Osteogenic and antibacterial ability of micro-nano structures coated with ZnO on Ti-6Al-4V implant fabricated by two-step laser processing

The biological performance of Ti-6Al-4V implant is primarily determined by their surface properties.However,traditional surface modification methods,such as acid etching,hardly make improvement in their osseointegration ability and antibacterial capacity.In this study,we prepared a multi-scale composite structure coated with zinc oxide(ZnO)on Ti-6Al-4V implant by an innovative technology of two-step laser processing combined with solution-assistant.Compared with the acid etching method,the physicochemical properties of surface significantly improved.The in vitro results showed that the particular dimension of micro-nano structure and the multifaceted nature of ZnO synergistically affected MC3T3-E1 osteogenesis and bacterial activities:(1)The surface morphology showed a‘contact guidance'effect on cell arrangement,which was conducive to the adhesion of filopodia and cell spreading,and the osteogenesis level of MC3T3-E1 was enhanced due to the release of zinc ions(Zn^(2+));(2)the characterization of bacterial response revealed that periodic nanostructures and Zn^(2+)released could cause damage to the cell wall of E.coli and reduce the adhesion and aggregation of S.aureus.In conclusion,the modified surface showed a synergistic effect of physical topography and chemical composition,making this a promising method and providing new insight into bone defect repairment.

A multifunctional nanocomposite hydrogel with controllable release behavior enhances bone regeneration

Autologous and allogeneic bone grafts remain the gold standard for repairing bone defects.However,donor shortages and postoperative infections contribute to unsatisfactory treatment outcomes.Tissue engineering technology that utilizes biologically active composites to accelerate the healing and reconstruction of segmental bone defects has led to new ideas for in situ bone repair.Multifunctional nanocomposite hydrogels were constructed by covalently binding silver(Ag^(+))core-embedded mesoporous silica nanoparticles(Ag@MSN)to bone morphogenetic protein-2(BMP-2),which was encapsulated into silk fibroin methacryloyl(SilMA)and photo-crosslinked to form an Ag@MSN-BMP-2/SilMA hydrogel to preserve the biological activity of BMP-2 and slow its release.More importantly,multifunctional Ag^(+)-containing nanocomposite hydrogels showed antibacterial properties.These hydrogels possessed synergistic osteogenic and antibacterial effects to promote bone defect repair.Ag@MSN-BMP-2/SilMA exhibited good biocompatibility in vitro and in vivo owing to its interconnected porosity and improved hydrophilicity.Furthermore,the multifunctional nanocomposite hydrogel showed controllable sustained-release activity that promoted bone regeneration in repairing rat skull defects by inducing osteogenic differentiation and neovascularization.Overall,Ag@MSN-BMP-2/SilMA hydrogels enrich bone regeneration strategies and show great potential for bone regeneration.