A polyetheretherketone-silicon nitride composite nanobiological coating and its preparation process

Abstract

The present invention belongs to the technical field of orthopedic and dental implant materials, and particularly relates to a polyetheretherketone-silicon nitride composite nano-bioactive coating and a preparation process thereof, comprising the following steps: dissolving chitosan in an acetic acid solution to prepare a chitosan acetic acid solution, then adding polyetheretherketone into the chitosan acetic acid solution, and after defoaming, preparing a slurry; spin-coating or spraying the slurry on the surface of a substrate, and after drying, performing sintering treatment to obtain a porous polyetheretherketone coating; using a magnetron sputtering technique to prepare a Si3N4 coating on the porous polyetheretherketone coating to obtain the polyetheretherketone-silicon nitride composite nano-bioactive coating. The finally obtained coating of the present invention not only has a fine nano-structure, but also has good effects in terms of mechanical properties and biological properties.

Description

Technical Field

[0001] The invention belongs to the technical field of orthopedic and dental implant materials, and particularly relates to a polyetheretherketone-silicon nitride composite nano bio-coating and a preparation process thereof. Background Art

[0002] Polyetheretherketone (PEEK) is a semi-crystalline, thermoplastic special engineering plastic with excellent mechanical properties, biocompatibility, corrosion resistance, easy processing and molding, and radiation penetration. These outstanding advantages make PEEK increasingly used as bone / dental implant materials. However, due to the hydrophobicity and biological inertness of PEEK materials, PEEK often exhibits poor bonding with surrounding bone tissue when implanted as a bone substitute. To solve this problem, there are usually two solutions. One is to introduce excellent bioactive materials into PEEK to make a composite material; the other is to modify the surface of PEEK to obtain a surface nano-morphology, enhance the surface hydrophilicity and bioactivity, and thus enhance the bonding between PEEK and bone tissue.

[0003] Studies have shown that porous PEEK can improve bone integration more effectively than smooth PEEK. To solve the poor bone integration defects caused by the hydrophobicity and biological inertness of PEEK materials, a Chinese patent with publication number CN114146218A discloses an artificial bone made of porous PEEK material and its preparation method. PEEK artificial bone with integrally connected porous joints is prepared by 3D printing, and the bioactive coating is evenly coated on the inner and outer surfaces of the porous material by wet chemical method. The final material has both mechanical support and biological functions of bone induction and bone integration. Silicon nitride has good bone conductivity, biocompatibility and antibacterial properties, and is also a very promising orthopedic medical material. Zhiyan Xu et al. (J. Mater. Chem. B, 2019, 7, 6035) used inductively coupled plasma enhanced chemical vapor deposition (ICPECVD) technology to coat the PEEK surface with Si3N4. The coating surface showed a layered nanostructure, which contained many nanoscale spherical protrusions, had good antibacterial activity and cell compatibility, and could significantly promote the adhesion, proliferation, differentiation and expression of osteogenesis-related genes of rat bone marrow stromal cells (rBMSCs). In recent years, a variety of preparation processes have been adopted at home and abroad to modify the physical and chemical properties of the PEEK surface, such as direct treatment of the PEEK material surface with plasma, laser, etc., or compounding bioactive materials such as hydroxyapatite with PEEK materials, or coating the PEEK surface with a hydrophilic bioactive coating. These methods can more or less enhance the osteogenic activity, antibacterial activity or bone integration ability.

[0004] On the whole, among the many measures currently used to treat poor bone integration of PEEK materials, 3D printing, direct physical treatment of the surface, physical deposition of the surface, and wet chemical modification are the most widely used. Although 3D printing technology can produce more complex components, its printing accuracy can only be controlled at the micron level, and it is not possible to print more sophisticated nanostructures. If you want to obtain nanoscale microstructures on the PEEK surface, 3D printing is obviously not suitable. Physical treatments such as surface patterning are mainly aimed at causing changes in the surface morphology and roughness of PEEK materials, but simply changing the surface roughness to improve the bone integration ability of PEEK materials is often limited. Surface deposition can generally improve bone integration, but it cannot handle implants with complex shapes. Although the wet chemical modification method can meet the processing requirements of complex implants, the long-term storage stability and sterilization resistance of the material need to be further explored, and it often results in reagent waste and is not environmentally friendly. Summary of the invention

[0005] The present invention provides a polyetheretherketone-silicon nitride composite nano bio-coating and a preparation process thereof. A porous PEEK and Si3N4 combined nano-coating is prepared by taking titanium alloy as a substrate and combining spin coating / spraying, sintering and magnetron sputtering. The prepared PEEK coating fiber has a porous structure, which enhances the bonding strength between cells and the coating. The silicon nitride layer improves the hydrophilicity of the coating, which plays a positive role in cell adhesion, proliferation and differentiation.

