Effects of topographical surface modifications of electron beam melted Ti-6Al-4V titanium on human fetal osteoblasts.

The aim of the study was to assess the suitability of different Ti-6Al-4V surfaces produced by the electron beam melting (EBM) process as matrices for attachment, proliferation, and differentiation of human fetal osteoblasts (hFOB 1.19). Human osteoblasts were cultured in vitro on smooth and rough-textured Ti-6Al-4V alloy disks. By means of cell number and vitality and SEM micrographs cell attachment and proliferation were observed. The differentiation rate was examined by using quantitative real-time PCR analysis for the gene expression of alkaline phosphatase (ALP), type I collagen (Coll-I), bone sialoprotein (BSP) and osteocalcin (OC). After 3 days of incubation there was a significant higher vitality (p < 0.02) and proliferation (p < 0.02) of hFOB cells on smooth surfaces (R(a) = 0.077 microm) and compact surfaces with adherent partly molten titanium particles on the surface (R(a) </= 24.9 microm). On these samples cells spread over almost the whole surface. On porous surfaces with higher R(a) values, cell proliferation was reduced significantly. Quantitative real-time PCR analysis showed that the expression of osteogenic differentiation markers was not influenced by surface characteristics. Gene expression did not differ more than twofold for the different samples. Compact titanium samples with adherent partly molten titanium particles on the surface (R(a) </= 24.9 microm) fabricated by the EBM process turned out to be best suited for cell proliferation, while highly rough surfaces (R(a) >/= 56.9 microm) reduced proliferation of hFOB cells. Surface characteristics of titanium can easily be changed by EBM in order to further improve proliferation.