Preparation method of inorganic nanowire with bionic enamel structure

Abstract

By introducing the microfluidic system, adjusting the reaction environment and accurately controlling the synthesis conditions, the limitation of the prior art is successfully broken through. The micro-fluidic system can uniformly distribute the ion solution on the micro-scale, accurately regulate and control the reaction conditions, obviously improve the stability and accuracy of the reaction, and effectively avoid the quality fluctuation of the nanowire caused by the non-uniform reaction conditions in the traditional method. By adjusting variables such as temperature, solution concentration and the like, the structure of the inorganic nanowire can be regulated and controlled on the nanoscale, and then microscopic ordered arrangement of natural enamel is simulated. By introducing a self-assembly technology and a nano template technology, inorganic nanowires can be accurately arranged in space, so that the microstructure of natural enamel can be better copied. Through the combination of the technologies, the structural stability and the mechanical property of the bionic inorganic nanowire are remarkably improved, and a wide prospect is opened up for application of the bionic inorganic nanowire in the fields of dental restoration and other bionic materials.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials, and specifically to a preparation method of inorganic nanowires with a biomimetic enamel structure, which is mainly applied to fields such as constructing high-performance artificial dentures and biological structural materials. Background Art

[0002] Enamel is the hardest tissue in the human body. Its special microstructure and highly mineralized composition endow it with excellent mechanical properties and wear resistance. However, once enamel is damaged due to physical wear or chemical corrosion, it can hardly regenerate naturally. For the repair of enamel damage, the existing technologies mainly focus on two directions: physical coverage and mineralization induction, but both have certain limitations. Materials such as composite resins are widely used because of their convenient processing, but they are very different from natural enamel in terms of microstructure and mechanical properties, and lack the ability of ion transfer and mineralization induction, resulting in unsatisfactory repair effects. Hydroxyapatite coatings have good biocompatibility because of their similar structure to enamel, but their bonding force with tooth bodies is weak, and at the same time, the preparation cost is high, making it difficult to achieve wide application. Nano-composite materials have become a research hotspot due to certain improvements in their mechanical properties, but limited by the ion transfer efficiency and the ability to regulate biomimetic mineralization, their performance still fails to meet the clinical requirements.

[0003] In recent years, the research on biomimetic materials has provided a new technical direction for enamel repair, especially in the application of inorganic nanowires. Inorganic nanowires can accurately mimic the ordered arrangement of natural enamel at the microscale and possess excellent mechanical properties and biocompatibility. However, this type of technology is still in its infancy, and many key issues remain unresolved, particularly in the synthesis and control of inorganic nanowires. Traditional synthesis methods mostly rely on solution methods or high-temperature curing processes. Although nanowire structures can be obtained, there are significant fluctuations in terms of size, alignment direction, and crystal structure consistency, resulting in unstable properties of the obtained materials. In addition, current research has not fully explored how to achieve fine structural regulation during the growth process of inorganic nanowires. Although there are some methods to prepare inorganic nanowires, most studies mainly focus on the size, morphology, and basic properties of the nanowires, lacking precise control over the alignment direction, crystal orientation, and intermolecular interactions at the microscale. The microstructure of natural enamel exhibits a highly ordered arrangement of enamel rods, and this microscale order has an important impact on the mechanical properties and biological functions of enamel. However, existing inorganic nanowire synthesis methods often fail to accurately mimic this ordered structure at the nanoscale, resulting in the prepared biomimetic materials not achieving ideal effects in terms of mechanical strength, stability, and wear resistance. At the same time, the complex relationship between the growth conditions and reaction mechanisms of nanowires has not been deeply studied. Especially in terms of how to finely adjust the microstructure of nanowires through external regulation (such as temperature, pH value, solution concentration, etc.), there are still significant research gaps. The present invention breaks through these technical bottlenecks by introducing a microfluidic system, regulating the reaction environment, and precisely controlling the synthesis conditions. The microfluidic system can uniformly distribute ionic solutions at the microscale and precisely adjust reaction parameters, thereby improving the stability and precision of the reaction and effectively avoiding the quality fluctuations of nanowires caused by uneven conditions in traditional methods. By adjusting reaction conditions such as temperature and solution concentration, the structural regulation of inorganic nanowires can be achieved at the nanoscale, mimicking the microscale order of natural enamel. In addition, the introduction of self-assembly and nanotemplate technologies helps to achieve the precise alignment of nanowires in space, enabling them to better mimic the microscale of natural enamel. Combining these technical means can significantly enhance the structural stability and mechanical properties of biomimetic inorganic nanowires, thereby expanding their application potential in the fields of dental restoration and other biomimetic materials. Summary of the Invention

