Mussel-Inspired Peptide Coatings on Titanium Implant to Improve Osseointegration in Osteoporotic Condition

Osteoporosis greatly impairs in vivo implant osseointegration because of poor osteogenesis in osteoporotic conditions and the low bioactivity of implants, such as titanium-based biomaterials. Various surface engineering strategies, including unstable physical absorption or complex chemical conjugations, have been developed to biofunctionalize titanium implants and improve interfacial osseointegration. However, very few of them took into consideration the clinically challenging osteoporotic condition, as well as dual-functionalization of the implants for improvement of both osteoblast adhesion and osteogenesis. In this work, we combined two mussel-inspired bioactive peptides (i.e., with cell adhesive or osteogenic sequences) for one-step dual-functionalization of Ti screws via a facile self-organized multivalent coordinative interaction. In vitro study indicated that the biomimetic dual-functional coating could efficiently improve the osteogenesis of osteoporosis-derived mesenchymal stem cells despite of their impaired bone metabolism. Moreover, under osteoporotic in vivo condition, the dual-functional peptide coating on Ti screws could also give rise to significant enhancement of interfacial osteogenesis, newly formed bone condition, osseointegration, as well as implant mechanical stability. This is probably due to the integrin-targeted cell adhesive and osteogenic motifs on the modified Ti screws, which recovered the regular bone metabolism equilibrium between osteogenesis and osteoclastogenesis in an osteoporotic condition. We anticipate that the highly biomimetic peptides and one-step dual-functionalized strategy would provide a facile and effective means for improving the clinical outcome of Ti-based implants in patients with a disturbed bone metabolism.