Preliminary beta-tricalcium phosphate coating prepared by discharging in a modified body fluid enhances collagen immobilization onto titanium.

Because of its excellent scaffold properties toward bone cells, collagen has been recognized as a promising extracellular matrix protein for surface modification of titanium implants. Hydroxyapatite (HA) coatings have been investigated as a preliminary coating for collagen immobilization on titanium implants. However, the composition of HA-collagen is recognized as being difficult, and while many studies have suggested that biodegradable beta-tricalcium phosphate (beta-TCP) has better osteoconductivity than HA, the efficiency of preliminary beta-TCP coating for collagen immobilization on titanium surfaces has yet to be evaluated. This investigation aimed to evaluate the applicability of HA and beta-TCP coatings, prepared by discharging in modified body fluids, as preliminary collagen coatings. To increase collagen induction on preliminary HA and beta-TCP coatings, we used a new cathodic polarization method. X-ray photoelectron spectroscopy revealed that the bonding strength between the collagen NH(+) amino groups of collagen and phosphate (PO(4) (3-)) was greater on the beta-TCP coating than the HA coating. The preliminary beta-TCP coating was tightly crosslinked with RCOO(-) carboxyl groups of the collagen molecules and showed high cellular responses, even in the early stage of cell cultivation. Thus, this coating was found to be more effective than HA as a preliminary coating for collagen immobilization on titanium implants.