Surface oxide net charge of a titanium alloy Modulation of fibronectin-activated attachment and spreading of osteogenic cells

In the current study we have altered the surface oxide properties of a Ti6A14V alloy using heat treatment or radiofrequency glow discharge (RFGD) in order to evaluate the relationship between the physico chemical and biological properties of the alloys surface oxide The effects of surface pretreatments on the attachment of cells from two osteogenic cell lines (MG63 and MC3T3) and a mesenchymal stem cell line (C3H10T1/2) to fibronectin adsorbed to the alloy were measured Both heat and RFGD pretreatments produced a several fold increase in the number of cells that attached to fibronectin adsorbed to the alloy at a range of coating concentrations (0001-10 nM FN) for each cell line tested An antibody (HFN7 1) directed against the central integrin binding domain of fibronectin produced a 65-70% inhibition of cell attachment to fibronectin-coated disks indicating that cell attachment to the metal discs was dependent on fibronectin binding to cell integrin receptors Both treatments also accelerated the cell spreading response manifested by extensive flattening and an increase in mean cellular area The treatment induced increases in the cell attachment activity of adsorbed fibronectin were correlated with previously demonstrated increases in Ti6A14V oxide negative net surface charge at physiological pH produced by both heat and RFGD pretreatments Since neither treatment increased the adsorption mass of fibronectin these findings suggest that negatively charged surface oxide functional groups in Ti6A14V can modulate fibronectin's integrin receptor activity by altering the adsorbed protein's conformation Our results further suggest that negatively charged functional groups in the surface oxide can play a prominent role in the osseointegration of metallic implant materials Published by Elsevier B V