[0004] The present invention has successfully overcome the limitations of the existing technology by introducing a microfluidic system, regulating the reaction environment, and precisely controlling the synthesis conditions. The microfluidic system can uniformly distribute ionic solutions at the microscale, precisely regulate the reaction conditions, significantly improve the stability and precision of the reaction, and effectively avoid the quality fluctuations of nanowires caused by uneven reaction conditions in traditional methods. By adjusting variables such as temperature and solution concentration, the structural regulation of inorganic nanowires can be achieved at the nanoscale, and then the microscopically ordered arrangement of natural tooth enamel can be simulated. The introduction of self-assembly technology and nano-template technology enables the precise spatial arrangement of inorganic nanowires, thus better replicating the microstructure of natural tooth enamel. Through the combination of these technologies, the structural stability and mechanical properties of the biomimetic inorganic nanowires have been significantly improved, which opens up broad prospects for their application in dental restoration and other fields of biomimetic materials.

[0005] Step 1: Dissolve a certain amount of calcium salt precursor in a solvent at a certain temperature. Precisely regulate the dissolution rate and flow rate through the microfluidic system to ensure the uniformity and stability of the precursor solution, and stir for a certain period of time to obtain Component A.

[0006] Step 2: Add a certain amount of metal salt, complex, or other mineralization inducer to Component A. Use self-assembly regulation technology to uniformly distribute metal ions in the microfluidic environment. These components can serve as nucleation sources or initiators in the mineralization reaction. Enhance the interaction between ions through auxiliary activation technologies (such as ultrasonic, microwave, or ultraviolet light irradiation), promote the orderly deposition of metal ions in the solution and form a preliminary structure, and stir until a stable nanostructure is formed.

[0007] Step 3: Dissolve a specific proportion of phosphate in a solvent, and adopt nano-confined reaction conditions. Control the deposition process through low-speed stirring to obtain Component B.

[0008] Step 4: Dissolve a certain amount of regulatory additive in a solvent, place it in the microfluidic system, and precisely control the flow rate and mixing conditions to ensure the uniformity of the solution to obtain Component C.

[0009] Step 5: Mix Component A, Component B, and Component C in a certain proportion in a micro-reaction system, and react under controlled conditions through a temperature control gradient module. Use photocuring technology to promote the gelation process to obtain chiral biomimetic tooth enamel with highly stable structure.

[0010] The calcium salt precursor in Step 1 can be an inorganic calcium salt (such as calcium chloride, calcium nitrate, calcium sulfate, calcium acetate, calcium carbonate) or an organic calcium complex (such as calcium citrate, calcium gluconate, calcium lactate). The solvent can be water, ethanol, methanol, isopropanol, acetone, or a combination thereof. The dissolution temperature is between 10-60°C, and the stirring time is 0.5-12 hours.

[0011] The metal salts, complexes or other mineralization inducers in the second step: may include metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium nitrate, sodium chloride, sodium nitrate, potassium chloride, potassium nitrate, etc., or complexes formed by calcium salts and organic acids, such as calcium citrate, calcium gluconate, calcium lactate, calcium malate, calcium oxalate, etc. These substances help to promote the mineralization reaction and form a stable nuclear structure. In addition, other metal ions can also be used, such as zinc ions (Zn 2+ ), and zinc chloride and zinc sulfate sourced therefrom, magnesium ions (Mg 2+ ), and magnesium chloride and magnesium sulfate sourced therefrom, iron ions (Fe 3+ ), and ferric chloride and ferric sulfate sourced therefrom, etc., as regulatory components in the mineralization process. By controlling factors such as ion concentration and flow rate through a microfluidic system, these components can be evenly distributed in the solution. The reaction temperature is usually between 20 - 70 °C, and the stirring time is 30 minutes to 2 hours. The phosphate in the third step can be sodium phosphate, potassium phosphate, potassium dihydrogen phosphate, calcium phosphate, tricalcium phosphate, sodium pyrophosphate, etc., and their complexes. The dissolution temperature is between 20 - 60 °C, and it is stirred at a low speed for 1 - 4 hours.

