Preparation method and application of bionic ceramic material based on bacterial cellulose template

Abstract

The invention discloses a preparation method and application of a bionic ceramic material based on a bacterial cellulose template. The preparation method comprises four steps of template culture, template purification, mineralization treatment and drying forming. The method comprises the following steps: firstly, accurately constructing a bacterial cellulose hydrogel template with a layered porous structure in a normal-temperature and normal-pressure liquid environment by adopting a biosynthesis method; and secondly, purifying the template to serve as a biomimetic mineralization substrate, regulating and controlling the crystallization process (including crystal form, size and orientation) of inorganic minerals by virtue of the layered confinement space of the template at normal temperature and normal pressure, and finally drying to obtain the high-toughness ceramic material with the biomimetic multilevel structure. High temperature and high pressure are not needed in the whole process, and energy consumption is remarkably reduced. The obtained bionic ceramic material has high strength (700-1700 MPa) and high modulus (21-55 GPa), and can be applied to the fields of dental restoration, bone replacement, energy-saving building materials and the like.

Description

Technical Field

[0001] This invention relates to the field of biomimetic ceramic material preparation technology, specifically to a method for preparing biomimetic ceramic materials based on bacterial cellulose templates and their applications. Background Technology

[0002] Ceramic materials, with their excellent properties such as high strength, high temperature resistance, and corrosion resistance, are widely used in aerospace, biomedicine, energy catalysis and other fields. However, traditional ceramic preparation relies on high-temperature sintering (usually >1400℃), which not only leads to extremely high energy consumption (significantly increasing production costs), but also makes it difficult to precisely control the microstructure and effectively mimic the complex multi-level structure of natural biological materials (such as the pore gradient of bones and the layered reinforcement structure of shells).

[0003] To overcome the bottlenecks in energy consumption and structural control, biomimetic mineralization technology has emerged. This technology simulates the directional crystallization process of inorganic substances in living organisms under the control of organic templates (e.g., diatom synthesis of silica, bone deposition of hydroxyapatite), enabling the synthesis of ceramic materials under near-physiological conditions (room temperature / neutral pH). Among these, the biotemplate method has become a research hotspot due to its ability to accurately replicate the fine structures of nature. However, early biotemplates (such as collagen and chitosan), while biocompatible, suffer from limitations such as poor thermal stability (carbonization temperature <400℃) and low structural strength. While plant-derived templates (such as wood and cellulose paper) possess natural hierarchical porous structures, their composition is heterogeneous (lignin interferes with mineralization) and their structural replication precision is insufficient (micron-level pores are difficult to precisely control nanoscale mineral deposition).

[0004] Therefore, the core challenge that urgently needs to be overcome is: how to prepare high-performance organic templates at room temperature and pressure? And how to utilize the inherent porous layered confinement structure within such templates to achieve precise control over the crystal form and growth direction of inorganic minerals? Ultimately, this will enable the ultra-low energy consumption preparation of biomimetic ceramic materials. Thus, this invention is derived. Summary of the Invention

[0005] In order to solve at least one of the above-mentioned technical problems, the present invention aims to provide a method for preparing biomimetic ceramic materials based on bacterial cellulose templates and their applications.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] One objective of this invention is to provide a method for preparing biomimetic ceramic materials based on bacterial cellulose templates, comprising the following steps:

[0008] Step 1), Template culture: Mix the Acetobacter xylinum bacterial culture with the nutrient solution in a certain proportion, place it in a container of selected diameter, and let it stand or be cultured in a shallow dish for a certain period of time under normal temperature and pressure to form a bacterial cellulose hydrogel membrane with a layered network structure.

[0009] Step 2), Template purification: Take out the obtained bacterial cellulose hydrogel membrane, immerse it in an alkaline solution of a certain concentration to neutralize the residual organic acids produced by bacterial metabolism, and wash it thoroughly until the membrane is neutral to obtain the purified bacterial cellulose template.