[0006] The present invention is specifically achieved through the following technical solutions.

[0007] The first object of the present invention is to provide a preparation process of a polyetheretherketone-silicon nitride composite nano bio-coating, comprising the following steps:

[0008] Dissolving chitosan in an acetic acid aqueous solution to prepare a chitosan acetic acid aqueous solution, then adding polyetheretherketone to the chitosan acetic acid aqueous solution, and degassing to prepare a slurry;

[0009] The slurry is spin-coated or spray-coated on the surface of the substrate, and after drying, a sintering treatment is performed to remove chitosan and water to obtain a porous polyetheretherketone coating;

[0010] The magnetron sputtering technology is adopted to prepare a nano Si3N4 coating with a thickness between 250nm and 3800nm ​​on the porous polyetheretherketone coating to obtain the polyetheretherketone-silicon nitride composite nano biological coating.

[0011] In a preferred embodiment of the present invention, the sintering treatment conditions are: heating from room temperature to 350-450°C at a rate of 1-50°C / min, keeping the temperature for 5-60 minutes, and then cooling with the furnace.

[0012] In a preferred embodiment of the present invention, when magnetron sputtering Si3N4 coating, the substrate is fixed at a position 160mm away from the Si target, and then vacuumed for 20 minutes, the workbench speed is set to 15r / min, and the substrate is cleaned for 40 minutes under the conditions of bias 300V and duty cycle 72.0, and finally the Ar flow rate is set to 20-60sccm and the N2 flow rate is 10-30sccm, and the product is sputtered for 0.5-4h at a 100W RF power supply.

[0013] In a preferred embodiment of the present invention, before magnetron sputtering the Si3N4 coating, the chamber is first evacuated, and then the Si target is cleaned, and the Ar flow rate is set to 50 sccm and the working pressure is 2 Pa.

[0014] In a preferred embodiment of the present invention, the mass volume ratio of polyetheretherketone to acetic acid solution is 1-7g:20mL. If the polyetheretherketone content is too high, on the one hand, the polyetheretherketone film will be too thick and easy to peel off from the substrate; on the other hand, the aggregation density of polyetheretherketone is too high, and the polyetheretherketone will be interconnected and spread when melted, and the porosity will decrease after recrystallization, and an ideal porous structure cannot be formed.

[0015] In a preferred embodiment of the present invention, the concentration of the acetic acid solution is 0.1-2 mol / L, and the ratio of chitosan to acetic acid solution is 0.1-0.4 g: 10 mL. If the amount of chitosan is too little, the sol is not viscous enough, the sol cannot stay on the surface of the substrate, and will fly away from the substrate under the action of centrifugal force during the spin coating process; if the amount of chitosan is too much, the sol is too viscous, which will lead to uneven spin coating and poor film quality.

[0016] In a preferred embodiment of the present invention, when the slurry is spin-coated, the rotation speed is 1000-2500 r / min and the acceleration is 100-500 r / s 2 Spin coating for 10-60s at setting.

[0017] In a preferred embodiment of the present invention, the substrate is first pretreated, specifically, the substrate surface is polished in turn with 240 mesh, 600 mesh, and 1000 mesh sandpaper to remove surface oxides and impurities, and then cleaned to remove surface water stains.

[0018] The second object of the present invention is to provide a polyetheretherketone-silicon nitride composite nano-bio-coating prepared by the above-mentioned preparation method, wherein a polyetheretherketone coating and a nano-Si3N4 coating are sequentially arranged on a substrate, and the surface of the polyetheretherketone coating is a fiber structure, and nanopores are distributed on the fiber structure.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses titanium alloy (TC4) as a substrate and combines spin coating / spraying, sintering, and magnetron sputtering to prepare a layered nano coating of porous PEEK and Si3N4. The specific advantages are:

[0021] The surface of the PEEK coating prepared by spin coating and sintering presents a fibrous structure with many nanopores distributed on the fibers. The presence of these pores provides more attachment points for cells, which is beneficial for cell adhesion and allows cells to penetrate into the coating. Mechanical interlocking is formed between the coating and the cells, thereby enhancing the bonding strength between the cells and the coating and facilitating the fixation of the implant.

[0022] A layer of Si3N4 was deposited on the porous surface of PEEK by magnetron sputtering, and the thickness was precisely controlled at the nanometer level. While retaining the nanostructure of the PEEK surface, the hydrophilic groups on the surface of the Si3N4 layer can significantly improve the hydrophilicity of the composite coating, which is beneficial to the interaction between the coating and the protein layer on the cell surface, and plays a positive role in cell adhesion, proliferation, and differentiation. In addition, due to the deposition of the Si3N4 layer, the mechanical properties of the final coating, such as hardness and Young's modulus, will be improved.

