Bioactivation of zirconia surface with laminin protein coating via plasma etching and chemical modification

Abstract

Surface modification offers a promising alternative to provide bioactivity to implanted inert biomaterials, improving their integration and performance with living tissues. In this contribution, zirconia has been used as a substrate to investigate the biofunctionalization process, designed to add surface bioactivity to a bioinert biomaterial. We intended to attach laminin-5, known for its ability to bind epithelial cells in soft tissue, to the surface of the extracellular matrix protein. First, the zirconia surface was etched and activated with argon plasma and subsequently it was chemically functionalized with calcium and phosphate ions. Zirconia surface activation was monitored by means of a wettability test, whereas functionalization with calcium and phosphate ions was evaluated by confocal Raman microscopy, Z-potential and X-ray Photoelectron Spectroscopy (XPS). The binding of laminin-5 protein to the zirconia surface was carried out by means of adsorption and confirmed by XPS. Then, we used SEM and AFM to observe a homogeneous covering of globular protein over the zirconia surface. Furthermore, epithelial cell response over zirconia surfaces was assayed to show that biofunctionalized surfaces enhance cell adhesion to a greater extent than substrates without protein coating. Our results indicate how the zirconia surface can be modified using argon plasma, in order to enable its bioactivation with the laminin-5 protein.