[0010] Step 3), mineralization treatment: The purified bacterial cellulose template is completely immersed in the mineralization solution and in-situ mineralization reaction is carried out for a certain period of time under normal temperature and pressure conditions.

[0011] Step 4), Drying and molding: After the mineralization reaction is completed, the composite material is taken out, washed with deionized water, and then dried to obtain a high-strength and tough biomimetic ceramic material with a layered structure.

[0012] Furthermore, the tensile strength of the biomimetic ceramic material is 700-1700 MPa, and the modulus is 21-55 GPa.

[0013] Further, in step 1), the OD of the Acetobacter xylinum bacterial solution... 600 The value is between 0.8 and 1.2;

[0014] The concentration of the nutrient solution is 0.1~0.5 g / mL, and the nutrient solution includes water, black tea and glucose, with a mass ratio of 2~10:1:0.1.

[0015] Further, in step 1), the ratio of the Acetobacter xylinum bacterial solution to the nutrient solution is 1~5:1.

[0016] Furthermore, in step 1), the incubation time at room temperature and pressure is 3 to 30 days; and / or

[0017] The diameter of the selected container is 5 to 20 cm.

[0018] Furthermore, in step 2), the alkaline solution is one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0019] Furthermore, in step 3), the concentration of the mineralizing solution is 0.1~1mM.

[0020] Furthermore, in step 3), the in-situ mineralization reaction time is 3~12 h.

[0021] Another object of the present invention is to provide biomimetic ceramic materials obtained by any of the above preparation methods.

[0022] Another objective of this invention is to provide the application of biomimetic ceramic materials prepared by any of the above-described methods in the fields of dental restoration, bone tissue replacement, and green building materials.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) In this embodiment of the invention, a layered bacterial cellulose hydrogel membrane is prepared controllably in a liquid environment at room temperature and pressure using a biosynthesis method. By adjusting the culture parameters (such as the ratio of bacterial culture to nutrient solution, nutrient solution concentration, culture container diameter, and culture time), the thickness and structural characteristics of the template can be effectively controlled. The unique layered confined space of this template provides a precisely regulated microenvironment for the subsequent mineralization process.

[0025] (2) In this embodiment of the invention, biomimetic mineralization is performed using a purified bacterial cellulose layered template. Under normal temperature and pressure conditions, the layered confined structure inside the template can effectively regulate the crystal form (e.g., inducing metastable aragonite or stable calcite / hydroxyapatite), crystal orientation, and size of inorganic minerals (such as calcium carbonate, calcium phosphate, etc.), forming a shell-like "brick-and-mortar" multi-level composite structure, endowing the material with excellent mechanical properties. The entire process does not require high temperature and high pressure, significantly reducing energy consumption.

[0026] (3) In the embodiments of the present invention, the resulting biomimetic ceramic material has high strength (up to 1700 MPa) and high modulus (up to 55 GPa), and its performance is derived from the precise layered structure and the orderly arrangement of mineral crystals. This material shows broad application prospects in the fields of dental restoration, bone tissue replacement, and green building materials. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart illustrating the preparation method of the biomimetic ceramic material according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram illustrating the preparation of the bacterial cellulose hydrogel membrane according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram illustrating the preparation of biomimetic ceramic materials according to an embodiment of the present invention;

[0031] Figure 4This is a diagram illustrating the control of bacterial film thickness in an embodiment of the present invention.

[0032] Figure 5 This is a scanning electron microscope (SEM) image of the bacterial cellulose hydrogel membrane of Example 1 of the present invention;

[0033] Figure 6 The X-ray diffraction (XRD) pattern of the biomimetic ceramic material of Example 1 of the present invention;

[0034] Figure 7 This is a cross-sectional SEM image of the biomimetic ceramic material of Embodiment 1 of the present invention;

[0035] Figure 8 These are stress-strain curves of the biomimetic ceramic materials in Examples 1-8 of this invention;

[0036] Figure 9 This is a performance comparison diagram of the biomimetic ceramic material of Embodiment 1 of the present invention with other typical layered structure materials;

[0037] Figure 10 The stress-strain curve of the biomimetic ceramic material in Comparative Example 1 is shown.

