Synthesis and Characterization of Bioactive Coatings with Bone Regeneration Potential and Anti-Resorptive Effect

Bioactive coatings are of great interest for orthopedic applications, as they combine mechanical stability with biological functionality. In this study, stainless steel discs were coated with 45S5 bioactive glass doped with 1.0 wt% samarium by spin coating, followed by surface functionalization with benfotiamine through spraying. This strategy integrates three components: a metallic substrate as a stable and inexpensive support, a bioactive glass layer with well-known osteogenic potential, and a superficial organic layer of benfotiamine, a lipid-soluble analog of vitamin B1 with higher bioavailability. Samarium doping was selected based on previously reported antimicrobial potential against clinically relevant staphylococci, while the rationale for benfotiamine functionalization derives from literature describing vitamin B1 derivatives with anti-resorptive and osteogenic activity. The coatings were characterized by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) microscopy. Bioactivity was assessed by immersion in simulated body fluid (SBF), where phosphate bands indicated the formation of calcium phosphate phases (CaPs). Wettability tests showed a reduced contact angle after benfotiamine functionalization. Cytocompatibility was evaluated by LDH and MTT assays with MC3T3-E1 cells, suggesting overall biocompatibility and enhanced cell viability after 7 days for the benfotiamine-functionalized coatings. The present findings support a simple and cost-effective route to multifunctional coatings with potential relevance for future orthopedic applications.