The Study On The Preparation And Osteogenic Potential In Vitro Of Surface Modified Carbon Fiber Reinforced Polyetheretherketone Implants

Objective: Polyetheretherketone(PEEK)has attracted more and more attention in dentistry and orthopedics due to its good biocompatibility,chemical stability and low elastic modulus.However,polyetheretherketone is a bioinert material with low surface activity,which is not conducive to osseointegration,and its mechanical properties are lower than human bone.The purpose of this study is to investigate the physicochemical properties and osteogenic properties of carbon fiber reinforced polyetheretherketone implants modified by amino group surface modification,which provides a theoretical basis for the application of PEEK in oral implants.Method: In this study,carbon fiber reinforced polyetheretherketone with different contents were prepared by injection molding method,the carbon fiber reinforced polyetheretherketone with the best mechanical properties were screened through mechanical property detection.The selected samples were modified by radio frequency low-temperature modification technology,and then the physicochemical properties and osteogenic potential in vitro of the samples were detected.Pure titanium was used as the control group for the following tests: 1.The physical properties of the samples were detected.The surface topography,roughness and hydrophilicity of samples were detected by Scanning electron microscopy(SEM),Atomic force microscopy observation(AFM)and Water contact angle(WCA).2.The chemical properties of the samples were detected,and the chemical elements and chemical functional groups on the surface of samples were detected by X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR).3.Mg-63 cells were inoculated on the samples and cultured for 6 hours.The effects of amino group surface modification on the adhesion of osteoblasts were observed by Scanning electron microscopy and DAPI staining;After 1,3 and 7 days of co-culture,the effect of amino group surface modification on the proliferation of osteoblasts was detected by CCK-8 analysis.4.The MG-63 cells were inoculated on the surface of samples and co-cultured for 7 and 14 days,then the alkaline phosphatase(ALP)activity was determined.After 21 days of culturing,alizarin red staining was quantitatively analyzed to detect the expression level of extracellular matrix(ECM)mineralization.5.Real-time quantitative polymerase chain reaction(q RT-PCR)and enzyme-linked immunosorbent assay(ELISA)were used to detect the expression of osteogenic genes and proteins in MG-63 cells after co-culture on the samples for 7 and 14 days,which were used to evaluate the effect of amino group surface modification on the osteogenic differentiation of MG-63 cells.Results: 1.10%,20%,30%,and 40% contents of carbon fiber reinforced polyetheretherketone composites were prepared respectively,SEM showed that polyetheretherketone combined well with carbon fiber.The results of mechanical properties detection showed that carbon fiber enhanced the mechanical properties of composites,and 30% carbon fiber reinforced polyetheretherketone(30%CFR-PEEK)had the best mechanical properties.Therefore,this group of samples were selected for surface modification by radio frequency low-temperature plasma(A-30%CFR-PEEK),and the physical and chemical properties and osteogenic potential in vitro of the samples were tested.2.The physical properties of samples detection results: SEM results showed that no significant effect in surface morphology was found by amino group modification.AFM results showed that surface roughness on A-30%CFR-PEEK(Ra = 231 nm)was significantly lower than 30%CFR-PEEK(Ra = 480 nm),which was similar to the titanium(Ra = 221 nm).The results of WCA showed that the samples changed from hydrophobic surface to hydrophilic surface after amino group modification.3.The chemical properties of samples detection results: XPS results showed that C and O elements could be detected on 30%CFR-PEEK,C,O,and N(16.8%)elements could be detected on A-30%CFR-PEEK,C,O,N,and F(2.69%)elements could be detected on A-30%CFR-PEEK labeled by TFBA.FTIR images showed that after surface modification,amino characteristic peaks appeared in the range of 3380 cm-1 to 3200 cm-1 on A-30%CFR-PEEK,indicating that amino groups were introduced on A-30%CFR-PEEK.4.The results of cell adhesion showed that MG-63 cells on A-30%CFR-PEEK were elongated spindle shaped,with a large adhesion area,and the number of osteoblasts was more than 30%CFR-PEEK.The CCK-8 results showed that the OD value on A-30%CFR-PEEK was higher than 30%CFR-PEEK after 1,3 and 7 days.5.The MG-63 cells were cultured with the samples for 7 and 14 days,the alkaline phosphatase activity on A-30%CFR-PEEK was higher than 30%CFR-PEEK and titanium control group.After 21 days,the extracellular matrix on A-30%CFR-PEEK was higher than 30%CFR-PEEK,which was similar to titanium.6.The results of q RT-PCR showed that the gene expression levels of ALP,COL-1,OCN and RUNX2 in A-30%CFR-PEEK were significantly higher than in 30%CFR-PEEK and titanium control group after 7 days.After 14 days,the gene expression levels of COL-1,OCN and RUNX2 in A-30%CFR-PEEK were significantly higher than those in 30%CFR-PEEK,the gene expression levels of ALP in A-30%CFR-PEEK was significantly lower than those in 30%CFR-PEEK and titanium control group.7.The results of ELISA showed that the protein expressions of ALP,COL-1 and OCN in A-30%CFR-PEEK were significantly higher than 30%CFR-PEEK,and there was no significant difference in the protein expression level of RUNX2 before and after amino group modification after 7 days.After 14 days,the gene expression levels of ALP,COL-1 and OCN in A-30%CFR-PEEK were significantly higher than 30%CFR-PEEK and titanium control group,and there was no significant difference in the protein expression levels of RUNX2 before and after amino group modification.Conclusion: Carbon fiber reinforced polyetheretherketone with different content was prepared by injection molding method.The addition of carbon fiber enhanced the mechanical properties of the materials,30%CFR-PEEK had the best mechanical properties.Through radio frequency low temperature plasma surface modification technology,amino functional groups were introduced on the surface of 30% CFR-PEEK.Amino group surface modification could significantly improve the hydrophilic of samples,promoted the osteoblast adhesion,proliferation and alkaline phosphatase activity,mineralization of extracellular matrix,and osteogenesis related gene and protein expression.