Bifunctional polymer stabilized calcium phosphate precursor nano-material, preparation method thereof and application in PPESK coating surface modification

Abstract

The invention provides a bifunctional polymer stabilized calcium phosphate precursor nano-material, a preparation method thereof and application of the bifunctional polymer stabilized calcium phosphate precursor nano-material in surface modification of a PPESK coating. The bifunctional polymer stabilized calcium phosphate precursor nano-material comprises the following components according to concentration: a bifunctional polymer with the concentration of 0.05-0.2 g / mL; the concentration of PO4 < 3-> is 0.05 to 0.5 mol / L; the concentration of Ca < 2 + > is 0.05-0.5 mol / L, and the solvent is deionized water; the diameter of the calcium phosphate precursor nano material is 20 to 100 nm. The preparation method comprises the following steps: preparing a polyacrylamide block polymer by adopting free radical polymerization, and then grafting a calcium chelating agent to obtain a bifunctional polymer; combining the difunctional polymer with a calcium-phosphorus solution to prepare a difunctional polymer stabilized calcium phosphate precursor nano material; according to the invention, the polymer is endowed with calcium chelating ability and collagenous fiber binding ability, so that the material can enter the collagenous fiber to be fully mineralized, the surface of the PPESK coating is mineralized, the biocompatibility of the material is improved, the material has osteogenesis promoting ability, and the material has a wide application prospect in the aspect of bone implant materials.

Description

Technical Field

[0001] The invention belongs to the field of biomedical materials and relates to a bifunctional polymer-stabilized calcium phosphate precursor nanomaterial, a preparation method thereof and application in surface modification of PPESK coatings. Background Art

[0002] Biomineralization is a ubiquitous phenomenon in animals, plants, and microorganisms. Through a long period of biological evolution, organisms have been able to assemble hard tissues such as teeth and bones from common mineral crystals, often composed of calcium carbonate and calcium phosphate, into multi-layered, ordered structures. Inspired by biomineralization, biomimetic mineralization utilizes the principles of biomineralization to create organic-inorganic composite materials in vitro that resemble biominerals, or to simulate biomineralization environments to investigate the mechanisms by which organic molecules regulate mineral crystallization. As research continues, a growing number of researchers have discovered amorphous mineral precursors in natural mineralized bodies, leading to a growing consensus that minerals in hard tissues are derived from these precursors. The nonclassical nucleation theory has gained widespread acceptance. In this nonclassical nucleation pathway, an amorphous mineral precursor intermediate phase undergoes a solidification process before ultimately forming crystals. This theory has laid the foundation for future research on natural bone tissue and bone replacement materials, providing new insights. Based on previous research, it was discovered that polyaspartic acid can induce the formation of amorphous calcium carbonate during the liquid-liquid separation phase. Amorphous calcium carbonate then deposits on the substrate surface, binds to form a coating, and solidifies into calcified fibers, sheets, and films with non-equilibrium crystalline structures. This has been further extended to the field of calcium phosphate mineralization, where polymers can stabilize supersaturated calcium phosphate solutions to form amorphous calcium phosphate mineral precursors. Mineralization within collagen fibrils during the mineralization process has led to the development of the polymer-induced liquid-phase precursor theory. The theory of polymer-induced liquid-phase precursors was proposed because polymers play a crucial role in the formation of amorphous mineral precursors. In the original crystalline phase of a substance, the amorphous state exists only briefly. Using polymers to mimic the effects of non-collagenous proteins can prolong the stable amorphous phase. Adding stabilizers can make the amorphous mineral precursors fluid for extended periods of time. Alternatively, introducing biomacromolecules can enable crystals to grow in an orderly, uniform pattern using collagen fibrils as templates. However, as a mineralizing solution, the binding capacity for collagen fibrils and the mineralization strength need to be improved. Summary of the Invention

