X-ray Spectromicroscopy Study of Protein Adsorption onto a Chemically Patterned Surface

Abstract

<p>Protein adsorption, the first event in the interaction of tissue with a foreign material, is a complex process. Understanding and controlling protein adsorption is an important issue in biomaterials. Many different techniques have been developed to study protein adsorption from different aspects. In this work, two soft X-ray spectromicroscopy techniques, photoemission electron microscopy (X -PEEM) and scanning transmission x-ray microscopy (STXM) were used to map the interaction of blood proteins on a phase segregated polymer film polystyrene/ polymethyl methacrylate (PSIPMMA) blend. The two techniques provide high chemical sensitivity, through near edge X-ray absorption fine structure (NEXAFS) spectroscopy, and high spatial resolution (~50 nm).</p> <p>As a surface sensitive technique, X-PEEM was used to study adsorption of albumin onto a PS/PMMA blend under different conditions (concentration, adsorption time, pH, temperature and ionic strength), as well as to compare adsorption of albumin and fibrinogen. STXM, a less surface sensitive technique, was used to study albumin adsorption in the presence of a overlayer protein solution, a study which can not be conducted using X-PEEM.</p> <p>The results give quantitative spatial distributions of adsorbed protein on chemically different regions of the PSIPMMA blend at the studied conditions. This helps understand protein adsorption in a way different from other techniques. Through technique development and an intensive study of the albumin covered PS/PMMA system, this work has made a contribution to development of biomaterials.</p>