[0023] The coating finally obtained by the present invention not only has a fine nanostructure, but also has good effects on mechanical properties and biological properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A process flow chart of the preparation of the polyetheretherketone (PEEK)-silicon nitride composite nano-bio-coating provided by the present invention;

[0025] Figure 2 is the sintering temperature curve of PEEK coating;

[0026] Figure 3 The cross-section and surface scanning electron microscope images of PEEK-silicon nitride composite coatings, where (1) and (2) are the cross-section and surface of PEEK-4, respectively; (3) and (4) are the cross-section and surface of PEEK-4-SN-3h, respectively; (5) and (6) are EDS element distribution diagrams of PEEK-4-SN-3h, where red dots represent Si and green dots represent N;

[0027] Figure 4 is the XRD diffraction pattern of sample PEEK-4-SN-3h;

[0028] Figure 5 Atomic force microscopy is used to characterize the surface roughness and porous structure and Young's modulus of PEEK-silicon nitride composite coatings. (1) and (2) are the surface morphology and three-dimensional modulus diagrams of PEEK-4, respectively; (3) and (4) are the surface morphology and three-dimensional modulus diagrams of PEEK-4-SN-3h, respectively;

[0029] Figure 6 The water contact angle test results of the blank Ti sheet and the PEEK coating before and after sputtering for 1 hour. The orange column represents the pure PEEK coating before magnetron sputtering; the green column represents the PEEK-silicon nitride composite coating after magnetron sputtering;

[0030] Figure 7 The surface SEM scan images of MC3T3-E1 cells inoculated on blank Ti (1), PEEK-1 (2), PEEK-4 (3), PEEK-7 (4), PEEK-1-SN-1h (5), PEEK-4-SN-1h (6), and PEEK-7-SN-1h (7) after culturing for 1 day;

[0031] Figure 8 The immunofluorescence staining images of cells were assembled after 1 day of cell culture, using FITC-phalloidin to stain F-actin and DAPI to stain cell nuclei, including blank Ti (1), PEEK-1 (2), PEEK-4 (3), PEEK-7 (4), PEEK-1-SN-1h (5), PEEK-4-SN-1h (6), PEEK-7-SN-1h (7);

[0032] Fig. 9 The representative fluorescence photos are after the cell nuclei were stained with DAPI for 10 min after 4 h of cell culture, including blank Ti (1), PEEK-1 (2), PEEK-4 (3), PEEK-7 (4), PEEK-1-SN-1h (5), PEEK-4-SN-1h (6), and PEEK-7-SN-1h (7);

[0033] Fig.10 In the figure, (1) and (2) are the quantitative results of cell adhesion of the coating before and after modification by magnetron sputtering silicon nitride, respectively; (3) is the CCK8 absorbance measurement result of cell proliferation after 3 days of culture on the coating modified by magnetron sputtering silicon nitride. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0035] The present invention provides a preparation process of polyetheretherketone-silicon nitride composite nano bio-coating, such as Figure 1 As shown, the following steps are included:

[0036] The chitosan acetate aqueous solution and polyetheretherketone are mixed to prepare a slurry.

[0037] The slurry is spin-coated or spray-coated on the surface of the substrate, and sintered to remove chitosan and water to obtain a porous polyetheretherketone coating; the surface of the PEEK coating prepared by spin coating or spraying and sintering presents a fiber structure, and many nanopores are distributed on the fibers. The presence of these pores provides more attachment points for cells, which is beneficial to cell adhesion, allowing cells to penetrate into the coating, forming a mechanical interlock between the coating and the cells, thereby enhancing the bonding strength between the cells and the coating, which is beneficial to the fixation of the implant.

[0038] A nano-Si3N4 coating is prepared on the porous polyetheretherketone coating by magnetron sputtering technology to improve the hydrophilicity of the coating, thereby obtaining the polyetheretherketone-silicon nitride composite nano-biocoating. A layer of Si3N4 is deposited on the porous surface of PEEK by magnetron sputtering, and the thickness is precisely controlled at the nanometer level. While retaining the nanostructure of the PEEK surface, the hydrophilic groups on the surface of the Si3N4 layer can significantly improve the hydrophilicity of the composite coating, which is beneficial to the interaction between the coating and the protein layer on the cell surface, and plays a positive role in cell adhesion, proliferation, and differentiation. In addition, due to the deposition of the Si3N4 layer, the mechanical properties of the final coating, such as hardness and Young's modulus, will be improved.

