Preparation Of Surface Modified BCP/PEEK Composites And Its Study Of Promoting Osseointegration

Bone defects caused by congenital and acquired diseases cause serious inconvenience and physical and mental pain,necessitating bone tissue repair.Polyetheretherketone(PEEK)is widely used in bone tissue repair due to its excellent mechanical properties,corrosion resistance,wear resistance,thermal stability,elastic modulus close to human bone,and good biocompatibility.However,PEEK is biologically inert and does not integrate quickly with surrounding bone tissue,leading to implant failure.Combining Biphasic Calcium Phosphate ceramics(BCP)composed of hydroxyapatite(HA)and β-Tricalcium Phosphate(β-TCP)with PEEK helps improve its biological inertness,while modification of surface microporous structure and strontium composition further enhances its bone repair ability.This study prepared BCP/PEEK composites by blending different proportions of HA and β-TCP with PEEK and injection molding.BCP was well dispersed in the PEEK matrix without occurring any new chemicals.The BCP/PEEK composite with5% HA,20% β-TCP,and 75% PEEK demonstrated the best overall performance: It increased the elastic modulus and compressive strength by 48.1% and 33.8%,reduced the tensile strength by 9.5%,and improved both hydrophilicity and protein adsorption compared with PEEK material.The in-vitro biomineralization experiment showed that the surface of the composite had more bone-like apatite generated on it.The BCP/PEEK composite was subjected to in-vitro co-culture experiments with osteoblasts,and in-vitro cell biology studies showed that the composite effectively promotes cell proliferation.Moreover,the BCP/PEEK composite was significantly superior to the PEEK material in terms of osteogenesis and osteogenic gene expression.The composite material,which passed the initial screening process,was used as the base matrix to create micro-pores of varied sizes through laser equipment.In vitrobiological and cell adhesion experiments indicated that micropores of 400 μm size exhibited better overall performance.Consequently,strontium hydroxide and polydopamine-coated modified composites were fabricated on the surface of the matrix.These modified composites were capable of releasing varying quantities of strontium ions in three different concentrations of 5 mg/m L,10 mg/m L,and 15mg/m L.Co-culturing osteoblasts with the composites showed a marked improvement in cell proliferation,cell adhesion,alkaline phosphataseand calcium deposition after incorporating strontium ions.Real-time quantitative PCR revealed that the appropriate amount of strontium ions led to the highest expression of osteogenic-specific transcription factors,alkaline phosphatase,and osteocalcin osteogenesis-related genes.Finally,the rat bone tissue was combined with the composite material.The results under alternating tangential fretting stimulation showed that the surface microporous BCP/PEEK-5Sr composite had the best binding force with bone tissue,which was 76±2.89 m N.Additionally,bone tissue staining demonstrated that this composite had the best bone tissue bone trabecular structure,the largest area,and the most number of osteocytes and osteoblasts.The surface of the material was also found to have significant cell adhesion.This thesis has 50 figures,5 tables,and 117 references.