Multifunctional alumina scaffolds with enhanced bioactivity and antimicrobial properties for bone tissue engineering

Inert ceramic implants suffer from significant complications such as lack of osseointegration, biofilm formation, and infections, necessitating the development of novel materials with both osteogenic and antibacterial properties to prevent implant failure. In this study, we aimed to multifunctionalize a tridimensional macroporous alumina scaffold with a biomimetic calcium phosphate (CaP) coating combined with a silver-based extra-thin film to enhance bioactivity and provide an additional antibacterial effect. The porous alumina scaffolds were fabricated through a powder metallurgy technique, followed by biomimetic deposition and DC magnetron sputtering. The coatings were characterized using SEM/EDS and AFM measurements to examine their morphology and topography. To evaluate the osteoconductive response of the materials, in vitro tests were conducted by immersing the samples in Simulated Body Fluid (SBF). The bioactivity tests revealed that the CaPAgO coating, in line with the roughness surface and free surface energy values, exhibited a higher Ca/P ratio formation. This indicated an increased affinity for apatite adhesion, ultimately leading to a higher osseointegration ability compared to the CaP-Ag coating. Furthermore, the CaP-AgO coating demonstrated superior activity against S. aureus. These findings demonstrate the potential of the multifunctional coatings to address the challenges associated with inert ceramic implants by promoting bioactivity and combating bacterial infections.