[0038] Figure 11 The stress-strain curve of the biomimetic ceramic material in Comparative Example 2 is shown.

[0039] Figure 12 The stress-strain curve of the biomimetic ceramic material in Comparative Example 3 is shown.

[0040] Figure 13 The stress-strain curve of the biomimetic ceramic material in Comparative Example 4 is shown. Detailed Implementation

[0041] In view of the shortcomings of the existing technology, the inventors of this case, through long-term research and extensive practice, have proposed a method for preparing biomimetic ceramic materials based on bacterial cellulose templates and their applications.

[0042] The following description, in conjunction with preferred embodiments and accompanying drawings, further explains and illustrates the technical solution, its implementation process, and its principles. It should be particularly noted that the following embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention.

[0043] In implementing this invention, the applicant discovered that existing technologies for preparing mineralized ceramic powders, mineralized ceramic films, and biomimetic bulk ceramics still suffer from high energy consumption and high emissions due to high temperatures or pressures. Therefore, this invention provides a method for preparing biomimetic ceramic materials based on bacterial cellulose templates. The core of this method lies in: firstly, using a biosynthetic approach to precisely construct a layered porous bacterial cellulose hydrogel template in a room-temperature, room-pressure liquid environment. Secondly, using this template as a biomimetic mineralization substrate, under room temperature and pressure, the crystallization process of inorganic minerals (including crystal form, size, and orientation) is controlled through its layered confined space. Finally, a high-strength and high-toughness ceramic material with a biomimetic multi-level structure is obtained through drying. This preparation method significantly reduces energy consumption, and the biomimetic ceramic material prepared by this method can be applied to fields such as dental restoration, bone replacement, and energy-saving building materials.

[0044] Specifically, the method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this invention embodiment, such as... Figure 1 As shown, it includes the following steps (S1 to S4):

[0045] Step 1), Template culture: Mix Acetobacter xylinum bacterial culture with nutrient solution in a certain proportion, place it in a container of selected diameter, and incubate it at room temperature and pressure for a certain period of time in a static or shallow dish to form a bacterial cellulose (BC) hydrogel membrane with a layered network structure.

[0046] Step 2), Template purification: Take out the obtained BC hydrogel membrane, immerse it in a 5% alkaline solution to neutralize the residual organic acids produced by bacterial metabolism, and wash it thoroughly until the membrane is neutral (pH≈7.0) to obtain the purified BC template;

[0047] Step 3), mineralization treatment: The purified BC template is completely immersed in the mineralization solution and in-situ mineralization reaction is carried out for a certain period of time under normal temperature and pressure conditions;

[0048] Step 4), Drying and molding: After the mineralization reaction is completed, the composite material is taken out, washed with deionized water, and then dried to obtain a high-strength and tough biomimetic ceramic material with a layered structure.

[0049] In other words, in this embodiment of the invention, Acetobacter xylinum bacterial solution is mixed with nutrient solution and cultured in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane. The thickness of the bacterial cellulose hydrogel membrane can be controlled by changing the ratio of Acetobacter xylinum bacterial solution to nutrient solution and the concentration of nutrient solution. The obtained bacterial membrane is immersed in an alkaline solution to neutralize residual acid and purify it to neutral. The purified bacterial membrane is placed in a mineralization solution and subjected to in-situ mineralization reaction under room temperature and pressure conditions. The porous layered confinement structure inside the membrane is used to control the crystal form and crystal growth direction of inorganic minerals. After drying, a high-strength and tough biomimetic ceramic material with a layered structure is obtained.