[0003] The present invention proposes to use a bifunctional polymer to stabilize a calcium-phosphate solution to obtain a calcium phosphate precursor material. Through the material's ability to bind to and mineralize collagen fibers, the collagen fibers are fully mineralized internally, achieving the in vitro preparation of an organic-inorganic composite structure similar to a biomineral. The PPESK coating surface is then mineralized. The present invention aims to provide a bifunctional polymer-stabilized calcium phosphate precursor nanomaterial, its preparation method, and its application in collagen fiber mineralization. The bifunctional polymer-stabilized calcium phosphate precursor material is first prepared by free radical polymerization, followed by amidation and grafting of a calcium chelating agent. This imparts calcium chelating and collagen fiber binding capabilities to the polymer, allowing the material to fully mineralize within the collagen fibers. The PPESK coating surface is then mineralized and modified, improving the material's biocompatibility and promoting osteogenesis.

[0004] The technical solutions of the present invention are as follows:

[0005] A bifunctional polymer-stabilized calcium phosphate precursor nanomaterial, comprising the following components according to concentration: a bifunctional polymer concentration of 0.05 to 0.2 g / mL; PO4 3- The concentration is 0.05~0.5mol / L; Ca 2+ The concentration is 0.05 to 0.5 mol / L, the solvent is deionized water; the diameter of the calcium phosphate precursor nanomaterial is 20 to 100 nm;

[0006] The bifunctional polymer structure is expressed as formula (I):

[0007]

[0008] Wherein, m and n are positive integers, and R1 is the main structure of the block polymer, which is one of the following structures:

[0009]

[0010] R2 is the main structure of the calcium chelator, which is one of the following structures:

[0011]

[0012] The present invention also provides a preparation method of the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial, comprising the following steps: dissolving 0.1-0.4 g of the bifunctional polymer in deionized water, adding 10 mL of a 0.1-1.0 mol / L Na2HPO4 solution after the bifunctional polymer is fully dissolved, stirring evenly, and adjusting the pH value to 6-8 to obtain a solution A; slowly adding 10 mL of a 0.1-1.0 mol / L CaCl2 solution to the solution A, continuously stirring, and adjusting the pH value to 7.4, wherein the solution remains clear and transparent, thereby forming the calcium phosphate precursor nanomaterial in the bifunctional polymer solution.

[0013] The preparation method of the bifunctional polymer comprises the following steps:

[0014] S01 uses free radical polymerization to prepare polyacrylamide block polymers: acrylamide, an initiator, a chain transfer agent and a solvent are mixed and polymerized to obtain polyacrylamide segments; then acrylamide monomers are mixed with the polyacrylamide segments, an initiator, a chain transfer agent and a solvent and polymerized to obtain polyacrylamide block polymers, which are expressed as formula (II):

[0015]

[0016] S2 polyacrylamide block polymer grafted with calcium chelating agent: amino activation of polyacrylamide block polymer was performed using 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, followed by amidation reaction to obtain a bifunctional polymer;

[0017] The acrylamide monomer in S1 is N-(3-aminopropyl)methacrylamide, N-(3-aminophenyl)acrylamide, N-(2-aminoethyl)acrylamide or N-(2-aminoethyl)methacrylamide; the calcium chelating agent in S2 is diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid or ethylene glycol bis(2-aminoethyl ether)tetraacetic acid.

[0018] The initiator is azobisisobutyronitrile (AIBN), the chain transfer agent is 2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and the solvent is dimethyl sulfoxide.

[0019] The polymerization time of the polyacrylamide chain segment is 9 to 12 hours, the polymerization time of the polyacrylamide block polymer is 9 to 16 hours, and the molar ratio of the chain transfer agent to the initiator is 5 to 10.

