Soft X-ray Spectromicroscopy of Protein Interactions with Phase-Segregated Polymer Surfaces

Quantitative spectro-microscopic characterization of the interfaces between polymers and relevant proteins helps understand fundamental issues of protein polymer interactions and can provide insights into biocompatibility. Synchrotron based X-ray photoemission electron microscopy (X-PEEM) and scanning transmission X-ray microscopy (STXM) are being used to study distributions of proteins adsorbed on chemically heterogeneous polymer surfaces with similar to 30 nm spatial resolution. The relevant contrast in each technique is X-ray absorption spectroscopy which provides speciation and quantitation of both adsorbed proteins or peptides (and in combinations), simultaneously with chemically sensitive imaging of the underlying polymer substrate. An overview of recent progress in this field is given, along with some comparisons to complementary techniques (AFM and TOF-SIMS) for investigating protein-polymer interfaces.