Early stages of human plasma proteins adsorption probed by Atomic Force Microscope.

Atomic Force Microscope (AFM) as a surface characterization technique has offered a great impulse in the advance of biocompatible materials. In this study AFM was implemented for the investigation of the early stages of adsorption of two human plasma proteins on titanium and hydrogenated carbon biocompatible thin films. The plasma proteins that were used were Human Serum Albumin and Fibrinogen, two of the most important proteins in human plasma. The concentration of the protein solutions was the same as that in human plasma. As the examined samples were soft, non-contact AFM mode was used to avoid their destruction. In order for the early stages of protein adsorption to be assessed, small incubation times were applied. AFM measurements in liquid buffer were also carried out, allowing the observation of the protein behaviour in an environment much closer to their native one. In addition, there was an assessment of the adsorption mechanism of the proteins on the above-mentioned biomaterials.