[0020] The method for preparing polyacrylamide block polymer by free radical polymerization specifically comprises the following steps:

[0021] S01: 2.5-7.5 g of acrylamide, 0.05-00.15 g of chain transfer agent, and 0.014-0.03 g of initiator are dissolved in a solvent and added into a Shrek bottle. The mixture is frozen with liquid nitrogen, evacuated, and nitrogen is introduced. The polymerization reaction is carried out at 70-80° C. After the reaction, the mixture is precipitated with ethanol, filtered, and dried to obtain a polyacrylamide segment having the structural expression of formula (III):

[0022]

[0023] S02: 1.5-2.5 g of polyacrylamide chain segments, 2.5-7.5 g of acrylamide monomers, 0.05-00.15 g of chain transfer agents, and 0.014-0.03 g of initiators are dissolved in a solvent and added into a Shrek bottle. The mixture is frozen with liquid nitrogen, vacuumed, and nitrogen is introduced. The polymerization reaction is carried out at 70-80° C. After the reaction, ethanol is used to precipitate the mixture, which is then filtered and dried to obtain the polyacrylamide block polymer.

[0024] The preparation method of the polyacrylamide block polymer grafted with a calcium chelating agent specifically comprises the following steps: dissolving 1-3 g of a calcium chelating agent in 5-15 mL of deionized water, adjusting the pH to 6, adding 0.1-0.5 g of the polyacrylamide block polymer, adding 1.5-3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide after 5-15 minutes, adding 0.5-1 g of N-hydroxysuccinimide after 15 minutes, reacting at room temperature for 24-48 hours, dialysis against deionized water at 20-37° C. for 2 days, and freeze-drying in a freeze dryer to obtain a bifunctional polymer product.

[0025] The present invention also provides an application of the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial in collagen fiber mineralization. The bifunctional polymer-stabilized calcium phosphate nanomaterial has calcium and phosphorus stability, interacts with collagen fibers, and the calcium and phosphorus ions contained therein have the effect of promoting osteogenic differentiation.

[0026] The present invention also provides a PPESK material modified by a mineralized coating, including a PPESK material modified by a hydrogel coating, wherein the coating is uniformly coated with calcium and phosphorus elements as a whole, and the coating is fully mineralized.

[0027] The thickness of the hydrogel coating is 20-100 μm.

[0028] The present invention also provides a preparation method of the mineralized coating modified PPESK material, which modifies the surface of the PPESK coating, including using the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial to perform mineralization modification on the hydrogel coating modified PPESK material to obtain the mineralized coating modified PPESK material.

[0029] The hydrogel coating modified PPESK material is obtained by coating a hydrogel solution on the surface of the PPESK material and curing it with ultraviolet light; the hydrogel solution is obtained by dissolving hydrogel coating raw materials, a photoinitiator and a crosslinking agent in deionized water.

[0030] The hydrogel solution contains 1.5-2.5 g of hydrogel coating raw material, 0.05-0.2 g of photoinitiator, and 0.05-0.2 g of cross-linking agent.

[0031] The ultraviolet light curing time is 1 to 5 minutes.

[0032] The raw materials of the hydrogel coating are acrylamide and modified collagen, modified chitosan or modified gelatin, the photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and the crosslinking agent is N,N'-bis(acryloyl)cystamine.

[0033] The mineralization temperature is 25-40° C., and the mineralization time is 7-14 days.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. The material polymerization method is simple, the raw materials are easily available, and there is no pollution to the environment. The prepared materials can be used immediately.

[0036] 2. When preparing the calcium phosphate precursor material of the present invention, only one polymer needs to be added, the formula is simple, and the preparation method is simple and easy to prepare.

[0037] 3. The polyacrylamide polymer of the present invention, by grafting a calcium chelating agent, enhances its ability to chelate calcium and phosphate ions, stabilizing the calcium phosphate precursor. Furthermore, the amino segments in the block polymer improve the material's ability to bind to collagen fibers, resulting in excellent biocompatibility and osteogenic properties. It can effectively promote the mineralization of collagen fibers and has broad application prospects in the preparation of biomimetic inorganic-organic composite materials.

