Effect of surface roughness of the titanium alloy Ti-6Al-4V on human bone marrow cell response and on protein adsorption

The effect of surface roughness of the titanium alloy Ti-6Al-4V (Ti alloy) on the short- and long-term response of human bone marrow cells in vitro an d on protein adsorption was investigated. Three different values in a narro w range of surface roughness were used for the substrata (R-alpha: 0.320, 0 .490 and 0.874 mum). Cell attachment, cell proliferation and differentiatio n (alkaline phosphatase specific activity) were determined past various inc ubation periods. The protein adsorption of bovine serum albumin and fibrone ctin, from single protein solutions, on rough and smooth Ti alloy surfaces was examined with two methods, X-ray photoelectron spectroscopy (XPS) and r adiolabeling. Cell attachment and proliferation were surface roughness sens itive and increased as the roughness of Ti alloy increased. No statisticall y significant difference was observed in the expression of ALP activity on all three Ti alloy surfaces and culture plastic. Both methods, XPS and prot ein radiolabeling, showed that human serum albumin was adsorbed preferentia lly onto the smooth substratum. XPS technique showed that the rough substra tum bound a higher amount of total protein (from culture medium supplied wi th 10% serum) and fibronectin (10-fold) than did the smooth one. The cell a ttachment may be explained by the differential adsorption of the two protei ns onto smooth and rough Ti alloy surfaces. (C) 2001 Elsevier Science Ltd. All rights reserved.