Modified ldh composites and their use in bone regeneration and treatment of bone tumors

Abstract

The present application relates to the technical field of biomedical materials, and particularly relates to a modified LDH composite material and application thereof in bone regeneration and treatment of bone tumors. The modified LDH composite material is prepared by the following steps: firstly, zinc-calcium-molybdenum hydrotalcite nanosheets are synthesized by a coprecipitation method; then the hydrotalcite nanosheets are subjected to alkali etching; yeast is loaded on the etched zinc-calcium-molybdenum nanosheets to induce intracellular mineralization of hydroxyapatite nanoparticles and promote bone regeneration; meanwhile, the strength of collagen fiber gel is enhanced in situ, and the bone mineralization process is simulated; the yeast can destroy the glycolysis of tumor cells, consume glucose and lactic acid, and combine with efficient SDT to induce ICD, destroy the immunosuppressive microenvironment in the tumor area, and activate T cells; and the yeast has excellent anti-tumor and bone repair performance.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to modified LDH composite materials and their application in bone regeneration and treatment of bone tumors. Background Technology

[0002] Treatment of bone tumors (including primary osteosarcoma and metastatic bone tumors) typically involves a combination of surgical resection, radiotherapy, and chemotherapy. However, extensive tumor resection often results in large bone defects, while radiotherapy and chemotherapy may further inhibit bone repair, leading to complications such as delayed healing or nonunion. Bone regeneration is a complex physiological process in which the human skeletal system repairs its structure and function after injury or disease, involving the precise coordination of cells, growth factors, scaffold materials, and the biomechanical microenvironment. With the increasing aging of the global population and the high incidence of diseases such as trauma, bone tumors, and osteoporosis, the demand for bone defect repair has increased significantly. Traditional treatment methods (such as autologous / allogeneic bone transplantation) face challenges such as limited donors, immune rejection, and the need for secondary surgery, prompting tissue engineering and regenerative medicine to become key directions for overcoming these bottlenecks. Therefore, how to effectively treat tumors while promoting bone tissue regeneration has become an important challenge in both clinical and basic research.

[0003] In recent years, with the development of tissue engineering and regenerative medicine, synergistic strategies for bone tumor treatment and bone regeneration have received widespread attention. On the one hand, novel anti-tumor technologies (such as targeted drug delivery systems and photothermal / immunotherapy) can precisely kill tumor cells and reduce damage to surrounding healthy tissues; traditional bone regeneration paradigms usually rely on metal or synthetic scaffolds, but these limit sufficient vascularization and the potential for new bone growth within non-biodegradable structures. Strategies that mimic the regeneration of mature bone through high-dose stem cells or local delivery of growth factors have limited in vivo cell survival, insufficient vascular supply, and unavoidable ectopic bone formation. Therefore, there is an urgent need to develop combined bone regeneration strategies that can maintain long-term activity and utilize absorbable biomaterials, potent stem cells, and physiologically soluble factors. In particular, smart materials with dual "treatment-regeneration" properties (such as drug-loaded bone cement and responsive hydrogels) can both locally release chemotherapy drugs to inhibit tumor recurrence and provide a supportive microenvironment for bone regeneration.

[0004] Layered double hydroxides (LDHs) are a class of two-dimensional nanomaterials with a unique layered structure, and their general chemical formula is [M]. 2+ 1-x M 3+ x (OH)2] x+ [A n- ] x / n•mH2O possesses a tunable metal ion composition, interlayer anion exchange capacity, and good biocompatibility. In recent years, LDH has shown broad application potential in the biomedical field, especially in the synergistic strategy of bone tumor treatment and bone tissue regeneration, which has attracted widespread attention.

[0005] In the treatment of bone tumors, LDH, due to its high specific surface area and positive surface charge, can serve as a highly efficient drug carrier for loading chemotherapeutic drugs (such as doxorubicin and cisplatin), nucleic acids (such as siRNA), or photothermal / photodynamic therapeutic agents, achieving controlled release in response to the tumor microenvironment. Simultaneously, LDH itself can be released via metal ions (such as Mg²⁺). 2+ Zn 2+ The release of LDH regulates tumor cell metabolism or induces intracellular pH imbalance through laminolysis, thereby enhancing anti-tumor effects. Furthermore, LDH can also act as an immunomodulator, inhibiting tumor recurrence and metastasis by activating macrophage polarization or delivering immune checkpoint inhibitors.