[0039] The present invention will be specifically described below through the following examples and comparative examples.

[0040] Example 1

[0041] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0042] (1) Preparation of slurry: 0.4 g chitosan powder was immersed in 20 mL 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 1 g PEEK (polyetheretherketone) powder was added thereto and mixed thoroughly by mechanical stirring. Then, a Japanese THINKYAR-100 mixer and degasser was used to rotate at 1500 r / min for 120 s to remove air from the reagent and make the PEEK particles disperse more evenly. The obtained slurry was recorded as slurry-1.

[0043] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0044] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0045] (3) Sintering, such as Figure 2 As shown: Use KSL-1700X high temperature box furnace. After the substrate after spin coating is naturally air-dried, follow Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-1.

[0046] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the PEEK-1 sample on a small steel plate, and keep it at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the chamber for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the sample for 1 hour under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-1-SN-1h.

[0047] Example 2

[0048] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0049] (1) Preparation of slurry: 0.4 g chitosan powder was immersed in 20 mL 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 4 g PEEK powder was then added thereto and mixed thoroughly by mechanical stirring. A Japanese THINKYAR-100 mixer degasser was then used to rotate at 1500 r / min for 120 s to remove air from the reagent and also to make the PEEK particles more evenly dispersed. The obtained slurry was recorded as slurry-4.

[0050] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0051] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0052] (3) Sintering: Use KSL-1700X high temperature box furnace. After the substrate is naturally air-dried after spin coating, Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-4.

[0053] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the PEEK-4 sample on a small steel plate, and keep it at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the chamber for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the samples uniformly for 1 hour under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-4-SN-1h.

[0054] Example 3

[0055] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0056] (1) Preparation of slurry: 0.4 g chitosan powder was immersed in 20 mL 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 7 g PEEK powder was added thereto and mixed thoroughly by mechanical stirring. Then, a Japanese THINKYAR-100 mixer degasser was used to rotate at 1500 r / min for 120 s to remove air from the reagent and make the PEEK particles more evenly dispersed. The obtained slurry was recorded as slurry-7.

[0057] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0058] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0059] (3) Sintering: Use KSL-1700X high temperature box furnace. After the substrate is naturally air-dried after spin coating, Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-7.

[0060] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the PEEK-7 sample on a small steel plate, and keep it at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the chamber for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the samples uniformly for 1 hour under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-7-SN-1h.

[0061] Example 4

[0062] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0063] (1) Preparation of slurry: 0.4 g chitosan powder was immersed in 20 mL 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 1 g PEEK powder was then added thereto and mixed thoroughly by mechanical stirring. A Japanese THINKYAR-100 mixer degasser was then used to rotate at 1500 r / min for 120 s to remove air from the reagent and also to make the PEEK particles more evenly dispersed. The obtained slurry was recorded as slurry-1.

[0064] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0065] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0066] (3) Sintering: Use KSL-1700X high temperature box furnace. After the substrate is naturally air-dried after spin coating, Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-1.

[0067] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the PEEK-1 sample on a small steel plate, and keep it at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the vacuum for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the samples uniformly for 3 hours under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-1-SN-3h.

[0068] Example 5

[0069] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0070] (1) Preparation of slurry: 0.4 g of chitosan powder was immersed in 20 mL of 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 4 g of PEEK powder was then added thereto and mixed thoroughly by mechanical stirring. A Japanese THINKYAR-100 mixer degasser was then used to rotate at 1500 r / min for 120 s to remove air from the reagent and also to make the PEEK particles more evenly dispersed. The obtained slurries were respectively recorded as slurry-4.

[0071] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0072] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0073] (3) Sintering: Use KSL-1700X high temperature box furnace. After the substrate is naturally air-dried after spin coating, Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-4.

[0074] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the PEEK-4 sample on a small steel plate, and keep it at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the chamber for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the samples uniformly for 3 hours under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-4-SN-3h.

[0075] Example 6

[0076] A porous nano coating composed of PEEK and Si3N4 includes two layers of coating, an upper layer and a lower layer. The preparation process of the coating includes the following steps:

[0077] (1) Preparation of slurry: 0.4 g chitosan powder was immersed in 20 mL 0.5 mol / L acetic acid aqueous solution to increase the solution viscosity; 7 g PEEK powder was then added thereto and mixed thoroughly by mechanical stirring. A Japanese THINKYAR-100 mixer degasser was then used to rotate at 1500 r / min for 120 s to remove air from the reagent and also to make the PEEK particles more evenly dispersed. The obtained slurries were respectively recorded as slurry-7.

