Peptide-immobilized nanoporous alumina membranes for enhanced osteoblast adhesion

Bone tissue engineering requires the ability to regulate cell behavior through precise control over substrate topography and surface chemistry. Understanding of the cellular response to micro-environment is essential for biomaterials and tissue engineering research. This research employed alumina with porous features on the nanoscale. These nanoporous alumina surfaces were modified by physically adsorbing vitronectin and covalently immobilizing RGDC peptide to enhance adhesion of osteoblasts, bone-forming cells. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize the modified nanoporous alumina surface. Survey and high-resolution C1s scans suggested the presence of RGDC and vitronectin on the surface and SEM images confirmed the pores were not clogged after modification. Cell adhesion on both unmodified and modified nanoporous alumina was compared using fluorescence microscopy and SEM. RGDC was found to enhance osteoblast adhesion after 1 day of culture and matrix production was visible after 2 days. Cell secreted matrix was absent on unmodified membranes for the same duration. Vitronectin-adsorbed surfaces did not show significant improvement in adhesion over unmodified membranes.