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.

Glow discharge plasma treatment of titanium plates enhances adhesion of osteoblast-like cells to the plates through the integrin-mediated mechanism.

PURPOSE: Initial adhesion of cells to implant surfaces and subsequent behavior of the cells are important determinants for biocompatibility of the implants. It was previously reported that both adhesion of MC3T3-E1 osteoblast-ike cells to titanium (Ti) plates and their differentiation into more mature cells on the plates were stimulated by treatment of the plates with glow discharge plasma (GDP). However, the mechanisms of these processes have not yet been identified. In this study, the adhesion and differentiation mechanism of osteoblast-like cells to Ti with and without GDP were investigated. MATERIALS AND METHODS: The adhesion and differentiation mechanism of MC3T3-E1 osteoblast-like cells to Ti, with and without GDP, were investigated by cultivation in serum-free medium and use of a competitive inhibition test to examine the influence of extracellular matrix proteins contained in the serum and to identify cell binding proteins. In addition, the amount of fibronectin adsorption on each Ti plate was investigated by enzyme-linked immunosorbent assay and fluorescein isothiocyanate labeling. Furthermore, the stress fiber formation and morphology of cells on each plate were evaluated microscopically. RESULTS: Adherent cells on Ti plates, with and without GDP, were significantly reduced in serum-free conditions and the presence of RGDS (Arg-Gly-Asp-Ser) peptides. Fibronectin adsorption on titanium plates was increased by GDP. Furthermore, stress fiber formation of cells was extremely progressive on the Ti plates treated with GDP and was not observed on the cells inhibited by RGDS peptide. DISCUSSION: These results suggest that RGDS containing serum proteins have a major role in regulating specific adhesion of cells to Ti, and GDP promoted cell adhesion and differentiation on Ti by increasing the adsorption of proteins. CONCLUSION: According to this study, the adhesion and differentiation mechanism of osteoblast-like cells to Ti, with and without GDP, can be obtained.