[0078] (2) Substrate pretreatment: TC4 alloy was selected, and a disc with a specification of 10 mm × 10 mm × 2 mm was used as the substrate. The substrate surface was polished with sandpapers of 240 mesh, 600 mesh, and 1000 mesh in turn to remove surface oxides and impurities, and then ultrasonic cleaning was performed. Finally, dust-free paper was used to remove surface water stains.

[0079] Spin coating: Use EZ4-S-PP small coating machine. Prepare the slurry in step (1), fix the substrate with a vacuum pump, use a rubber dropper to absorb an appropriate amount of slurry and drop it on the surface of the substrate, set the spin coater to a speed of 2500r / min and an acceleration of 500r / s 2 Spin coating for 30 s at 40 °C. This is the first step to obtain pure PEEK coating.

[0080] (3) Sintering: Use KSL-1700X high temperature box furnace. After the substrate is naturally air-dried after spin coating, Figure 2 The sintering curve shown sets the relevant parameters of the sintering furnace, puts it into the furnace for sintering, heats from room temperature to 350℃ at a rate of 10℃ / min, keeps warm for 30min, and then cools with the furnace to obtain the first layer of porous PEEK coating after melting and recrystallization. The pure PEEK coating corresponding to the slurry is recorded as PEEK-7.

[0081] (4) Magnetron sputtering: Use a PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix four PEEK-7 samples on a small steel plate, and keep them at 60°C for 20 minutes to dry the solid glue. Perform magnetron sputtering at room temperature: first, evacuate the chamber for 20 minutes, then clean the Si target, set the Ar flow rate to 50sccm, and the working pressure to 2Pa, which is equivalent to substrate-free magnetron sputtering. Perform plasma cleaning on the Si surface for 30 minutes to remove oxides, dust and other impurities on the Si target surface. After cleaning, fix the substrate at a distance of 160mm from the Si target, evacuate the chamber for another 20 minutes, set the workbench speed to 15r / min, and clean the substrate for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, set the Ar flow rate to 40sccm and the N2 flow rate to 20sccm. Sputter the sample for 3 hours under a 100W RF power supply to obtain a nano-Si3N4 coating. Finally, a PEEK / Si3N4 double-layer nanocoating was obtained, which was recorded as PEEK-7-SN-3h.

[0082] Comparative Example 1

[0083] Magnetron sputtering: Use PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the pure Ti alloy substrate sample on a small steel plate, and keep it at 60℃ for 20 minutes to dry the solid glue. Magnetron sputtering is performed at room temperature: first, the chamber is evacuated for 20 minutes, then the Si target is cleaned, the Ar flow rate is set to 50sccm, and the working pressure is 2Pa, which is equivalent to substrate-free magnetron sputtering. The Si surface is plasma cleaned for 30 minutes to remove oxides, dust and other impurities on the surface of the Si target. After cleaning, the substrate is fixed at a position 160mm away from the Si target, and then evacuated for 20 minutes. The workbench speed is set to 15r / min. The substrate is cleaned for 40 minutes under the conditions of bias voltage 300V and duty cycle 72.0. Finally, the Ar flow rate is set to 40sccm and the N2 flow rate is 20sccm. The samples are uniformly sputtered for 1h under a 100W RF power supply to obtain a nano-Si3N4 coating recorded as SN-1h.

[0084] Comparative Example 2

[0085] Magnetron sputtering: Use PD-600 multi-arc magnetron multifunctional coating machine. Use solid glue to fix the pure Ti alloy substrate sample on a small steel plate, and keep it at 60℃ for 20min to dry the solid glue. Magnetron sputtering is performed at room temperature: first, the chamber is evacuated for 20min, then the Si target is cleaned, the Ar flow rate is set to 50sccm, and the working pressure is 2Pa, which is equivalent to substrate-free magnetron sputtering. The Si surface is plasma cleaned for 30min to remove oxides, dust and other impurities on the surface of the Si target. After cleaning, the substrate is fixed at a position 160mm away from the Si target, and then evacuated for 20min, the workbench speed is set to 15r / min, and the substrate is cleaned for 40min under the conditions of bias 300V and duty cycle 72.0. Finally, the Ar flow rate is set to 40sccm and the N2 flow rate is 20sccm. The samples are uniformly sputtered for 3h under a 100W RF power supply to obtain a nano-Si3N4 coating recorded as SN-3h.

[0086] The nano-Si3N4 coating obtained by sputtering for 1 hour is relatively thin, which is to enhance the hydrophilicity of the coating while retaining the nanostructure of the PEEK surface, both of which are conducive to cell adhesion. The Si3N4 coating obtained by sputtering for 3 hours is relatively thick, which is convenient for observing the surface morphology and analyzing the phase of the coating. Generally, the elastic modulus of Si3N4 in an amorphous state is between 10 and 20 GPa. In this way, the Si3N4 layer can play a greater role in the mechanical property test, which is of great help to improve the overall mechanical properties of the coating.