[0006] In bone tissue regeneration, the biomimetic mineral composition of LDH (such as MgAl-LDH and ZnFe-LDH) can mimic the inorganic components of the natural bone matrix, promoting osteoblast adhesion, proliferation, and differentiation. Its interlayer can intercalate bone-inducing anions (such as phosphate and vitamin C) or complex with growth factors (such as BMP-2), further accelerating bone repair. LDH nanosheets can also enhance the osteogenic differentiation capacity of mesenchymal stem cells by regulating signaling pathways such as Wnt / β-catenin and BMP / Smad. Furthermore, porous scaffolds constructed from LDH and polymers (such as chitosan and polylactic acid) provide both mechanical support and time-dependent release of drugs / growth factors, meeting the dual needs of "anti-tumor and regeneration promotion."

[0007] Yeast cells, due to their cell walls being rich in phosphorylated polysaccharides (such as mannan) and negatively charged groups (such as carboxyl and phosphate groups), can effectively adsorb calcium. 2+ Furthermore, it serves as a nucleation site to induce HAP deposition. Studies have shown that yeast can not only promote mineralization extracellularly by altering local pH and ion concentration through metabolic activities, but also take up calcium and phosphate precursors intracellularly via endocytosis, forming nanoscale HAP particles in organelles (such as vacuoles). This intracellular mineralization process highly mimics the microscopic mechanism of bone formation in vivo. The prepared HAP nanoparticles exhibit characteristics such as uniform size, good dispersibility, and surface biomolecular modification, demonstrating unique advantages in drug delivery, bone repair, and tumor therapy. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by proposing a modified LDH composite material and its application in bone regeneration and treatment of bone tumors. The prepared LDH composite material is required to have excellent integrated bone tumor treatment and regeneration properties.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] The preparation method of modified LDH composite material includes the following steps:

[0011] Zinc salt, calcium salt, molybdenum salt, sodium hydroxide and water were mixed under a nitrogen atmosphere to reach the desired pH. The resulting mixed solution was then subjected to hydrothermal coprecipitation to obtain zinc-calcium-molybdenum hydrotalcite micro flakes.

[0012] Zinc-calcium-molybdenum hydrotalcite microplates were etched with sodium hydroxide to obtain etched zinc-calcium-molybdenum hydrotalcite material.

[0013] Single colonies were picked from the preserved plates, inoculated into liquid culture medium, and cultured with shaking to obtain yeast.

[0014] Yeast was added to the above solution and stirred to obtain the Yeast@DR-ZnCaMo-LDH composite material.

[0015] Preferably, the molar ratio of the zinc salt, calcium salt, and molybdenum salt is 80:20:20:714.

[0016] Preferably, the concentration of the sodium hydroxide solution is 40 mg / mL.

[0017] Preferably, the hydrothermal coprecipitation temperature is 80°C and the reaction time is 24 hours.

[0018] Preferably, the sodium hydroxide concentration used for etching is 0.3M.

[0019] Preferably, the etching temperature is 120°C and the etching time is 3 hours.

[0020] Preferably, the zinc-calcium-molybdenum hydrotalcite microsheets are hexagonal nanosheets with a size of 50-110 nm and a thickness of 17-18 nm.

[0021] Preferably, the etched zinc-calcium-molybdenum hydrotalcite material has a uniform sheet-like structure with a size of 40-100 nm.

[0022] Preferably, the yeast culture medium is YPD liquid culture medium.

[0023] Preferably, the yeast is shaken at 30°C, 200 rpm, for 12-16 hours (until OD). 600 ≈2.0).

[0024] Preferably, the yeast has an OD value of 2.0 and a volume of 0.5 ml, and the etched zinc-calcium-molybdenum hydrotalcite microplates have a concentration of 200 μg / ml and a volume of 1 ml.

[0025] Preferably, the yeast is stirred with the etched hydrotalcite micro-sheets for 6 hours.

[0026] The present invention provides a modified LDH composite material prepared by the aforementioned preparation method, comprising etched zinc-calcium-molybdenum hydrotalcite material and yeast.

