Dynamics of Polymer Membrane Swelling in an Aqueous Suspension of Amino Acids. The Role of Isotopic Composition

— The interaction of Nafion polymer membrane with different amino acids has been experimentally investigated using photoluminescence spectroscopy. Experiments were performed with NaCl physiological solutions based on natural water (with a deuterium content of 157 ± 1 ppm) or on deuterium-depleted water (DDW) (deuterium content ≤1 ppm). This study was motivated by the fact that Nafion swelling in natural water is accompanied by “unwinding” of polymer fibers into the liquid bulk, whereas no unwinding occurs in DDW. In addition, the set of polymer fibers unwound into the liquid bulk is similar to the extracellular matrix (glycocalix) on a cellular membrane surface. It is of interest to analyze the role of unwound fibers in the interaction of amino acids with the polymer membrane surface. The interaction of amino acids with the membrane surface was found to induce luminescence quenching. We observed for the first time different dynamic modes arising during Nafion membrane swelling in a suspension of amino acids with different isotopic compositions, including trigger effects similar to the processes occurring in logic gates of computers.