Study On The Surface Composition And Structure Regulation Of Polyetheretherketone Material For Bone Implantation

Polyetheretherketone(PEEK)is a promising alternative metal implant for bone reconstruction,trauma,cranio-maxillofacial and dental applications as a semi-crystalline polymer.Its elastic modulus(3-4 GPa)is closer to cortical bone,good biocompatibility and low friction coefficient,various and flexible processing methods,chemical corrosion resistance,natural radiation transparency and compatibility with Magnetic Resonance Imaging(MRI),etc.However,its disadvantage as an implant is that it lacks the function of vascularization and osteogenesis due to the inert surface,which hinders its clinical application.In addition,postoperative infection and oxidative stress caused by implants remain two major problems facing medical materials.To solve these problems,the surface modification(composition and structure regulation)of PEEK to realize the loading and slow release of drugs or proteins in this work.The effects of surface composition and structure regulation on material properties and biological properties were studied.The main research results are as follows:(1)Early bacterial infection is an important clinical failure reason of implants,consider the problem of resistance to drugs like antibiotics or antimicrobial peptides,etc.We use metal ions as antibacterial material,the preparation of a kind of porous materials,the materials can release a number of different metal ions during degradation and the porous structure was used to load osteogenic drugs to promote the osteogenic properties of the implants.we bonded a dual metal-organic framework coating(Zn-Mg-MOF74)to PEEK by using a mussel-inspired polydopamine interlayer(PDA),and then dexethasone(DEX)was loaded into the coating.The results showed that the multifunctional coating released Mg²⁺,Zn²⁺,2,5-dihydroxyterephthalic acid(DHTA)and DEX and formed an alkaline microenvironment,and was able to exhibit strong antibacterial performance against Escherichia coli(E.coli)and Staphylococcus(S.aureus)aureus with good bioactivity and osteogenic differentiation ability.Moreover,Mg²⁺can promote the formation of blood vessels in the local bone tissue,which facilitates the reconstruction of the vascular system during bone regeneration.In addition,The femoral injury model and subcutaneous infection model of SD rats was used to verify the results.This work indicated that the multifunctional Zn-Mg-MOF74 coating loaded with dexamethasone prepared on the PEEK surface had good bacteriostasis,angiogenesis and osteogenesis,and had great clinical application potential as bone graft materials.(2)Oxidative stress damage can reduce the biological function of cells,which is another key factor in implant failure.We proposed a method of modifying PEEK with nacre water-soluble matrix protein(WSM)with antioxidant stress properties to improve its osteogenic activity.The freeze drying method is adopted to WSM loaded into the sulfonated PEEK surface with three-dimensional porous,and the protein content was regulated.Antioxidant stress test showed that the sulfonated PEEK loaded with WSM had good antioxidant stress ability,and the sample loaded with WSM at the concentration of 50?g/m L was the best.In vitro cellular experiments showed that samples loaded with WSM better promoted the proliferation,ALP activity,and ECM deposition of rat bone marrow mesenchymal stem cells(r BMSCs),and the samples with the highest antioxidant capacity had superior osteogenic activity.This study showed that the PEEK sample surface modified with WSM could remove or reduce the free radicals generated by cell metabolism reaction and promote the differentiation of osteoblasts,it broadens the thinking and method for the application of WSM.