[0027] The present invention also provides the application of the aforementioned modified LDH composite material in bone regeneration and treatment of bone tumors.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. This invention first synthesizes zinc-calcium-molybdenum hydrotalcite nanosheets using a co-precipitation method, then etches the hydrotalcite nanosheets with alkali, and loads yeast cells onto the etched zinc-calcium-molybdenum nanosheets. Under the condition of yeast cells loaded with LDH, calcium is released along with the LDH. 2+ And Ca exists 2+ and PO4 3- It induces intracellular mineralization of hydroxyapatite nanoparticles (nHAP), promoting bone regeneration. Simultaneously, it enhances the gel strength of collagen fibers in situ, biomimetically mimicking the bone mineralization process.

[0030] 2. The yeast used in this invention can disrupt tumor cell glycolysis, consume glucose and lactic acid, and, combined with highly efficient SDT to induce ICD, disrupt the immunosuppressive microenvironment in the tumor region and activate T cell activity.

[0031] 3. The zinc-calcium-molybdenum nanosheets synthesized in this invention generate a large amount of ROS under the action of ultrasound, which induces excellent ICD therapeutic effects and can effectively inhibit bone tumors.

[0032] 4. The zinc-calcium-molybdenum hydrotalcite-based nanocomposite material prepared by this invention uses readily degradable raw materials, has good biocompatibility, and is simple and easy to operate. It combines anti-bone tumor and bone regeneration functions and has broad prospects in related surgeries. Attached Figure Description

[0033] Figure 1 Atomic force microscopy (AFM) characterization image of the ZnCaMo-LDH nanosheets prepared in Example 1 of this invention;

[0034] Figure 2 The images show high-resolution transmission electron microscopy (HRTEM) characterizations of ZnCaMo-LDH and DR-ZnCaMo-LDH prepared in Example 1 of this invention, where (a) is the lattice fringe pattern of the original ZnCaMo-LDH nanosheets and (b) is the amorphous structure of the DR-ZnCaMo-LDH nanosheets after defect modulation.

[0035] Figure 3ZnCaMo-LDH, DR-ZnCaMo-LDH, and TiO2 prepared in Example 1 of this invention generate singlet oxygen under ultrasonic conditions. 1 Comparison of SOSG fluorescence detection results for O2;

[0036] Figure 4 ZnCaMo-LDH, DR-ZnCaMo-LDH, and TiO2 prepared in Example 1 of this invention generate singlet oxygen under ultrasonic conditions. 1 Comparison of electron paramagnetic resonance (EPR) spectra of O2;

[0037] Figure 5 The UV-Vis absorption spectrum changes of ZnCaMo-LDH, DR-ZnCaMo-LDH and TiO2 prepared in Example 1 of the present invention on the degradation of DPBF under ultrasonic conditions;

[0038] Figure 6 ZnCaMo-LDH and DR-ZnCaMo-LDH prepared in Example 1 of this invention generate superoxide anions (O2) under ultrasonic conditions. - Comparison of DHR123 fluorescence detection results (·)

[0039] Figure 7 The ultraviolet-visible-near-infrared diffuse reflectance spectra and band gap calculation results of ZnCaMo-LDH and DR-ZnCaMo-LDH prepared in Example 1 of this invention;

[0040] Figure 8 The Mott-Schottky curves and calculated conduction band positions of ZnCaMo-LDH and DR-ZnCaMo-LDH prepared in Example 1 of this invention are shown below.

[0041] Figure 9 The zeta potential test results are shown for the DR-ZnCaMo-LDH nanosheets prepared in Example 1 of this invention, the yeast cells (Yeast) prepared in Example 2, and their complex (Yeast@DR-ZnCaMo-LDH). Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0043] Example 1

[0044] Preparation of Yeast@DR-ZnCaMo-LDH

[0045] Zn(NO3)2·6H2O (3.6 mmol), Ca(NO3)2·4H2O (0.4 mmol), and (NH4)6Mo7O 24 • 4H₂O (1 mmol) dissolved in deionized water (70 mL) as solution A. NaOH (40 mg / mL) -1 Solution B was added to solution A under a nitrogen atmosphere until the pH reached 9.7. The mixture was stirred vigorously at room temperature for 0.5 hours. The precipitate was collected and crystallized at 80°C for 24 hours in a PTFE-lined container. Finally, the synthesized ZnCaMo-LDH nanosheets were washed three times with deionized water and designated as ZnCaMo-LDH.

