Concomitant silanization and controlled fibronectin adsorption on S53P4 bioactive glass enhances human adipose stem cells spreading and differentiation

Abstract

Orthopedic disorders are increasing in our society due to population aging. Numerous biomaterials have been developed to support bone regeneration, however showing a strong discrepancy between in vitro and in vivo results. This has been attributed to a lack of knowledge about protein adsorption, an early step occurring after biomaterial implantation. Bioactive glass S53P4 is clinically accepted for orthopedic applications pertaining to its osteoconductive and osteogenic behavior. However, its interactions with proteins are still unclear. To better understand the impact of surface chemistry on the glass-protein interactions, bare and silanized S53P4 were placed in contact with fibronectin (fn), in static and dynamic conditions. The surfaces were characterized by zeta potential, confocal microscopy and FTIR-ATR spectroscopy.The impact of fn on the cell response was assessed by live-dead, proliferation and morphology tests, using human adipose stem cells (hASCs). Both S53P4 and silanized-S53P4 showed good cell viability. Fn was found to affect cell alignment on both bare and silanized substrates. The impact of the surface treatments on osteogenesis was evaluated studying the expression of relevant osteogenic markers (hDLX5, hRUNX2A, hOSTERIX), which was particularly promoted by the concomitant action of silanization and fn coating.