[0038] 4. The use of bifunctional polymer-stabilized calcium phosphate precursor nanomaterials to mineralize the hydrogel-coated PPESK material can fully mineralize the coating on the PPESK surface and improve the biocompatibility and osteogenic properties of the material, which has important research significance for the preparation of polyarylether bone implant materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 These are the NMR spectra of the three polymers during the preparation process.

[0040] Figure 2 Comparison of calcium chelating ability of different polymers.

[0041] Figure 3 Transmission electron microscope images of calcium phosphate precursor nanomaterials just after preparation and three days after preparation.

[0042] Figure 4 Images of the mineralization effects of different nanomaterials interacting with collagen fibers.

[0043] Figure 5 Confocal microscopy xy projection images of mineralized collagen fibers.

[0044] Figure 6 The results of the MTT method sample and cell co-culture test.

[0045] Figure 7 The image is from alkaline phosphatase staining experiment.

[0046] Figure 8 Cross-sectional images of PPESK materials modified with coatings of different thicknesses.

[0047] Figure 9 These are the cross-sectional images and energy spectrum analysis images of the mineralized coating modified PPESK material. DETAILED DESCRIPTION

[0048] The essential features and significant improvements of the present invention are further illustrated below through specific examples. However, the content of the present invention is not limited to the following examples and can be adjusted according to actual conditions.

[0049] The polymer structure was analyzed using proton nuclear magnetic resonance spectroscopy. The calcium chelation capacity of the material was characterized by chromium black T complexometric titration. The mineralization effect of the material on collagen fibers was characterized by transmission electron microscopy and fluorescence staining. The osteogenic properties of the material were characterized by alkaline phosphatase staining.

[0050] The collagen fibers were prepared as follows: 0.3 g of type I collagen was added to 100 mL of 3% glacial acetic acid solution and stirred vigorously in an ice-water bath for two days until the collagen dissolved. The collagen solution was then added to a 3 cm diameter mold and allowed to self-assemble under an ammonia atmosphere, subsequently forming porous collagen fibers. The porous collagen fibers were then immersed in a 0.5% glutaraldehyde solution for four hours to fix the collagen fibers.

[0051] Modified collagen was prepared as follows: 0.3 g of type I collagen was added to 100 mL of 3% glacial acetic acid solution and stirred vigorously in an ice-water bath for two days until the collagen dissolved. 3 mL of methacrylic anhydride was added to the collagen solution and reacted in an ice-water bath for four hours. The solution was then dialyzed against deionized water for two days using a 14,000-mesh dialysis bag and freeze-dried to obtain the modified collagen.

[0052] The mineralization process of collagen fibers and calcium phosphate precursor nanomaterials is as follows: the prepared collagen fibers are added to calcium phosphate precursor solutions of different materials, placed at 37°C, and allowed to stand for the mineralization reaction. After seven days, the mineralized collagen fibers are removed, rinsed with deionized water, ultrasonically cleaned for 30 minutes, and freeze-dried in a freeze dryer to obtain the mineralized collagen fibers.

[0053] Cytotoxicity test was performed as follows: First, prepare 5 mg / mL MTT solution and store at 4°C in the dark. DCAP, SBF, and HA were added to 10 mL of α-MEM medium and mixed thoroughly to obtain a mixed culture medium solution. The mixed culture medium solution was diluted using the two-fold dilution method. MC3T3-E1 cells were plated at 5 × 10 cells per well. 3Cells were seeded into 96-well plates at a density of 100 μL per well, with three replicates. After the cells adhered, the culture medium was aspirated and 100 μL of gradient extract solution was added to each well. After incubation at 37°C for 1 and 3 days, 10 μL of MTT solution was added to each well. After incubation at 37°C for 4 hours, the extract was aspirated and 100 μL of DMSO solution was added to each well, mixed thoroughly, and the OD value of each well was measured at a wavelength of 490 nm on a microplate reader, and the relative proliferation rate of the cells in each well was calculated.