[0087] Experimental methods:

[0088] 1. Microstructure characterization experiment of coating

[0089] (1) X-ray diffraction (XRD) spectrum test

[0090] The samples were scanned by X-ray diffraction (XRD-7000, copper source).

[0091] (2) Scanning electron microscope (SEM) test

[0092] The microscopic morphology of the surface or fracture of the sample was observed by a scanning electron microscope (FSEM, JSM-7600F), and the elemental composition of the PEEK-4-SN coating was analyzed by a high-performance X-ray energy dispersive spectrometer (EDS), an accessory of the electron microscope, to explore the ratio of Si and N elements.

[0093] (3) Atomic force microscopy (AFM) testing

[0094] The physical properties of the coating in the nano region were detected by atomic force microscopy (AFM, Jupiter XR). Figure 5 Atomic force microscopy was used to characterize the rough surface porous structure and Young's modulus of PEEK / silicon nitride composite coatings. (1) and (2) are the surface morphology and three-dimensional modulus diagrams of PEEK-4, respectively; (3) and (4) are the surface morphology and three-dimensional modulus diagrams of PEEK-4-SN-3h, respectively.

[0095] (II) Hydrophilicity test

[0096] The water contact angle of the samples was measured by a contact angle meter (CAT, KRUSSDSA100) to compare the hydrophilic properties of the coatings. To ensure the accuracy of the results, the experiment was repeated three times for each sample. Figure 6 These are the water contact angle test results of the blank Ti sheet and the PEEK coating before and after sputtering for 1 hour. The orange column represents the pure PEEK coating before magnetron sputtering; the green column represents the PEEK / silicon nitride composite coating after magnetron sputtering.

[0097] (III) Osteoblast response experiment

[0098] (1) Cell culture

[0099] Mouse embryonic osteoblast precursor cells (MC3T3-E1, OB, Catalog number: GNM15) were selected, the cells were revived, and an appropriate amount of complete culture medium (α-MEM culture medium containing 10% fetal bovine serum and 1% penicillin / streptomycin) was added to the cryopreservation tube. After centrifugation, the supernatant was discarded, and an appropriate amount of culture medium was added according to the cell volume to resuspend the cells and count them. After culturing for 24 hours at 37°C, 5% CO2 concentration, and 95% air concentration, the culture medium was removed and the cells were rinsed with PBS solution. After reaching a near-confluent state, the cells were separated using 0.25% trypsin (Beyotime, China), and the cell clusters were revived and resuspended and counted using complete culture medium at room temperature. The culture medium was replaced every two days. Unless otherwise specified, the cell seeding density was 2×10 4 cells / cm 2 The culture medium was changed every two days after cell seeding.

[0100] (2) Cell morphology observation

[0101] The cells were cultured at 1×10 4 cells / cm 2The density of the plating was inoculated in 24 wells containing samples (blank Ti, PEEK-1, PEEK-4, PEEK-7, PEEK-1-SN-1h, PEEK-4-SN-1h, PEEK-7-SN-1h), and each group of samples had two parallel samples. After culturing for 1 day at 37°C, 5% CO2, and 95% air concentration, the samples were washed three times with sterile PBS buffer solution to wash away cells with poor adhesion on the sample surface, and the samples were soaked in 2.5% glutaraldehyde solution to fix the cells. The cells were dried with alcohol in a stepwise manner (30%, 50%, 70%, 90%, 100%). Spray gold and observe the cell adhesion morphology under an electron microscope. Similarly, the 7 groups of samples (two parallel samples in each group) were stained with FITC-phalloidin for cytoskeleton and DAPI for nucleus after culturing for 1 day, assembled into cell immunofluorescence staining images, and the cell adhesion morphology was observed with the assistance of confocal laser scanning microscopy (CLSM). After 4 hours of culture, the cell nuclei were stained with DAPI for 10 minutes. Three fields of view were randomly selected for each sample and counted using ImageJ. The number of cell adhesion of the same sample before and after sputtering was compared to explore the effects of the properties of PEEK and the rough surface morphology on cells, and whether Si3N4 is conducive to cell adhesion and proliferation.

