Fibrinogen and albumin adsorption on titanium nanoroughness gradients.

The influence of nanoscale roughness on protein adsorption has been efficiently studied through the application of Ti roughness gradients. Gradients were prepared by sputter deposition with a length of 76 mm and a range in RMS roughness varying linearly from 1 to 16 nm. They were then exposed to solutions containing either 1 mg/mL of fibrinogen or albumin. The amount of protein that adsorbed as a function of roughness was measured ex situ by electron microprobe analysis and compared to values obtained for smooth Ti films. The adsorption profiles of fibrinogen and albumin along the gradients were found to be highly similar when normalized by their respective amounts from smooth films, each showing a 50% increase in adsorption with roughness. A statistic called the average surface curvature was created to provide a plausible explanation for the similar adsorption behavior and connect findings from random topographies with earlier research on curved substrates like nanoparticles.