THE DETACHMENT STRENGTH AND MORPHOLOGY OF BONE-CELLS CONTACTING MATERIALS MODIFIED WITH A PEPTIDE SEQUENCE FOUND WITHIN BONE SIALOPROTEIN

Adhesion, spreading, and focal contact formation of primary bone-deriv ed cells on quartz surfaces grafted with a 15 amino acid peptide that contained a -RGD-(-Arg-Gly-Asp-) sequence unique to bone sialoprotein was investigated. The peptide surfaces were fabricated by using a hete rbifunctional crosslinker, sulfosuccinimidyal 4-(N-maleimidomethyl)cyc lohexane-1-carboxylate, to Link the peptide to amine functionalized qu artz surfaces. Contact angle measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy were used to confirm the chemist ry and thickness of the overlayers. A radial now apparatus was used to characterize cell detachment from peptide-grafted surfaces. After 20 min of tell incubation, the strength of cell adhesion was significantl y (p < 0.05) higher on the -RGD- compared to -RGE- (control) surfaces. Furthermore, the mean area of cells contacting the -RGD- was signific antly (p < 0.05) higher than -RGE- surfaces. Vinculin staining showed formation of small focal contact patches on the periphery of bone cell s incubated for 2 h on the -RGD- surfaces; however, few or no focal co ntacts were formed by cells seeded on the -RGE- grafted surfaces. The methods of peptide immobilization utilized in this study can be applie d to implants, biosensors, and diagnostic devices that require specifi city in cell adhesion. (C) 1997 John Wiley & Sons, Inc.