The Effect Of Biomimetic Multilayered Structure On Titanium Alloy Substrates On The Differentiation Of Osteoblasts

Due to good biocompatibility and mechanical properties, titanium and its alloyswere widely applied in orthopedic and dental implants. However, because their surfaceswere bioinert, after implantation, the integration between the implant and thesurrounding bone tissue was inert integration which will seriously affect the long-termlife of the implant.Inspired by the inorganic/organic hierarchical structure of nature bone, in this study,we fabricated bioactive multilayer films (Ti/LbL) on the surface of Ti6Al7Nb viaspin-assisted layer-by-layer assembly technique, with gelatin and chitosan as thepolyanion and polycation, respectively. On the other hand, we used hydroxyapatitenanowires as the intercalated materials and constructed biomimetic multilayers films(Ti/LbL/HA). Firstly, we synthesised HA nanowires and characterized it by TEM、SEM、FTIR、XRD. Secondly, we prepared biomimetic multilayer filmson the surface oftitanium via spin-assisted layer-by-layer assembly technique and viewed the crosssection of the lamellar film via SEM. The results indicated that the produced film hadan obvious lamellar structure. At the same time, we monitored the hydrophilityof everylayer by contact angle testing. Finally, we demonstrated the promotion of osteoblastsdifferentiation via in vitro experiments. After4and7days, osteoblasts on Ti/LbL/HAdisplayed significantly higher cell viability and ALP activity (p<0.01) than those onbare Ti. The morphology of osteoblasts were characterized by SEM and CLSM, and theimages showed that the substrates modified with biomimetic films were more beneficialfor osteoblasts to adhere and spread, meanwhile osteoblasts displayed better migrationcapacity. After7and14days, osteoblasts on Ti/LbL/HA displayed significantly highermineralization ability (p<0.01) than those on bare Ti substrate. We found that the geneexpression levels of OC and OPN in Ti/LbL/HA group were significantly higher than Tigroup (p<0.01). All these results demonstrated that the hierarchical structure depositedon Ti6Al7Nb could effectively promote the differentiation of osteoblast, which laidthescientific foundation for improving bone intergration.