[0012] The regulatory additives in the fourth step may include polyethylene glycol, ethanolamine, sodium citrate, sodium salts (such as sodium acetate, sodium lactate, sodium carbonate) or other small molecule surfactants, and the solvent can be water, ethanol, methanol, dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and other polar organic solvents.

[0013] The reaction conditions in the fifth step include the temperature being controlled between 50 - 200 °C, the reaction time being 1 - 24 hours, and the light curing technology can select ultraviolet light or visible light source.

[0014] A kind of biomimetic enamel inorganic nanowire prepared by the present invention has the following advantages:

[0015] (1) Microfluidic system and precise reaction control: The microfluidic system can precisely regulate the flow rate and distribution of ionic solutions at the microscale, ensuring the uniformity and stability of the reaction process, thereby optimizing the growth process and structural characteristics of inorganic nanowires.

[0016] (2) Application of nano-confined reaction conditions: By adopting nano-confined reaction conditions, the deposition process is effectively controlled, ensuring the orderly arrangement of inorganic nanowires at the microscale, and significantly improving the mineralization efficiency and mechanical properties of the material.

[0017] (3) Excellent mechanical properties and structural stability: Combining with light curing technology, the inorganic nanowire material provided by the present invention shows excellent performance in terms of hardness, wear resistance and compressive strength, is suitable for long-term use and high-load conditions, and has excellent application prospects especially in dental restoration.

[0018] (4) Wide range of application fields: The bionic enamel inorganic nanowires not only exhibit excellent performance in dental materials but also have broad application potential, especially in multiple fields such as artificial dentures, bionic bones, and coating materials, with good market prospects.

[0019] (5) Environment-friendly and economical: The raw materials used in this invention are widely sourced and environmentally friendly. The entire preparation process does not rely on high temperatures or toxic solvents, conforming to the principles of green chemistry, having high potential for industrial production, and helping to reduce production costs. In summary, this invention provides an innovative method for the preparation of bionic enamel inorganic nanowires, which not only improves the performance and repair effect of the materials but also opens up a new direction for the research and development of future bionic structural materials. Brief Description of the Drawings

[0021] Figure 1 : Bionic enamel structure inorganic nanowires synthesized by the method of Example 1

[0023] Figure 2 : Performance comparison of the material hardness, compressive strength, wear resistance, and mineralization efficiency between a bionic enamel structure inorganic nanowire and other inorganic nanomaterials and traditional enamel repair materials Detailed Embodiments

[0024] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further details the present invention in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely used to explain the present invention and are not used to limit the present invention.

[0025] A preparation method of a bionic enamel inorganic nanowire provided by an embodiment of the present invention includes the following steps

[0026] 1. Dissolve a certain amount of calcium salt precursor in a solvent at a certain temperature, precisely control the dissolution rate and flow rate through a microfluidic system to ensure the uniformity and stability of the precursor solution, and stir for a period of time to obtain Component A. The calcium salt precursor can be an inorganic calcium salt (such as calcium chloride, calcium nitrate, calcium sulfate, calcium acetate, calcium carbonate) or an organic calcium complex (such as calcium citrate, calcium gluconate, calcium lactate), the solvent can be water, ethanol, methanol, isopropanol, acetone, or a combination thereof, the dissolution temperature is between 10 - 60 °C, and the stirring time is 0.5 - 12 hours.

[0027] 2. Add a certain amount of metal salts, complexes, or other mineralization inducing agents to Component A. Using self-assembly regulation technology, make metal ions uniformly distributed in the microfluidic environment. These components can serve as nuclear sources or initiators in the mineralization reaction. Enhance the interaction between ions through auxiliary activation techniques (such as ultrasonic waves, microwaves, or ultraviolet light irradiation), promote the orderly deposition of metal ions in the solution and form a preliminary structure, and stir until a stable nanostructure is formed. The metal salts, complexes, or other mineralization inducing agents may include metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium nitrate, sodium chloride, sodium nitrate, potassium chloride, potassium nitrate, etc., or complexes formed by calcium salts and organic acids, such as calcium citrate, calcium gluconate, calcium lactate, calcium malate, calcium oxalate, etc. In addition, other metal ions can also be used, such as zinc ions (Zn 2+ ) from zinc chloride, zinc sulfate, magnesium ions (Mg 2+ ) from magnesium chloride, magnesium sulfate, iron ions (Fe 3+ ) from iron chloride, iron sulfate, etc., as regulatory components in the mineralization process. The reaction temperature is usually between 20 - 70 °C, and the stirring time is 30 minutes to 2 hours. The auxiliary activation techniques may include ultrasonic assistance (power 10 - 100 W, frequency 20 - 50 kHz), microwave assistance (power 50 - 300 W), ultraviolet light irradiation (wavelength 200 - 400 nm), etc.

