Interactions between xenon and phospholipid bicelles studied by 2H/129Xe/131Xe NMR and optical pumping of nuclear spins

Abstract: The interactions between xenon and DMPC/DHPC bicelles (q =3.5%,7.5%w/v) were studied via 2H, 129Xe, 131Xe, and optically enhanced 129Xe NMR. The chemical shifts, linewidths, and quadrupolar couplings of the xenon/bicelle NMR signals were correlated with different regions of the bicellar phase diagram. The addition of xenon (<70mM) was observed to reduce the temperature-onset of bicelle alignment by several degrees, in quantitative agreement with effects previously observed with chloroform; however, the stable liquid-crystalline range was not significantly reduced. Preliminary laser-polarized xenon/bicelle studies yielded 129Xe T 1 values of ∼120s, long enough to permit a variety of planned experiments. [Copyright &y& Elsevier]