[0102] (3) Cell proliferation ability detection

[0103] The cells were cultured at 2 × 10 4 cells / cm 2 The cells were inoculated in 24-well plates containing samples (blank Ti, PEEK-1, PEEK-4, PEEK-7, PEEK-1-SN-1h, PEEK-4-SN-1h, PEEK-7-SN-1h) at a density of 10%. The cell growth state and density were observed under a microscope, and the wells with good growth state, uniform cell distribution and density were selected for the experiment. Six parallel samples were set up for each group of samples, and after 3 days at 37°C, 5% CO2, and 95% air concentration. A culture medium containing 10% CCK-8 solution was prepared, and then the cells were transferred to a new 24-well cell culture plate, cultured under the same environmental conditions for 2 hours, and the absorbance was measured at 450nm using an enzyme reader. The absorbance can reflect the proliferation activity of the cells.

[0104] The above experimental results are analyzed as follows:

[0105] (1) The spectrum obtained by scanning the sample PEEK-4-SN-3h by X-ray diffractometer is as follows: Figure 4 As shown, after comparing with the standard diffraction patterns of PEEK, silicon nitride and α-Ti, it is found that only the diffraction peaks of PEEK and α-Ti exist, which indicates that the sputtered silicon nitride is in an amorphous state.

[0106] (2) Observe the surface morphology and cross-sectional structure of each coating using a scanning electron microscope. Figure 3 The cross-section and surface scanning electron microscope images of PEEK / silicon nitride composite coatings, where (1) and (2) are the cross-section and surface of PEEK-4, respectively; (3) and (4) are the cross-section and surface of PEEK-4-SN-3h, respectively; (5) and (6) are EDS element distribution diagrams of PEEK-4-SN-3h: red dots represent Si, and green dots represent N). Figure 3 As shown, combined with the surface morphology characterized by AFM, Figure 5 As shown in the figure, after heating, melting, solidification and recrystallization, PEEK forms a fibrous structure with disorderly dispersed micron-sized holes. After magnification, many nano-sized holes can be seen. The sputtered silicon nitride is spread on the rough surface of the PEEK coating with a thickness of about 1 to 3 μm. The porous structure of the PEEK surface is relatively intact. The silicon nitride coating itself is composed of many nanoparticles. Figure 3 (5) and (6) are the EDS element distribution diagrams of PEEK-4-SN-3h. The red dots represent Si and the green dots represent N. The Si:N atomic ratio is about 4, and this ratio changes with the scanning area. This confirms that a layer of nitride silicon (SiN) is deposited by magnetron sputtering and is in an amorphous state.

[0107] (3) Figure 5 The Young's modulus and hardness of PEEK-4 and PEEK-4-SN-3h samples were obtained by AFM nanomechanical characterization. Figure 5 The three-dimensional modulus diagram in Figure 2 shows that the Young's modulus of the PEEK coating and the PEEK / SiN composite coating is mainly concentrated between 10 and 20 GPa, which is consistent with the modulus of PEEK and conventional amorphous nitrides. The figure shows that the modulus of the coating is very dependent on the surface morphology. In general, the mechanical properties of the coating are similar to those of cancellous bone, so it is more suitable as a bone implant in terms of matching mechanical properties.

[0108] (4) Figure 6 The water contact angle test results of the blank Ti sheet and the PEEK coating before and after sputtering for 1 hour. The orange column represents the pure PEEK coating before magnetron sputtering; the green column represents the PEEK-silicon nitride composite coating after magnetron sputtering. Figure 6As shown in the figure, it is found that the contact angles of the four coatings before sputtering are close to 90°, which indicates that both the Ti substrate and PEEK are hydrophobic. By comparing the water contact angles of the four samples after sputtering with the contact angles of the corresponding samples before sputtering, it can be found that the contact angles have all decreased significantly, which indicates that the silicide layer improves the hydrophilicity of the PEEK coating and creates favorable conditions for subsequent cell adhesion, proliferation, and differentiation. In addition, by comparing the water contact angles of the four samples after sputtering, it can be found that the contact angle increases with the increase of PEEK, which further confirms that the hydrophilicity of PEEK is poor.

[0109] The cell adhesion morphology was observed by SEM and CLSM. Figure 7 , Figure 8 , it can be observed that the cells adhere to the substrate by extending tentacles, and are flat and spread out. However, cells that fail to adhere or adhere poorly have almost no tentacles, and only the nucleus can be seen in the fluorescent photo, and the appearance is spherical. Figure 7 It is not difficult to see that before magnetron sputtering silicon nitride modification, with the increase of PEEK, the number of cells successfully attached became less and less, and the number of cells on the surface of PEEK-4 and PEEK-7 decreased significantly, which shows that PEEK is not conducive to cell adhesion. After magnetron sputtering silicon nitride modification, compared with the same concentration of PEEK before modification, the number of cells attached to the surface of the corresponding composite coating after modification increased significantly, which shows that the SiN layer is beneficial to enhance cell adhesion after enhancing the hydrophilicity of PEEK; and with the increase of PEEK, the number of cells successfully attached also increased significantly, which also confirms that the rough porous fiber structure of the PEEK surface provides more attachment points for cells, which can enhance cell adhesion. Fig.10 (1) and (2) are the ImageJ counts of cell adhesion of samples before and after magnetron sputtering silicon nitride modification 4 hours after inoculation. The trends in the two figures further confirm the above conclusions. Fig. 9 The following are representative fluorescence photos of cells stained with DAPI for 10 minutes after 4 hours of cell culture, including blank Ti (1), PEEK-1 (2), PEEK-4 (3), PEEK-7 (4), PEEK-1-SN-1h (5), PEEK-4-SN-1h (6), and PEEK-7-SN-1h (7).

