Bone cell responses to a low elastic modulus titanium alloy surface immobilized with the natural cross-linker genipin

In this study, we investigated various responses of human bone marrow mesenchymal stem cells (hMSCs) to a low elastic modulus Ti-24Nb-4Zr-8Sn (Ti2448) alloy surface that underwent immobilization using the natural cross-linker genipin. Specifically, hMSC's adhesion, proliferation, mineralization, and differentiation were evaluated. We also analyzed surface characteristics of the Ti2448 alloy, including chemistry, morphology, roughness, and wettability. Our results suggest that genipin immobilized Ti2448 has the potential to benefit orthopedic and dental implant applications. We found that the immobilization of genipin on a sand-blasted/acid-etched Ti2448 alloy surface significantly enhanced the mineralization of the extracellular matrix as well as the expression of certain osteogenic markers (bone sialoprotein and osteocalcin) in hMSCs. Conversely, surface roughness and hydrophilicity cannot be credited with the improved cellular responses observed in this study. The immobilization of genipin to produce a biomolecular surface on low elastic modulus Ti2448 alloy has considerable potential for bone implant applications.