Swelling of Polymer Membrane in an Aqueous Protein Suspension: Photoluminescence Spectroscopy Experiments

Photoluminescence spectroscopy experiments have been performed to study the interaction of Nafion polymer membrane with protein particles upon swelling in a saline solution based on ordinary (natural) water or on deuterium-depleted water (DDW). This study was motivated by the fact that Nafion swelling in natural water is accompanied by efficient “unwinding” of polymer fibers into the liquid bulk, whereas no unwinding was found in DDW. In addition, the set of polymer fibers unwound into the liquid bulk is similar to the extracellular matrix (glycocalix) on the cellular membrane surface. It is of interest to refine the role of unwound fibers in the interaction of protein macromolecules with the polymer membrane surface. The interaction of protein macromolecules with the membrane surface was found to induce luminescence quenching/enhancement effects, specific for different proteins. In other words, different dynamic modes arise in the dependence of luminescence intensity from Nafion surface on the soaking time.