[0028] 3. Dissolve a specific proportion of phosphates in a solvent, and adopt nano-confined reaction conditions. Control the deposition process through low-speed stirring to obtain Component B. The phosphates can be sodium phosphate, potassium phosphate, potassium dihydrogen phosphate, calcium phosphate, tricalcium phosphate, sodium pyrophosphate, etc., and their complexes. The dissolution temperature is between 20 - 60 °C, and low-speed stirring is carried out for 1 - 4 hours.

[0029] 4. Dissolve a certain amount of regulatory additives in a solvent, place it in a microfluidic system, and precisely control the flow rate and mixing conditions to ensure the uniformity of the solution to obtain Component C. The regulatory additives may include polyethylene glycol, ethanolamine, sodium citrate, sodium salts (such as sodium acetate, sodium lactate, sodium carbonate), or other small molecule surfactants. The solvent can be polar organic solvents such as water, ethanol, methanol, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), etc.

[0030] 5. Mix Component A, Component B, and Component C in a certain proportion in a microreaction system, and react under controlled conditions through a temperature control gradient module. Utilize photocuring technology to promote the gelation process. The reaction conditions include controlling the temperature between 50 - 200 °C, and the reaction time is 1 - 24 hours. The photocuring technology can select ultraviolet light or visible light sources.

[0031] The present invention will be further described below in conjunction with specific embodiments.

[0032] Example 1

[0033] Dissolve 2 g of calcium chloride in 100 mL of deionized water. Control the solution flow rate through a microfluidic system, keep the temperature at 25 °C, and stir for 1 hour to obtain Component A. Add 0.1 g of calcium chloride as a metal salt and react for 30 minutes under ultrasonic assistance at 20 kHz and 50 W. Dissolve 1 g of sodium phosphate in 50 mL of water and drop it into Solution A at a rate of 0.5 mL / min, and stir for 2 hours under nano-confinement conditions to obtain Component B. Dissolve 0.5 g of polyethylene glycol in water to obtain Component C. Mix Components A, B, and C in a volume ratio of 2:1:1 and treat them in a photocuring device at 100 °C for 3 hours to prepare biomimetic enamel inorganic nanowires.

[0034] Example 2

[0035] Dissolve 3 g of calcium nitrate in 100 mL of deionized water, control the temperature at 30 °C, regulate the flow rate through a microfluidic system, and stir for 2 hours to obtain Component A. Add 0.2 g of calcium nitrate and stir for 40 minutes through microwave-assisted technology with a power of 100 W. Dissolve 0.5 g of potassium dihydrogen phosphate in 40 mL of ethanol and add it to Solution A at a rate of 0.3 mL / min, and stir at a low speed for 3 hours to obtain Component B. Dissolve 0.2 g of sodium citrate in 20 mL of water to obtain Component C. Mix Components A, B, and C in a volume ratio of 1:2:1 and treat them in a photocuring device at 120 °C for 4 hours to prepare biomimetic enamel inorganic nanowires.

[0036] Example 3

[0037] Dissolve 1 g of calcium acetate in 80 mL of methanol, keep the temperature at 20 °C, control the flow rate with a microfluidic system, and stir for 1 hour to obtain Component A. Add 0.05 g of calcium citrate as a mineralization inducer and stir for 15 minutes under ultraviolet light irradiation conditions (320 nm) to promote self-assembly. Dissolve 0.5 g of sodium pyrophosphate in 30 mL of ethanol and add it to Solution A at a rate of 0.2 mL / min, and stir at a low speed for 1 hour to obtain Component B. Dissolve 0.1 g of sodium lactate in water to obtain Component C. Mix Components A, B, and C in a volume ratio of 1:1:1 and place them in a photocuring device at 80 °C for 2 hours to prepare biomimetic enamel inorganic nanowires.

[0038] Example 4

[0039] Dissolve 2 g of calcium citrate in 100 mL of dimethyl sulfoxide (DMSO), control the temperature at 40 °C, regulate the solution flow rate through a microfluidic system, and stir for 1 hour to obtain Component A. Add 0.15 g of calcium lactate as a mineralization inducer and stir for 30 minutes under ultrasonic assistance at 50 W. Dissolve 1.5 g of potassium phosphate in 40 mL of deionized water, dropwise add it at a rate of 0.7 mL / min, and stir for 3 hours to obtain Component B. Dissolve 0.25 g of sodium acetate in water to obtain Component C. Mix A, B, and C in a volume ratio of 1:1:2 and treat them in a photocuring device at 110 °C for 3 hours.

