Covalent immobilization of collagen on titanium through polydopamine coating to improve cellular performances of MC3T3-E1 cells

Surface modification of orthopedic implants is critical for improving the clinical performance of these medical devices. Herein, collagen was covalently immobilized onto a titanium implant surface via a novel adherent polydopamine coating inspired by mussel adhesive proteins. The formation and composition of the collagen coating was characterized using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Fluorescent labeled collagen was also used to examine the formation and uniformity of the collagen coating. The resultant collagen coating with a polydopamine supporting substrate demonstrated better uniformity and distribution on the titanium surface compared to a physical adsorption of collagen. The covalent immobilized collagen coating is biologically active, as evidenced by its ability to enhance MC3T3-E1 cell adhesion, support cell proliferation and promote early stage osteogenic differentiation of pre-osteoblasts. Our study suggests covalent immobilization of collagen through the polydopamine coating might be an efficient way to improve the cellular performance of implant surfaces.