[0050] The preparation method of this invention utilizes biosynthesis to precisely construct an organic matrix template under normal temperature, pressure, and liquid conditions. This template is then used as a biomimetic mineralization template to precisely control the crystal morphology, size, and crystal arrangement of inorganic mineral materials. The biomimetic ceramic material prepared by this method exhibits high strength and high modulus (tested to have a tensile strength of 700-1700 MPa and a modulus of 21-55 GPa). This material shows broad application prospects in fields such as dental restoration (strength 300-350 MPa, modulus approximately 18 GPa), bone tissue replacement (strength 100-200 MPa, modulus approximately 30 GPa), and green building materials (strength 70-100 MPa, modulus approximately 20 GPa).

[0051] In embodiments of the present invention, the applicant has discovered through research that the ratio of *Acetobacter xylinum* bacterial culture to nutrient solution, the concentration of the nutrient solution, the diameter of the container for culturing the bacterial cellulose hydrogel membrane, and the culturing time of the bacterial cellulose hydrogel membrane are key factors affecting the thickness and mechanical properties of the membrane. An appropriate ratio can ensure the performance of the membrane and provide a structural basis for subsequent mineralization. Therefore, in some preferred embodiments, in step 1), the OD of the *Acetobacter xylinum* bacterial culture is... 600 The value is between 0.8 and 1.2; more preferably, the OD value of the Acetobacter xylinum bacterial culture is between 0.8 and 1.2. 600The value is 1.0. In some preferred embodiments, the concentration of the nutrient solution is 0.1~0.5 g / mL, and more preferably, the concentration of the nutrient solution is 0.1 g / mL. In some preferred embodiments, the nutrient solution includes water, black tea, and glucose, and the mass ratio of the three is 2~10:1:0.1. The black tea is a common variety of black tea available on the market, such as Qimen Gongfu black tea, Dianhong, Zhengshan Xiaozhong, Jinjunmei, etc., and the specific age is not limited. The glucose is also a conventional glucose available on the market. The water is deionized water or sterile water. During preparation, glucose and black tea leaves are added to boiling water and boiled for 15 minutes. After filtering to remove the tea leaves, the mixture is cooled and refrigerated. In some preferred embodiments, in step 1), the ratio of *Acetobacter xylinum* bacterial solution to the nutrient solution is 1~5:1. Exemplarily, the ratio of *Acetobacter xylinum* bacterial solution to the nutrient solution is 5:1, 2.5:1, 1.6:1, 1.25:1, 1:1. More preferably, the ratio of *Acetobacter xylinum* bacterial culture to the nutrient solution is 1:1. In some preferred embodiments, in step 1), the incubation time in a liquid environment at room temperature and pressure is 3 to 30 days. More preferably, considering both cost and the mechanical properties of the hydrogel membrane, the incubation time at room temperature and pressure is 3 days. In some preferred embodiments, the diameter of the selected container is 5 to 20 cm. More preferably, the diameter of the selected container is 10 cm.

[0052] In embodiments of the present invention, the acidity of the bacterial film affects the subsequent mineralization process. An appropriate alkaline solution is beneficial for regulating the pH of the bacterial film, thereby promoting the subsequent mineralization process. The specific alkaline solution can be selected according to the needs. The appropriate alkaline solution refers to the type of alkaline solution, such as aqueous solutions of NaOH, KOH and NH4OH.

[0053] It should be noted that during in-situ mineralization with the addition of a mineralizing solution, the confined space formed by the layered fiber network within the bacterial cellulose biofilm template plays a crucial regulatory role in the diffusion, nucleation, and crystal growth of inorganic ions (such as Ca²⁺ / CO₃²⁻ or Ca²⁺ / PO₄³⁻) in the solution, guiding minerals to deposit on the fiber surface and in the interlayer space with specific crystal forms, orientations, and sizes. In the embodiments of this invention, the applicant has found that the concentration of the mineralizing solution and the mineralization time are key factors affecting the growth of inorganic mineral crystal forms. High-concentration mineralizing solutions dominate the growth of metastable crystal forms, such as amorphous calcium carbonate and aragonite; low-concentration mineralizing solutions dominate the growth of stable crystal forms, such as calcite and hydroxyapatite; excessively high or low mineralizing solution concentrations prevent the formation of multi-level composite structures resembling shell layers. Therefore, in some preferred embodiments, in step 3), the concentration of the mineralizing solution is 0.1~1mM. The existing mineralizing solutions contain Ca... 2+ and CO3 2-The mineralization solution. More preferably, the concentration of the mineralization solution is 0.5 mM. In some preferred embodiments, in step 3), the in-situ mineralization time is 3-12 h. More preferably, the in-situ mineralization time is 6 h.

