Effects of Thin Hydroxyapatite Coating on Initial Response of Osteoblast-Like Cells

Abstract

To combine the bioinert titanium with the biological active coating of hydroxyapatite [HA, Ca10(PO4)6(OH)2] a new pulsed laser deposition(PLD) method was applied. The initial osteoblast-like MC3T3-E1 cell response to this thin HA coated(<1μm) surface was compared with non-coated surfaces. Cell responses on four different pure titanium surfaces, such as smooth titanium, HA coated smooth titanium, rough titanium and HA coated rough titanium, were compared. Cell morphology and attachment were examined by scanning electron microscopy after 6, 24 and 72 hrs of culture, cell proliferation by MTS assay after 3, 7 and 14 days. The differentiation of the cells was analyzed by real time PCR up to 21 days. The cells were well spread and attached on all surfaces and showed more irregular shapes on the HA coated specimens. They proliferated continuously on all specimens up to 14 days. Smooth surface specimens showed better cell proliferation than rough ones after 7 days, and the HA coated specimens demonstrated slightly greater MTS activity than the non-coated groups after 14 days. The surface topography affected cell proliferation initially however; there was no significant difference afterwards. Thin HA coating influenced the expression of some genes related with cell differentiation.