[0046] The prepared ZnCaMo-LDH nanosheets were dispersed in a 0.3 M NaOH solution, poured into a polytetrafluoroethylene-lined container, and incubated at 120 °C for 3 h. The precipitate was collected by centrifugation and then stored in cooled deionized water, denoted as DR-ZnCaMo-LDH.

[0047] Example 2

[0048] Cultured under constant temperature shaking conditions at 30°C and 200 rpm. Single colonies are picked from the plates and pre-cultured in 5 mL of liquid medium for 12-16 hours to allow the cells to enter the logarithmic growth phase (OD). 600 ≈1.0). Subsequently, the culture was transferred to fresh YPD medium at a ratio of 1:50 to 1:100 for expansion culture, and a high-density bacterial culture (OD) was obtained after 6-8 hours. 600 ≈2.0). After culturing, the bacterial cells were collected by centrifugation and washed with sterile buffer to remove residual culture medium components. The final bacterial cells could be used for subsequent binding with hydrotalcite and were designated Yeast.

[0049] Preparation of yeast and DR-ZnCaMo-LDH (Yeast@DR-ZnCaMo-LDH): The prepared DR-ZnCaMo-LDH nanosheets were dispersed in 1 ml of PBS solution (concentration 200 μg / ml). Then, at room temperature, the solution was magnetically stirred to add 0.5 ml of 10% DR-ZnCaMo-LDH. 8 Add 1 mL of ZnCaMo-LDH solution to a yeast PBS solution containing CFU / mL. After incubation for 6 hours, collect the resulting yeast-LDH complex by centrifugation at 6000 rpm for 5 minutes and store it in PBS solution at 4°C.

[0050] Characterization and testing

[0051] The ZnCaMo-LDH material prepared in Example 1 was systematically characterized by microstructure and analyzed by atomic force microscopy (AFM). Figure 1 The study revealed that the material exhibits a typical two-dimensional sheet-like morphology, with smooth surfaces and clear edges. The thickness measured was 17-18 nm, confirming its ultrathin structural characteristics. This structure is beneficial for increasing the specific surface area of ​​the material and providing abundant active sites. High-resolution transmission electron microscopy (HRTEM) characterization results (…) Figure 2 Further, the differences in the crystal structure of the materials were revealed: the original ZnCaMo-LDH nanosheets showed highly ordered lattice fringes, indicating that they have good crystallinity; while the defect-modified DR-ZnCaMo-LDH nanosheets showed amorphous structure characteristics, and the lattice fringes disappeared. This structural difference may significantly affect the electronic structure and surface properties of the materials, providing an important structural basis for subsequent performance optimization.

[0052] In order to systematically evaluate the singlet oxygen in materials ( 1 The O2 generation capacity was compared and analyzed using SOSG fluorescent probes and electron paramagnetic resonance (EPR) technology to compare the ZnCaMo-LDH prepared in Example 1, the defect-modified DR-ZnCaMo-LDH, and the control sample TiO2. Figure 3 and Figure 4 Experimental results showed that, under ultrasonic conditions, TiO2 and pristine ZnCaMo-LDH samples exhibited only negligible SOSG fluorescence signals, indicating that their... 1 The O2 generation capacity is relatively weak; however, DR-ZnCaMo-LDH nanosheets exhibit a significant fluorescence enhancement effect, and EPR testing also detected a significant fluorescence enhancement. 1 The O2 characteristic signal was clearly demonstrated. This result fully proves that the structural defects introduced by alkaline etching significantly enhance the performance of ZnCaMo-LDH nanosheets. 1 The O2 generation performance may be due to defect engineering optimizing the electronic structure of the material, which promotes the generation of reactive oxygen species.

[0053] To thoroughly evaluate the reactive oxygen species (ROS) generation capacity of the materials, we systematically studied the ZnCaMo-LDH prepared in Example 1, the defect-modified DR-ZnCaMo-LDH, and the control sample TiO2 using UV-Vis spectrophotometry. Figure 5As shown, monitoring the changes in the characteristic absorption peak of 1,3-diphenylisobenzofuran (DPBF) at 410 nm revealed that under ultrasonic conditions, TiO2 and the original ZnCaMo-LDH samples only caused weak DPBF degradation, with negligible changes in absorbance. In contrast, DR-ZnCaMo-LDH nanosheets exhibited significant DPBF degradation efficiency, with the absorbance at 410 nm decreasing rapidly over time, confirming their excellent ROS generation performance. This result corroborates the aforementioned SOSG and EPR test results, further validating the effectiveness of the alkaline etching modification strategy in enhancing the ROS generation capacity of ZnCaMo-LDH nanosheets, providing important experimental evidence for the development of highly efficient acoustic sensor materials.

