Multifunctional Ti metal with magnesium and cerium co-incorporation: a bioactive surface modification approach for improved in vitro and in vivo performances

Potential enhancements in surface characteristics and biological properties, such as antibacterial activity, cytocompatibility, and osseointegration behaviour of titanium (Ti) metal subjected to magnesium (Mg) and cerium (Ce) surface functionalization by the alkali-mediated modification approach, were explored in this study for advanced bone implant applications. Formation of a nanoporous surface layer incorporating both Mg and Ce ions, composed of anatase and rutile TiO₂ phases, with improved roughness and wettability profiles, was evidenced by FE-SEM, Raman spectroscopy, XPS, HR-TEM, AFM, and WCA analyses. In addition, the Mg-Ce co-functionalized Ti surfaces also demonstrated ∼80% antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, wherein the cytocompatibility towards MG-63 osteoblast-like cells was also prominent, as observed from cell viability, cytoskeletal attachment, metabolic activity, nuclear integrity, and mineralization assessments. Moreover, in vivo rat-tibial defect implantation using additively manufactured cancellous Ti scaffolds, with Mg-Ce surface functionalization, displayed better osseointegration responses in radiographic, micro-CT, and RT-PCR evaluations compared to the unmodified one. Together, the Mg-Ce co-incorporated porous TiO₂ surface layer over Ti metal provides a bioactive interface with beneficial surface characteristics that promotes antibacterial activity, cytocompatibility, and bone regeneration essential for dental and orthopedic implant applications.