OSTEOBLAST ADHESION TO ORTHOPEDIC IMPLANT ALLOYS - EFFECTS OF CELL-ADHESION MOLECULES AND DIAMOND-LIKE CARBON COATING

In total joint arthroplasty, long-term outcomes depend in part on the biocompatibility of implant alloys. This study analyzed effects of sur face finish and diamond-like carbon coating on osteoblast cell adhesio n to polished titanium-aluminum-vanadium and polished or grit-blasted cobalt-chromium-molybdenum alloys. Osteoblast binding was tested in th e presence and absence of the cell adhesion proteins fibronectin, lami nin, fibrinogen, and vitronectin and was quantified by measurement of DNA content. Although adherence occurred in serum-free medium, maximal osteoblast binding required serum and was similar for titanium and co balt alloys at 2 and 12 hours. With the grit-blasted cobalt alloy, cel l binding was reduced 48% (p < 0.05) by 24 hours. Coating the alloys w ith diamond-like carbon did not alter osteoblast adhesion, whereas fib ronectin pretreatment increased cell binding 2.6-fold (p < 0.05). In c ontrast, fibrinogen, vitronectin: and laminin did not enhance cell adh esion. These results support the hypothesis that cell adhesion protein s can modify cell binding to orthopaedic alloys. Although osteoblast b inding was not affected by the presence of diamond-like carbon, this c oating substance may influence other longer term processes, such as bo ne formation, and deserves further study.