[0054] Example 1

[0055] The first step is to prepare a block polymer. 5g of acrylamide, 0.5g of 2-(dodecyl trithiocarbonate)-2-methylpropionic acid, and 0.03g of azobisisobutyronitrile are dissolved in 20mL of dimethyl sulfoxide, added to a 50mL Shrek bottle, completely frozen with liquid nitrogen, vacuumed for 10 minutes using a vacuum pump, then nitrogen is introduced for 10 minutes, and the bottle mouth is tightened to keep it closed. Place in an oil bath pot at 75°C with magnetic stirring and react for 9 hours. Then place in ice water to cool and interrupt the reaction, then precipitate the reaction solution in anhydrous ethanol, filter the precipitate with a suction flask and dry it to obtain a polyacrylamide segment. Then, 2.5g of the above-mentioned polyacrylamide segment, 2.5g of N-(3-aminopropyl) methacrylamide and 0.5g of 2-(dodecyl trithiocarbonate)-2-methylpropionic acid, and 0.01g of azobisisobutyronitrile were dissolved in 20mL of dimethyl sulfoxide, added to a 50mL Shrek bottle, completely frozen with liquid nitrogen, vacuumed for 10 minutes using a vacuum pump, then nitrogen was introduced for 10 minutes, and the bottle mouth was tightened to keep it closed. Placed in an oil bath pot with magnetic stirring at 75°C, reacted for 15 hours, then placed in ice water to cool and interrupt the reaction, and then the reaction solution was precipitated in anhydrous ethanol, filtered and precipitated with a suction flask and dried to obtain a polyacrylamide block polymer. The structural expression of the polyacrylamide segment (PAM-R) is formula (III), and the structural expression of the polyacrylamide block polymer (PbP) is formula (IV):

[0056]

[0057] Where m is a positive integer,

[0058]

[0059] Wherein, n is a positive integer;

[0060] In the second step, polyacrylamide grafted diethylenetriamine pentaacetic acid was prepared by dissolving 1.5 g of diethylenetriamine pentaacetic acid in 15 mL of deionized water, adjusting the pH to 6 using 0.1 mol / L sodium hydroxide, adding 0.1 g of polyacrylamide block polymer, adding 1.5 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide after 15 minutes, and then adding 0.5 g of N-hydroxysuccinimide after another 15 minutes. The mixture was stirred and reacted at room temperature for 24 hours, dialyzed against deionized water at 37° C. for 2 days, and freeze-dried in a freeze dryer to obtain the product polyacrylamide block polymer grafted diethylenetriamine pentaacetic acid (bifunctional polymer), wherein the structural expression of the polyacrylamide block polymer grafted diethylenetriamine pentaacetic acid (PPD) is formula (V):

[0061]

[0062] The third step was to prepare a bifunctional polymer-stabilized calcium phosphate precursor nanomaterial. 1g of polyacrylamide-block polymer grafted with diethylenetriaminepentaacetic acid was dissolved in 2mL of deionized water. After complete dissolution, 10mL of 0.05mol / L Na2HPO4 solution was added, stirred evenly, and the pH was adjusted to 8 to obtain Solution A. 10mL of 0.05mol / L CaCl2 solution was slowly added to Solution A with continuous stirring, and the pH was adjusted to 7.4. The solution remained clear and transparent. The calcium phosphate precursor material was formed in the polymer solution, resulting in the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial DCAP.

[0063] The bifunctional polymer-stabilized calcium phosphate precursor nanomaterial prepared by the above method has the following properties:

[0064] By H NMR spectroscopy (such as Figure 1 (shown), δ values ​​of 2.10 ppm and 1.51 ppm correspond to -CH2 and -CH- on the polymer backbone, respectively. The polyacrylamide segment was successfully prepared. δ values ​​of 2.92 ppm and 3.10 ppm correspond to -CH2 on N-(3-aminopropyl)methacrylamide, respectively, demonstrating the successful preparation of a block polymer with the introduction of the N-(3-aminopropyl)methacrylamide segment. The subsequent successful introduction of grafted diethylenetriaminepentaacetic acid demonstrated this phenomenon with δ values ​​of 3.50 ppm, 3.72 ppm, and 393 ppm, corresponding to positions within the DTPA structure.