[0110] (5) The cell proliferation ability was detected by CCK8 reagent. Because the cell adhesion effect was poor before magnetron sputtering silicon nitride modification, it can be predicted that the cell proliferation activity was average. Therefore, only the four samples of blank Ti, PEEK-1-SN-1h, PEEK-4-SN-1h, and PEEK-7-SN-1h were tested for absorbance. Fig.10In (3), the greater the absorbance, the stronger the cell proliferation activity. After magnetron sputtering silicon nitride modification, as the amount of PEEK increases, the absorbance also increases, indicating that under the combined effect of the porous structure of PEEK and the hydrophilic SiN layer, the cell proliferation ability is also significantly enhanced, which echoes the conclusion in the previous article. The above biological experiments preliminarily verified the excellent biological properties of the PEEK / SiN composite nanocoating.

[0111] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.

Claims

1. A preparation process of polyetheretherketone-silicon nitride composite nano bio-coating, characterized in that: The following steps are involved: The chitosan acetate aqueous solution and polyetheretherketone are mixed to prepare a slurry; Spin coating or spray coating the slurry on the surface of the substrate, and performing a sintering process to remove chitosan and water to obtain a porous polyetheretherketone coating; The surface of the polyetheretherketone coating is a fiber structure, and nanopores are distributed on the fiber structure; The nano-Si3N4 coating is prepared on the porous polyetheretherketone coating by magnetron sputtering technology to improve the hydrophilicity of the coating, thereby obtaining the polyetheretherketone-silicon nitride composite nano-biological coating; the thickness of the nano-Si3N4 coating is 250nm-3800nm.

2. The preparation process according to claim 1, characterized in that: When magnetron sputtering Si3N4 coating, a Si target is used, and sputtering is performed on the porous polyetheretherketone coating for 0.5-4h under a mixed atmosphere of Ar and N2 and a radio frequency power supply with a power of 100W, wherein the Ar flow rate is 20-60sccm and the N2 flow rate is 10-30sccm.

3. The preparation process according to claim 1, characterized in that: The sintering treatment conditions are: heating from room temperature to 350-450°C at a rate of 1-50°C / min, and keeping the temperature for 5-60 minutes.

4. The preparation process according to claim 1, characterized in that: Chitosan is dissolved in an acetic acid aqueous solution to obtain a chitosan acetic acid aqueous solution, the mass volume ratio of polyetheretherketone to the acetic acid aqueous solution is 1-7g:20mL, and the concentration of the acetic acid aqueous solution is 0.1-2mol / L.

5. The preparation process according to claim 4, characterized in that: The dosage ratio of chitosan and acetic acid aqueous solution is 0.1-0.4 g:10 mL.

6. The preparation process according to claim 1, characterized in that: When spin coating the slurry, the speed is 1000-2500r / min and the acceleration is 100-500r / s 2 Spin coating for 10-60s at setting.

7. The preparation process according to claim 1, characterized in that: Before magnetron sputtering Si3N4 coating, the chamber is first evacuated, and then the Si target is cleaned. After cleaning, the substrate containing the porous polyetheretherketone coating is fixed, evacuated, and then Ar and N2 are introduced to sputter and deposit the Si3N4 coating.

8. The preparation process according to claim 1, characterized in that: The substrate is first pretreated by grinding the substrate surface in turn with 240-mesh, 600-mesh and 1000-mesh sandpaper to remove surface oxides and impurities, then cleaning it and finally removing surface water stains.

9. The polyetheretherketone-silicon nitride composite nano bio-coating prepared according to the preparation process according to any one of claims 1 to 8.

10. The polyetheretherketone-silicon nitride composite nano bio-coating according to claim 9, characterized in that: A polyetheretherketone coating and a nano-Si3N4 coating are sequentially prepared on a substrate, wherein the surface of the polyetheretherketone coating is a fiber structure, and nanopores are distributed on the fiber structure.

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