[0054] To further evaluate the superoxide anion (O2) content of the material - •) To assess the generation capacity, we used the highly sensitive fluorescent probe dihydrorhodamine 123 (DHR123) to conduct a systematic comparative analysis of the ZnCaMo-LDH prepared in Example 1 and its defect-modified DR-ZnCaMo-LDH. Figure 6 Fluorescence spectroscopy results showed that under ultrasonic irradiation, the original ZnCaMo-LDH sample produced only a weak fluorescence signal, and its O2... - • The generation capacity is relatively limited; however, DR-ZnCaMo-LDH nanosheets modified by alkali etching exhibit a significant fluorescence enhancement effect, indicating that they possess excellent O2... - • Performance enhancement. This result is highly consistent with the aforementioned DPBF degradation experiments and SOSG / EPR test data, jointly confirming that defect engineering strategies can effectively modulate the electronic structure of ZnCaMo-LDH and significantly enhance its reactive oxygen species (including O2). - ·and 1 The generation efficiency of O2.

[0055] The band structure of the ZnCaMo-LDH and DR-ZnCaMo-LDH nanosheets prepared in Example 1 was systematically characterized by UV-Vis-NIR diffuse reflectance spectroscopy and Mott-Schottky analysis. Figure 7-8Test results show that the band gap (Eg) of the original ZnCaMo-LDH is 3.17 eV, while the band gap of the defect-tuned DR-ZnCaMo-LDH is significantly reduced to 2.30 eV. This narrow band gap characteristic makes it more easily excited by ultrasound (US). Further Mott-Schottky measurements show that the conduction band (CB) positions of ZnCaMo-LDH and DR-ZnCaMo-LDH are -0.57 eV and -0.16 eV, respectively, from which the calculated valence band (VB) positions are 2.60 eV and 2.14 eV, respectively. This change in band structure has significant implications: on the one hand, the reduced conduction and valence band positions of DR-ZnCaMo-LDH are more favorable for electron-hole (electron-hole) interactions. - -h + On the one hand, under ultrasonic excitation, electron-hole pairs in the valence band of DR-ZnCaMo-LDH are more easily separated than in the original sample, among which photogenerated electrons (e... - ) occupies the conduction band, while holes (h + These highly mobile photogenerated electrons remain in the valence band. They can effectively react with O2 molecules to generate superoxide anion radicals (O2). - ·), followed by O2 - • It further reacts with valence band holes to eventually generate singlet oxygen, which has strong oxidizing properties. 1 O2). This band structure regulation mechanism perfectly explains the significantly enhanced reactive oxygen species generation capacity of DR-ZnCaMo-LDH under ultrasonic conditions, providing an important theoretical basis for the design of highly efficient acoustic catalytic materials.

[0056] Zeta potentials of the DR-ZnCaMo-LDH nanosheets prepared in Example 1, the yeast cells prepared in Example 2, and their complex (Yeast@DR-ZnCaMo-LDH) were measured using dynamic light scattering (DLS) technology. Figure 9 The test results showed that DR-ZnCaMo-LDH nanosheets and yeast cells exhibited surface potentials of -5.56±0.34 mV and -14.17±0.45 mV, respectively, while the Zeta potential of the Yeast@DR-ZnCaMo-LDH complex was -9.46±0.34 mV. This significant change in potential value indicates that DR-ZnCaMo-LDH nanosheets have been successfully functionalized on the surface of yeast cells.