[0065] The chelation capacity of polymers for calcium ions was characterized by chrome black T complexometric titration (e.g. Figure 2 As shown in the figure, the calcium ion chelating ability of the material increased from 2.3 mg / g to 15.2 mg / g, indicating that the introduction of the calcium chelator improved the polymer's calcium ion chelating ability and increased its stability to calcium phosphate precursors, and was significantly better than the same type of polymer polyaspartic acid (PASP).

[0066] The morphology, particle size and 3-day stability of the bifunctional polymer-stabilized calcium phosphate precursor nanomaterials were observed by transmission electron microscopy. Figure 3 As shown in the figure, the minimum particle size of the newly prepared material can reach about 50 nm. As time goes by, it gradually transforms into crystals in 3 days, which shows the mineralization ability of the material.

[0067] The mineralization ability of the materials on collagen fibers was characterized by transmission electron microscopy (e.g. Figure 4 (As shown), CAP is a pure calcium phosphate solution, and the RCAP and BCAP materials are monofunctional polymers, i.e., polymers without a grafted calcium chelator (PAM-R, PbP), to prepare calcium phosphate precursor nanomaterials. The results show that materials containing calcium chelators can better stabilize calcium phosphate precursors, allowing them to enter and mineralize within collagen fibers, achieving organic-inorganic composites. Polymers containing only a single function, however, have poor stabilization effects on calcium phosphate precursors, resulting in their only attachment to the collagen fiber surface and inability to fully mineralize.

[0068] By fluorescence staining, two-photon fluorescence microscopy (such as Figure 5 As shown in the figure, it can be observed that the material enters the collagen fibers and mineralizes, and the mineralization intensity is high.

[0069] The materials were tested for cytocompatibility by MTT toxicity test. Figure 6 The cell viability of the materials was above 80%, indicating that the materials had no cytotoxicity.

[0070] Alkaline phosphatase staining test was performed on the cells co-cultured with the materials to prove the osteogenic properties of the materials (such as Figure 7 The material group showed a significant increase in the blue staining area, demonstrating the material's osteogenic ability.

[0071] Example 2

[0072] First, a hydrogel solution was prepared by taking 0.2 g of modified collagen, 2 g of acrylamide, 0.05 g of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, and 0.05 g of N,N′-bis(acryloyl)cystamine and dissolving them in 10 mL of deionized water to obtain a hydrogel solution. The hydrogel solution was evenly coated on the surface of poly(phenylene ether sulfone ketone) (PPESK) material and cured under UV light for 3 min to obtain a collagen hydrogel coating modified PPESK.

[0073] Subsequently, the collagen hydrogel coating modified PPESK material was immersed in a bifunctional polymer-stabilized calcium phosphate precursor nanomaterial and mineralized at 37°C for 7 days to obtain a mineralized coating modified PPESK material.

[0074] The mineralized coating modified hydrogel material prepared by the above method has the following properties:

[0075] The thickness of the coating material can be observed by scanning electron microscopy (e.g. Figure 8 The thickness of the coating can be adjusted according to the amount of solution applied, and can reach 20 to 100 μm.

[0076] Through scanning electron microscopy and energy spectrum analysis, the mineralization degree and mineralization effect of the coating material can be observed (such as Figure 9 As shown in the figure, the coating is fully mineralized and the entire coating is evenly coated with calcium and phosphorus elements, indicating the preparation of the mineralized coating modified PPESK material.

