Numerical Estimation of Acetonitrile Adsorption into Simple Artificial Cell Membranes

The dynamic behaviour of lipid vesicles in response to the incorporation of toxic acetonitrile is investigated. Shape data from previous observations are used to estimate the incorporation of acetonitrile into a 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) vesicle. A bilayer-couple model is used to quantify the disparity in incorporation between the outer and inner leaflets. The model assumes that the prolate spheroid corresponds to a reduced volume vR=0.97 , when equal numbers of molecules incorporated into outer and inner leaflets. It further assumes a reduced area difference Delta a=1.140 . These disparities suggest that the difference in acetonitrile molecules incorporated into the outer and inner leaflets is Delta N=1.4x106 . The value indicates that the outer leaflet has more acetonitrile molecules than the inner leaflet because of the polarity of acetonitrile. These findings are the first step to clarifying the mechanism for acetonitrile to invade living cells.