Phase-transformed lactoferrin/strontium-doped nanocoatings enhance antibacterial, anti-inflammatory and vascularised osteogenesis of titanium.

Failure of orthopedic implants due to localized bacterial infections, inflammation and insufficient blood supply is always problematic. In this study, strontium-doped titanium dioxide nanotubes (STN) were firstly prepared on titanium surface, and then lactoferrin (LF) was loaded into strontium-doped nanotubes (STN) by the phase transition method, eventually the LF/TCEP-STN composite coating was successfully prepared. With the innate antimicrobial properties of LF, LF/TCEP-STN was effected against E. coli and S. aureus. Cellular assays showed that RAW264.7 (immune), HUVEC (angiogenic) and MC3T3-E1 (osteogenic) exhibited good adhesion and proliferative activity on the surface of LF/TCEP-STN. At the molecular level, LF/TCEP-STN modulated RAW264.7 polarization toward M2-type while promoting MC3T3-E1 differentiation toward osteogenesis. Meanwhile LF/TCEP-STN coating effectively promoted angiogenesis. The results of the bone defect model with or without infection demonstrated that the LF/TCEP-STN material had good anti-inflammatory, antibacterial, and vascularization-promoting osteogenesis. In addition, LF/TCEP-STN offered excellent blood compatibility and biosafety. As a multifunctional coating on implant surfaces, the study's results highlighted the viability of LF/TCEP-STN and offered fresh concepts for the clinical design of next-generation artificial bone implants with antibacterial, anti-inflammatory, and osteogenic properties.