Claims

1. A bifunctional polymer-stabilized calcium phosphate precursor nanomaterial, characterized in that: The concentration contains the following ingredients: bifunctional polymer concentration is 0.05~0.2g / mL; PO4 3- The concentration is 0.05~0.5mol / L; Ca 2+ The concentration is 0.05-0.5 mol / L, the solvent is deionized water, and the diameter of the calcium phosphate precursor nanomaterial is 20-100 nm. The bifunctional polymer structure is expressed as formula (I): Wherein, m and n are positive integers, and R1 is the main structure of the block polymer, which is one of the following structures: R2 is the main structure of the calcium chelator, which is one of the following structures:

2. A method for preparing a calcium phosphate precursor nanomaterial stabilized by a bifunctional polymer according to claim 1, characterized in that: The method comprises the following steps: dissolving 0.1-0.4 g of a bifunctional polymer in deionized water, adding 5-10 mL of a 0.1-1.0 mol / L Na2HPO4 solution after the solution is fully dissolved, stirring evenly, and adjusting the pH value to 6-8 to obtain a solution A; slowly adding 5-10 mL of a 0.1-1.0 mol / L CaCl2 solution to the solution A, continuously stirring, and adjusting the pH value to 7.4, wherein the solution always remains clear and transparent, and the calcium phosphate precursor nanomaterial is formed in the bifunctional polymer solution.

3. The method for preparing a calcium phosphate precursor nanomaterial that is stable with a bifunctional polymer as claimed in claim 2, wherein: The preparation method of the bifunctional polymer comprises the following steps: S1 uses free radical polymerization to prepare polyacrylamide block polymers: acrylamide, an initiator, a chain transfer agent and a solvent are mixed and polymerized to obtain polyacrylamide segments; then acrylamide monomers, the polyacrylamide segments, an initiator, a chain transfer agent and a solvent are mixed and polymerized to obtain polyacrylamide block polymers, which are expressed as formula (II): S2 polyacrylamide block polymer grafted with calcium chelating agent: using 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to activate the amino group of the polyacrylamide block polymer, followed by amidation reaction, and grafting the calcium chelating agent to obtain the bifunctional polymer; The acrylamide monomer in S1 is N-(3-aminopropyl)methacrylamide, N-(3-aminophenyl)acrylamide, N-(2-aminoethyl)acrylamide or N-(2-aminoethyl)methacrylamide; and the calcium chelating agent in S2 is diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid or ethylene glycol bis(2-aminoethyl ether)tetraacetic acid.

4. The method for preparing a calcium phosphate precursor nanomaterial that is stable with a bifunctional polymer as claimed in claim 3, wherein: In S1, the initiator is azobisisobutyronitrile, the chain transfer agent is 2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and the solvent is dimethyl sulfoxide.

5. The method for preparing a calcium phosphate precursor nanomaterial stabilized by a bifunctional polymer as claimed in claim 3, wherein: The polymerization time of the polyacrylamide segment in S1 is 9 to 12 hours, the polymerization time of the polyacrylamide block polymer is 9 to 16 hours, and the molar ratio of the chain transfer agent to the initiator is 5 to 10.

6. Use of the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial according to claim 1 in collagen fiber mineralization.

7. A mineralized coating modified PPESK material, characterized by: The invention comprises a PPESK material modified by a hydrogel coating, wherein the coating uniformly covers calcium and phosphorus elements.

8. A method for preparing the mineralized coating modified PPESK material according to claim 7, characterized in that: The surface of the PPESK coating is modified, comprising performing a mineralization modification treatment on the hydrogel coating-modified PPESK material using the bifunctional polymer-stabilized calcium phosphate precursor nanomaterial according to claim 1 to obtain a mineralized coating-modified PPESK material.

9. The method for preparing the mineralized coating modified PPESK material according to claim 8, characterized in that: The hydrogel coating modified PPESK material is obtained by coating a hydrogel solution on the surface of the PPESK material and curing it with ultraviolet light; the hydrogel solution is obtained by dissolving hydrogel coating raw materials, a photoinitiator and a crosslinking agent in deionized water.

10. The method for preparing the mineralized coating modified PPESK material according to claim 8, characterized in that: The mineralization temperature is 25-40°C and the mineralization time is 7-14 days.

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