Cytocompatibility of hydroxyapatite-coated titanium fiber mesh scaffold

Objectives: In the osteogenic potential, a bone graft substitute (BGS) requires the use of a suitable carrier or scaffold material. This study examined in vitro osteoblasts cytocompatibility to thin hydroxyapatite (HA) film deposited by laser ablation, in order to develop better surface conformation of plain titanium fiber mesh scaffolds (TFMS). Methods: TFMS were obtained by die-punching 5 mm in diameter discs from a 1.5 mm thick sheet of mesh composed of non-woven titanium fibers, 50 mm in diameter and a volumetric porosity of 87%. Thin HA film of 2,000 Å on titanium discs was made by an ArF excimer laser operating at a repletion rate of 10 Hz and annealed by heat radiation at 360 °C for 1 h. After annealing, the surface conformation of HA film on the TFMS was observed using energy dispersive analysis (EDX). Subsequently, the mouse immortalized stromal cell line (KUSA-A1) was cultured into the TFMS with or without HA film. Cell numbers and morphology observation were investigated by a fluorescence microscope for 1, 24 and 72 h. The differential expression of genes implicated in mouse extracellular matrix and adhesion molecules for KUSA-A1 was analyzed by real-time RT-PCR array technology. Results: EDX showed peaks of Ca and P with HA film on the TFMS. HA film on the TFMS increased the cell numbers for 1 h. In the presence of the HA film, KUSA-A1 had spread extensively and showed apparent actin stress fibers for 72 h. Several genes showed statistically significant changes in expression in response to alterations in HA film. The data were statistically significant by student's t-test (P<0.05, n=3) Conclusion: Based on these findings, HA film deposited by laser ablation showed an excellent cytocompatibility. The results obtained could lead to the development of more effective BGS.