The diffusion of small ions through phospholipid bilayers

摘要: The passage of the alkali metals Li, Na, K, Rb, and Cs through saturated phosphatidylcholine membranes has been measured using particle induced gamma ray x‐ray emission to observe ions. Simultaneous measurements these five cations not possible with more traditional methods involving ion specific electrodes or radioactive tracers. To authors’ knowledge this is first time technique used in lipid bilayer research. leakage was determined for an incubation period 30 min at several temperatures which spanned melting temperature. dependence permeability on temperature, acyl chain length, size described theoretically terms density fluctuations bilayer. A rate depends mass observed. This shows that heavier faster it diffuses out vesicle. effect selectivity shown be most pronounced near temperature lipid. Moreover, suggests permeating entity a hydrated ion, rather than naked neutral, bound pair.