Biomolecular Surface Engineering of Materials for Controlling Bone Cell Adhesion and Spreading

Abstract

AbstractModel biomaterial surfaces were modified with a peptide that contained a -RGD- (Arg-GlyAsp) sequence, unique to bone sialoprotein, to determine its effect on strength of adhesion, spreading, and focal contact formation of primary bone-derived cells. Peptide surfaces were fabricated by using a heterobifunctional crosslinker to graft the peptide to surfaces (quartz and silicon). Contact angle measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy were used to confirm the chemistry and thickness of the overlayers. Furthermore, spectroscopic ellipsometry was used to estimate the density of immobilized peptide on metal oxide surfaces. A radial flow apparatus was used to measure the strength of adhesion on peptide grafted surfaces. Following 20 min of cell incubation, the strength of cell adhesion was significantly (p<0.05) higher on the -RGD- compared to -RGE- (control) surfaces. The mean area of cells contacting the -RGD- surface was significantly (p<0.05) higher than -RGE- surfaces. Vinculin staining revealed formation of focal contact patches on the periphery of bone cells incubated for 4 hr on the -RGD- surfaces; however, cells seeded on the -RGE- grafted surfaces formed little or no focal contacts. The methods of peptide immobilization utilized in this study can be applied to medical devices, biosensors, and diagnostic assays that require specificity in cell adhesion.