[0054] In step 4) of this embodiment, the drying method employs conventional methods such as freeze-drying, supercritical drying, or room temperature drying. Freeze-drying is preferred in this embodiment.

[0055] The present invention will be further illustrated below through specific embodiments, comparative examples, and related test experiments. In the following detailed description, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Moreover, the details in the following embodiments can be arbitrarily combined to form other feasible embodiments without conflict. All instruments, consumables, and reagents used in the following embodiments are commercially available unless otherwise specified.

[0056] Example 1

[0057] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0058] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0059] (2) The obtained bacterial film was immersed in sodium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0060] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.5 mM and the mineralization time was 6 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0061] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0062] Example 2

[0063] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0064] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0065] (2) The obtained bacterial film was immersed in sodium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0066] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.5 mM and the mineralization time was 9 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0067] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0068] Example 3

[0069] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0070] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0071] (2) The obtained bacterial film was immersed in potassium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0072] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.25 mM and the mineralization time was 6 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0073] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0074] Example 4

[0075] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0076] (1) Mix Acetobacter xylinum bacterial culture with nutrient solution at a ratio of 1:1. The concentration of nutrient solution is 0.1 g / mL. The diameter of the container for culturing bacterial cellulose hydrogel membrane is 10 cm. The culture time is 5 days. Cultivate in a liquid environment at room temperature and pressure to form bacterial cellulose hydrogel membrane.

[0077] (2) The obtained bacterial film was immersed in sodium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0078] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.5 mM and the mineralization time was 6 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0079] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0080] Example 5

[0081] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0082] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0083] (2) The obtained bacterial film was immersed in potassium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0084] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.1 mM and the mineralization time was 6 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0085] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0086] Example 6

[0087] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0088] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0089] (2) The obtained bacterial film was immersed in potassium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0090] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 1 mM and the mineralization time was 6 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0091] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0092] Example 7

[0093] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0094] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0095] (2) The obtained bacterial film was immersed in potassium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0096] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.5 mM and the mineralization time was 3 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0097] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0098] Example 8

[0099] The method for preparing biomimetic ceramic materials based on bacterial cellulose templates provided in this embodiment includes the following steps:

[0100] (1) Mix the Acetobacter xylinum bacterial culture with the nutrient solution at a ratio of 1:1. The concentration of the nutrient solution is 0.1 g / mL. The diameter of the container for culturing the bacterial cellulose hydrogel membrane is 10 cm. The culture time is 3 days. Cultivate in a liquid environment at room temperature and pressure to form a bacterial cellulose hydrogel membrane.

[0101] (2) The obtained bacterial film was immersed in potassium hydroxide solution to neutralize the residual acid and purify it to neutral;

[0102] (3) The purified bacterial membrane was placed in the mineralization solution and in-situ mineralization reaction was carried out under normal temperature and pressure conditions. The concentration of the mineralization solution was 0.5 mM and the mineralization time was 12 h. The internal porous layered confined structure was used to regulate the crystal form and crystal growth direction of inorganic minerals.

[0103] (4) After mineralization, the material is dried to obtain a biomimetic ceramic material with a layered structure.

[0104] Comparative Example 1

[0105] The preparation method of the biomimetic ceramic material provided in this comparative example differs from that in Example 1 in that it does not include a template purification step. Testing revealed that the BC hydrogel membrane in this comparative example contained numerous impurities, resulting in unsatisfactory mineralization and consequently, lower performance of the obtained material.

