) group and the combined treatment (PDT+PTT) group gradually shrank after treatment, almost completely regressing after approximately 6 days, with no obvious signs of recurrence. Figure 9 ).

[0149] The experimental results fully demonstrate that the AuNR@Ir / IrO2-PEG / Ce6 nanozyme described in this invention can simultaneously exert excellent photothermal therapy (PTT) and photodynamic therapy (PDT) effects under light irradiation. Its synergistic effect significantly enhances tumor inhibition and clearance efficiency, exhibiting good in vivo biocompatibility and high-efficiency comprehensive therapeutic potential, providing a new technical approach for integrated tumor diagnosis and treatment.

[0150] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A mesoporous core-shell structured nanozyme with multi-enzyme activity, characterized in that, The nanozyme has a core-shell structure, with gold nanorods as the core and an outer shell composed of iridium and its oxides. The outer shell has a mesoporous structure and loads the photosensitizer dihydroporphyrin E6 through this mesoporous structure. The preparation method of the mesoporous core-shell structured nanozyme with multi-enzyme activity is as follows: Preparation steps of gold nanorods: Gold nanorods are prepared by seed-mediated method; gold nanorods are dispersed in dispersion medium to obtain gold nanorod dispersion; The coating steps for gold nanorods are as follows: a hexadecyltrimethylammonium chloride solution is added to a gold nanorod dispersion to obtain a mixed solution; an iridium trichloride solution is added to the mixed solution and a hydrothermal reaction is carried out to obtain a core-shell structure of gold nanorods@iridium nanoclusters; the core-shell structure of gold nanorods@iridium nanoclusters is purified and the template is removed to obtain gold nanorod nanozymes coated with iridium nanoclusters. Polyethylene glycol modification steps: Iridium nanoclusters coated with gold nanorod nanozymes are added to amino polyethylene glycol solution to obtain a polyethylene glycol modification reaction system; the polyethylene glycol modification reaction system is reacted, and the precipitate is collected after the reaction is completed to obtain polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozymes. Photosensitizer loading steps: Polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozymes were dispersed in water to obtain a polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozyme solution; dihydroporphyrin E6 was added to the polyethylene glycol-modified iridium nanoclusters coated with gold nanorod nanozyme solution to obtain a photosensitizer loading system; the photosensitizer loading system was reacted under light-protected conditions, and the precipitate was collected after the reaction to obtain a mesoporous core-shell structured nanozyme with multi-enzyme activity; The step of preparing gold nanorods via a seed-mediated method includes: preparing a seed solution using chloroauric acid solution as a precursor under the action of a strong reducing agent and a surfactant; growing gold nanorods in the seed solution under the action of a surfactant, a morphology modifier, a weak reducing agent, and chloroauric acid solution to obtain a crude gold nanorod solution; wherein the strong reducing agent includes sodium borohydride solution; the surfactant includes hexadecyltrimethylammonium bromide solution; the morphology modifier includes silver nitrate solution; and the weak reducing agent includes 3-aminophenol solution. In the preparation steps of gold nanorods, dispersing gold nanorods in a dispersion medium includes: centrifuging a crude gold nanorod solution to collect the precipitate, washing the precipitate with water, and then dispersing the precipitate in a dispersion medium to obtain a gold nanorod dispersion; the dispersion medium includes deionized water.

2. The mesoporous core-shell structured nanozyme according to claim 1, characterized in that, In the gold nanorod coating step, the mass ratio of gold nanorods to hexadecyltrimethylammonium chloride in the mixed solution is 1:50-1:100; the final concentration of hexadecyltrimethylammonium chloride in the mixed solution is 0.04-0.08M.

3. The mesoporous core-shell structured nanozyme according to claim 1, characterized in that, In the gold nanorod coating step, the volume ratio of the iridium trichloride solution to the mixed solution is 1:25; the concentration of the iridium trichloride solution is 0.05M.

4. The mesoporous core-shell structured nanozyme according to claim 1, characterized in that, In the coating step of gold nanorods, the hydrothermal reaction after adding iridium trichloride solution to the mixed solution includes: after adding iridium trichloride solution to the mixed solution, stirring is first used to make iridium ions uniformly adsorbed on the surface of gold nanorods, and then the temperature is raised to 230℃-250℃ and the reaction is carried out for 1-3 hours to promote further crystallization and uniform coating of iridium nanoclusters.

5. The mesoporous core-shell nanozyme according to claim 1, characterized in that, In the step of coating gold nanorods with iridium nanoclusters, the purification and template removal are carried out by washing the core-shell structure of gold nanorods@iridium nanoclusters in ethanol to remove unreacted substances and residual surfactants on the surface of the core-shell structure of gold nanorods@iridium nanoclusters, and obtaining a washed precipitate. The washed precipitate was then dispersed in an ammonium nitrate ethanol solution and refluxed to remove residual surfactants inside the pores of the gold nanorods@iridium nanoclusters. In the step of coating gold nanorods with iridium nanoclusters, the concentration of the ammonium nitrate ethanol solution was 2 g / L. The reflux heating temperature was 80℃ and the time was 24 h.

6. The mesoporous core-shell nanozyme according to claim 1, characterized in that, In the polyethylene glycol modification step, the mass ratio of iridium nanoclusters-coated gold nanorod nanozymes to amino polyethylene glycol in the polyethylene glycol modification reaction system is 1:25-1:50, and the mass concentration of amino polyethylene glycol is 2.5 mg / mL.

7. The mesoporous core-shell nanozyme according to claim 1, characterized in that, In the Ce6 loading step, the mass ratio of polyethylene glycol-modified iridium nanoclusters-coated gold nanorod nanozymes to photosensitizer dihydroporphyrin E6 in the photosensitizer loading system is 1:2-1:5; the amount of photosensitizer dihydroporphyrin E6 added to the polyethylene glycol-modified iridium nanoclusters-coated gold nanorod nanozyme solution is 5 mg.

8. The use of the mesoporous core-shell nanozyme with multi-enzyme activity as described in any one of claims 1-7 in the preparation of photosensitizers that induce tumor death.

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