Fibronectin adsorption on Fe-Cr alloy studied by XPS

Improved knowledge of the chemical composition of biomaterial surfaces and a better understanding of interactions between biomolecules and material surfaces will allow a more rational design of biomaterials. Surface characterisation of alloys before and after their interaction with proteins is an essential aspect of this approach. In this work, the interactions of fibronectin with stainless steel surfaces (Fe-17Cr alloy) were studied by X-ray photoelectron spectroscopy (XPS). Different solution concentrations of fibronectin were tested (0, 8, 60, 120 and 240 mu g ml(-1)) in interaction with the stainless steel sample. N 1s, C 1s, Cr 2p and Fe 2p core level spectra were systematically recorded and compared. The results indicate that fibronectin is adsorbed on the stainless steel surface. The alloy surface composition and oxide thickness are almost unchanged (Fe2O3 - Cr2O3 + Cr(OH)(3)) in presence of the protein, whatever the protein solution concentration. The isotherm of fibronectin adsorption at 37 degrees C was measured. A saturation is clearly reached for solution concentrations greater than 60 mu g ml(-1). On the plateau, the equivalent protein thickness is 6.3 nm, corresponding to one fibronectin monolayer. Copyright (C) 2006 John Wiley & Sons, Ltd.