[0106] Comparative Example 2

[0107] The preparation method of the biomimetic ceramic material provided in this comparative example differs from that in Example 1 in that the mineralization reaction time in the mineralization treatment step is 24 hours. Testing revealed that the excessively long mineralization time led to the deposition of inorganic minerals on the surface of the bacterial cellulose template, resulting in an unsatisfactory mineralization effect.

[0108] Comparative Example 3

[0109] The preparation method of the biomimetic ceramic material provided in this comparative example differs from that in Example 1 in that the concentration of the mineralizing solution is 0.01 M (i.e., 10 mM), which means that the concentration of the mineralizing solution is higher than that in the example. As a result, the mineralization effect of the material is not ideal.

[0110] Comparative Example 4

[0111] The preparation method of the biomimetic ceramic material provided in this comparative example differs from that in Example 1 in that the concentration of the mineralizing solution is 1 M (i.e., 1000 mM), which is much higher than that in the example. As a result, the mineralization effect of the material was not ideal after testing.

[0112] Furthermore, the composite materials obtained in the above embodiments and comparative examples were subjected to structural characterization and performance testing.

[0113] The morphology of bacterial cellulose biofilms was characterized using scanning electron microscopy (SEM), such as... Figure 5 As shown, the bacterial film exhibits a layered structure. When magnified, each layer can be seen to be a porous three-dimensional network structure.

[0114] X-ray diffraction was used to analyze the in-situ mineralized bacterial cellulose, such as... Figure 6 As shown, compared with pure bacterial cellulose, the mineralized bacterial cellulose exhibits aragonite structure (1 1 1) crystal peaks, and it is preliminarily determined that in-situ mineralization of bacterial cellulose yields calcium carbonate with an aragonite structure.

[0115] Figure 7This is a scanning electron microscope image of the biomimetic mineralized ceramic material in Embodiment 1 of the present invention. After mineralization, inorganic minerals fully fill the porous structure, forming a dense layered structure similar to a seashell.

[0116] Figure 8 The stress-strain curves of the biomimetic ceramic materials in Examples 1-7 of the present invention show that the strength of the mineralized bacterial cellulose membrane in Example 1 of the present invention can reach 1700 MPa, which is far greater than that of the pure bacterial cellulose membrane and also significantly better than the biomimetic ceramic materials in Comparative Examples 1-4.

[0117] Figure 9 The figure shows a performance comparison between the biomimetic ceramic material of Example 1 of the present invention and other typical layered structure materials reported so far. It can be seen from the figure that the biomimetic ceramic material synthesized in Example 1 of the present invention exhibits an extraordinary strength-modulus combination, and its performance surpasses that of most synthetic materials. Its tensile strength is 11 times that of natural seashells, providing a key reference for the design of biomimetic composite materials.

[0118] Figures 10 to 13 The figures show the stress-strain curves of the biomimetic ceramic materials in Comparative Examples 1-4 of this invention. As can be seen from the figures, the strength of the materials in the comparative examples is much lower than that of the biomimetic ceramic material in Example 1 of this invention. This is because when the mineralization solution concentration is too high, minerals easily deposit on the surface of the bacterial film, dominating the growth of metastable crystal forms such as amorphous calcium carbonate and aragonite; when the mineralization solution concentration is too low, it dominates the growth of stable crystal forms such as calcite and hydroxyapatite, neither of which can form a multi-level composite structure similar to shell layers, thus resulting in lower performance.

[0119] Table 1. Comparison of strength and modulus values ​​of biomimetic ceramic materials obtained in Examples 1-8 and Comparative Examples 1-4 of the present invention.

