Comparative study of the effects of several n-alkanes on phospholipid hexagonal phases

The effects of a series of normal alkanes (decane, dodecane, tetradecane, hexadecane, and octadecane) on the hexagonal H-II structures containing dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC) were studied using x-ray diffraction and osmotic stress. The alkanes affect structural dimensions and the monolayer intrinsic curvature and bending modulus. The alkane effects are chain-length dependent and are attributed to their different distribution within the H-II structure. The data suggest that short-chain alkanes are more uniformly distributed within the H-II hydrocarbon regions and change the curvature and bending modulus of the monolayer, whereas longer-chain alkanes appear confined more to the interstitial region and do not change the curvature and bending modulus.