[0040] Example 5

[0041] Dissolve 3 g of calcium sulfate in a mixed solvent of 120 mL of ethanol and water (volume ratio 1:1), control the temperature and flow rate through a microfluidic system, control the temperature at 25 °C, and stir for 2 hours to obtain Component A. Add 0.2 g of zinc sulfate and stir for 45 minutes under ultrasonic assistance at a frequency of 30 kHz. Dissolve 0.75 g of calcium phosphate in 20 mL of water and dropwise add it at a rate of 0.3 mL / min under nano-confined conditions, and stir for 3 hours to obtain Component B. Dissolve 0.3 g of sodium citrate in 10 mL of ethanol to obtain Component C. Mix A, B, and C in a volume ratio of 2:2:1 and treat them in a photocuring reactor at 130 °C for 3 hours to prepare biomimetic enamel inorganic nanowires.

[0042] Example 6

[0043] Dissolve 4 g of calcium carbonate in 100 mL of acetone, regulate the solution flow rate through a microfluidic system, control the temperature at 35 °C, and stir for 2 hours to obtain Component A. Add 0.1 g of L-cysteine and 0.05 g of zinc chloride as mineralization inducers and stir for 30 minutes under microwave-assisted technology (power 75 W). Dissolve 2 g of tricalcium phosphate in 30 mL of water, dropwise add it to Solution A at a rate of 0.4 mL / min, and stir under nano-confined conditions for 4 hours to obtain Component B. Dissolve 0.5 g of polyethylene glycol in water to obtain Component C. Mix A, B, and C in a volume ratio of 3:1:1 and treat them in a photocuring device at 90 °C for 3 hours.

[0044] Example 7

[0045] Dissolve 1 g of calcium gluconate in 100 mL of water, control the temperature at 30 °C, control the solution flow rate through a microfluidic system, and stir for 1 hour to obtain Component A. Add 0.1 g of magnesium chloride and stir for 20 minutes under ultraviolet light assistance (350 nm). Dissolve 0.5 g of sodium pyrophosphate in 40 mL of deionized water, dropwise add it at a rate of 0.6 mL / min, and stir for 2 hours to obtain Component B. Dissolve 0.25 g of ethanolamine in water to obtain Component C. Mix A, B, and C in a volume ratio of 1:2:2 and treat them in a photocuring device at 80 °C for 3 hours to prepare biomimetic enamel inorganic nanowires.

[0046] Example 8

[0047] Dissolve 3 g of calcium chloride in a mixed solvent of 80 mL of water and methanol (volume ratio 2:1). Control the temperature and flow rate through a microfluidic system. Keep the temperature at 20 °C and stir for 2 hours to obtain Component A. Add 0.2 g of ferric chloride and stir for 30 minutes with ultrasonic assistance (25 kHz, 60 W). Dissolve 0.7 g of potassium phosphate in 30 mL of water and add it dropwise at a rate of 0.8 mL / min. Stir for 3 hours under nanoconfinement conditions to obtain Component B. Dissolve 0.2 g of sodium lactate in water to obtain Component C. Mix A, B, and C in a volume ratio of 1:1:2 and treat them in a photocuring device at 100 °C for 4 hours.

[0048] Example 9

[0049] Dissolve 2 g of calcium nitrate in a mixed solvent of 90 mL of dimethyl sulfoxide (DMSO) and water (volume ratio 1:1). Control the flow rate and temperature through a microfluidic system and stir for 1 hour with the temperature controlled at 30 °C to obtain Component A. Add 0.05 g of calcium gluconate and stir for 30 minutes with microwave assistance (power 100 W). Dissolve 1 g of calcium dihydrogen phosphate in 40 mL of ethanol and add it dropwise at a rate of 0.5 mL / min. Stir for 2 hours under nanoconfinement conditions to obtain Component B. Dissolve 0.3 g of sodium acetate in water to obtain Component C. Mix A, B, and C in a volume ratio of 1:2:1 and treat them in a photocuring reactor at 120 °C for 4 hours.