[0120]

[0121] Table 2. Performance comparison between biomimetic ceramic materials and existing synthetic materials in Example 1

[0122]

[0123] As can be seen from Table 1, the properties (including tensile strength and modulus) of the biomimetic ceramic materials of Examples 1-8 of the present invention are all higher than those of Comparative Examples 1-4, especially the properties (including tensile strength and modulus) of the biomimetic ceramic material of Example 1 of the present invention are much higher than those of Comparative Examples 1-4. As can be seen from Table 2, the properties of the biomimetic ceramic material of Example 1 of the present invention are higher than those of materials used in tooth repair, bone tissue replacement, and green building materials. Furthermore, combining Tables 1 and 2, it can be seen that the properties of the biomimetic ceramic materials of Examples 2 to 8 also meet the performance requirements for materials used in tooth repair, bone tissue replacement, and green building materials. Therefore, the biomimetic ceramic materials prepared in the embodiments of the present invention have high toughness and are expected to show broad application prospects in these fields.

[0124] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0125] The use of headings and sections in this invention is not intended to limit the invention; each section can be applied to any aspect, embodiment or feature of the invention.

[0126] Throughout this invention, wherever a composition is described as having, containing, or including specific components, or wherever a process is described as having, containing, or including specific process steps, it is contemplated that the compositions taught in this invention are also substantially composed of or comprised of the described components, and that the processes taught in this invention are also substantially composed of or comprised of the described process steps.

[0127] Unless otherwise specifically stated, the use of the terms “include, include, including” or “have, has, or having” should generally be understood as open-ended and non-restrictive.

[0128] It should be understood that the order of the steps or the order in which specific actions are performed is not particularly important, as long as the teachings of this invention remain operable. Furthermore, two or more steps or actions can be performed simultaneously.

[0129] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for preparing biomimetic ceramic materials based on bacterial cellulose templates, characterized in that, Includes the following steps: Step 1), Template culture: Mix the Acetobacter xylinum bacterial culture with the nutrient solution in a certain proportion, place it in a container of selected diameter, and let it stand or be cultured in a shallow dish for a certain period of time under normal temperature and pressure to form a bacterial cellulose hydrogel membrane with a layered network structure. Step 2), Template purification: Take out the obtained bacterial cellulose hydrogel membrane, immerse it in an alkaline solution of a certain concentration to neutralize the residual organic acids produced by bacterial metabolism, and wash it thoroughly until the membrane is neutral to obtain the purified bacterial cellulose template. Step 3), mineralization treatment: The purified bacterial cellulose template is completely immersed in the mineralization solution and in-situ mineralization reaction is carried out for a certain period of time under normal temperature and pressure conditions. Step 4), Drying and molding: After the mineralization reaction is completed, the composite material is taken out, washed with deionized water, and then dried to obtain a high-strength and tough biomimetic ceramic material with a layered structure.

2. The preparation method according to claim 1, characterized in that, The biomimetic ceramic material has a tensile strength of 700-1700 MPa and a modulus of 21-55 GPa.

3. The preparation method according to claim 1, characterized in that, In step 1), the OD of the Acetobacter xylinum bacterial solution 600 The value is between 0.8 and 1.2; The concentration of the nutrient solution is 0.1~0.5 g / mL, and the nutrient solution includes water, black tea and glucose, with a mass ratio of 2~10:1:0.

1.

4. The preparation method according to claim 1 or 3, characterized in that, In step 1), the ratio of the Acetobacter xylinum bacterial solution to the nutrient solution is 1~5:

1.

5. The preparation method according to claim 1, characterized in that, In step 1), the incubation period at room temperature and pressure is 3 to 30 days; and / or The diameter of the selected container is 5 to 20 cm.

6. The preparation method according to claim 1, characterized in that, In step 2), the alkaline solution is one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

7. The preparation method according to claim 1, characterized in that, In step 3), the concentration of the mineralizing solution is 0.1~1mM.

8. The preparation method according to claim 1 or 7, characterized in that, In step 3), the in-situ mineralization reaction time is 3~12 h.

9. The biomimetic ceramic material prepared by the preparation method according to any one of claims 1-8.

10. The application of the biomimetic ceramic material prepared by the preparation method according to any one of claims 1-8 in the fields of dental restoration, bone tissue replacement and green building materials.

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