[0057] This study successfully developed a yeast@DR-ZnCaMo-LDH bioactive composite material with dual "therapeutic-regenerative" properties, providing an innovative solution for the integrated treatment of bone tumors and bone regeneration. By precisely controlling the alkaline etching process of ZnCaMo-LDH, DR-ZnCaMo-LDH nanosheets with amorphous structural features were obtained. The band gap was significantly reduced from 3.17 eV to 2.30 eV, and the conduction band position was increased from -0.57 eV to -0.16 eV. This optimized band structure greatly promoted the electron-hole pair separation efficiency under ultrasonic excitation, enabling the material to exhibit excellent reactive oxygen species (ROS) generation capabilities, including superoxide anions (O2). - ·) and singlet oxygen ( 1 O2), etc. Simultaneously, the surface functionalization modification of DR-ZnCaMo-LDH nanosheets was successfully achieved using the abundant negatively charged groups on the surface of yeast cells, and Zeta potential testing confirmed the successful construction of the composite material. This composite material innovatively combines the sonodynamic therapeutic advantages of DR-ZnCaMo-LDH with the biomineralization properties of yeast: on the one hand, it induces immunogenic death (ICD) of tumor cells by generating a large amount of ROS through ultrasound triggering, effectively inhibiting bone tumors; on the other hand, yeast can mediate the intracellular mineralization of hydroxyapatite (HAP), mimicking the natural bone formation process and promoting bone tissue regeneration. Material characterization shows that DR-ZnCaMo-LDH has a uniform sheet-like structure of 40-100 nm and abundant surface defects. These characteristics not only enhance sonocatalytic activity but also provide an ideal interface for cell adhesion and mineralization. This study achieved a synergistic effect between bone tumor treatment and bone regeneration through ingenious material design and preparation process, overcoming the clinical challenge of simultaneously achieving tumor clearance and tissue repair in traditional treatments. It provides an important approach for developing a new generation of integrated "treatment-regeneration" biomaterials and has broad clinical application prospects in the field of comprehensive bone tumor treatment.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing modified LDH composite material, characterized in that, Includes the following steps: Zinc salt, calcium salt, molybdenum salt, sodium hydroxide and water were mixed under a nitrogen atmosphere until the pH reached 9.

7. The resulting mixed solution was subjected to hydrothermal coprecipitation to obtain zinc-calcium-molybdenum hydrotalcite microplates ZnCaMo-LDH. Zinc-calcium-molybdenum hydrotalcite microplates were etched with sodium hydroxide to obtain etched zinc-calcium-molybdenum hydrotalcite material DR-ZnCaMo-LDH; Single colonies were picked from the preserved plates, inoculated into liquid culture medium, and cultured with shaking to obtain yeast. The prepared DR-ZnCaMo-LDH nanosheets were dispersed in 1 mL of PBS solution at a concentration of 200 μg / mL; then, at room temperature, the nanosheets were magnetically stirred into 0.5 mL of a 10% concentration solution. 8 Add 1 mL of DR-ZnCaMo-LDH solution to a CFU / mL yeast PBS solution; after incubation for 6 hours, collect the obtained yeast-LDH complex, namely Yeast@DR-ZnCaMo-LDH composite material, by centrifugation at 6000 rpm for 5 minutes, and store it in PBS solution at 4℃.

2. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The zinc salt is Zn(NO3)2·6H2O, the calcium salt is Ca(NO3)2·4H2O, and the molybdenum salt is (NH4)6Mo7O. 24 The zinc salt, calcium salt, and molybdenum salt are reacted with 4H2O in a molar ratio of 3.6:0.4:

1.

3. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The hydrothermal coprecipitation temperature was 80℃, and the reaction time was 24h.

4. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The sodium hydroxide concentration used for etching is 0.3M, the etching temperature is 120℃, and the etching time is 3h.

5. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The zinc-calcium-molybdenum hydrotalcite microsheets are hexagonal nanosheets with a size of 50-110 nm and a thickness of 17-18 nm; the etched zinc-calcium-molybdenum hydrotalcite material has a uniform sheet structure with a size of 40-100 nm.

6. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The yeast culture medium is YPD liquid culture medium.

7. The method for preparing the modified LDH composite material according to claim 1, characterized in that, The yeast was shaken at 30°C, 200 rpm, for 12-16 hours; the yeast had an OD value of 2.0 and a volume of 0.5 mL; the etched zinc-calcium-molybdenum hydrotalcite microplates had a concentration of 200 μg / mL and a volume of 1 mL; and the yeast and etched hydrotalcite microplates were stirred for 6 hours.

8. The modified LDH composite material obtained by any one of the preparation methods according to claims 1-7, characterized in that, This includes etched zinc-calcium-molybdenum hydrotalcite material and yeast.

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