[0050] Example 10

[0051] Dissolve 1 g of calcium lactate in 70 mL of water. Control the temperature at 25 °C and control the flow rate and solution uniformity through a microfluidic system. Stir for 1 hour to obtain Component A. Add 0.1 g of potassium chloride and stir for 15 minutes under ultraviolet light assistance (wavelength 300 nm). Dissolve 1 g of calcium phosphate in 20 mL of methanol and add it dropwise to the solution of A at a rate of 0.3 mL / min. Stir for 3 hours under nanoconfinement conditions to obtain Component B. Dissolve 0.2 g of sodium citrate in water to obtain Component C. Mix A, B, and C in a volume ratio of 2:1:1, place them in a photocuring reactor, and treat them at 110 °C for 2 hours to prepare biomimetic enamel nanowires.

[0052] Obviously, the above examples are only for clear illustration and not limitations on the implementation methods. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. And the obvious changes or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A preparation method of biomimetic enamel structure inorganic nanowires, characterized in that, The preparation method of the biomimetic enamel structure inorganic nanowires comprises the following steps: Step 1: Dissolve a certain amount of calcium salt precursor in a solvent at a certain temperature, precisely control the dissolution rate and flow rate through a microfluidic system to ensure the uniformity and stability of the precursor solution, and stir for a certain time to obtain Component A. Step 2: Add a certain amount of metal salt, complex or other mineralization inducer to Component A, and use self-assembly regulation technology to make metal ions uniformly distributed in the microfluidic environment. These components can serve as nucleation sources or initiators in the mineralization reaction. Enhance the interaction between ions through auxiliary activation techniques (such as ultrasonic waves, microwaves or ultraviolet light irradiation), promote the orderly deposition of metal ions in the solution and form a preliminary structure, and stir until a stable nanostructure is formed. Step 3: Dissolve a specific proportion of phosphate in a solvent, and adopt nano-confined reaction conditions, and control the deposition process by low-speed stirring to obtain Component B. Step 4: Dissolve a certain amount of regulation additive in a solvent, place it in a microfluidic system, precisely control the flow rate and mixing conditions to ensure the uniformity of the solution, and obtain Component C. Step 5: Mix Component A, Component B and Component C in a certain proportion in a micro-reaction system, and react under controlled conditions through a temperature control gradient module. Utilize photocuring technology to promote the gelation process to obtain a chiral biomimetic enamel with a highly stable structure. The calcium salt precursor in Step 1 can be an inorganic calcium salt (such as calcium chloride, calcium nitrate, calcium sulfate, calcium acetate, calcium carbonate) or an organic calcium complex (such as calcium citrate, calcium gluconate, calcium lactate), and the solvent can be water, ethanol, methanol, isopropanol, acetone or a combination thereof. The dissolution temperature is between 10-60°C, and the stirring time is 0.5-12 hours. The metal salts, complexes or other mineralization inducers in the second step: may include metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium nitrate, sodium chloride, sodium nitrate, potassium chloride, potassium nitrate, etc., or complexes formed by calcium salts and organic acids, such as calcium citrate, calcium gluconate, calcium lactate, calcium malate, calcium oxalate, etc. These substances help to promote the mineralization reaction and form a stable nuclear structure. In addition, other metal ions can also be used, such as zinc ions (Zn 2+ ) from zinc chloride, zinc sulfate, magnesium ions (Mg 2+ ) from magnesium chloride, magnesium sulfate, iron ions (Fe 3+ ) from iron chloride, iron sulfate, etc., as regulatory components in the mineralization process. By controlling factors such as ion concentration and flow rate through the microfluidic system, these components can be evenly distributed in the solution. The reaction temperature is usually between 20 - 70 °C, and the stirring time is 30 minutes to 2 hours. The phosphate in the third step can be sodium phosphate, potassium phosphate, potassium dihydrogen phosphate, calcium phosphate, tricalcium phosphate, sodium pyrophosphate and other phosphates and their complexes, with the dissolution temperature between 20 - 60 °C, and low-speed stirring for 1 - 4 hours. The regulation additive in Step 4 can include polyethylene glycol, ethanolamine, sodium citrate, sodium salts (such as sodium acetate, sodium lactate, sodium carbonate) or other small molecule surfactants, and the solvent can be water, ethanol, methanol, dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and other polar organic solvents. The reaction conditions in Step 5 include the temperature being controlled between 50-200°C, the reaction time being 1-24 hours, and the photocuring technology can select ultraviolet light or visible light source.

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