Effect of phosphatidylcholine vesicle size on chirality induction and chiral discrimination

The effect of the size of phosphatidylcholine (PC) vesicles on the induction of chirality and chiral discrimination was examined. Three kinds of vesicles formed with l ‐dimyristoyl, l ‐dipalmitoyl, or egg yolk PCs induced circular dichroisms (CDs) with the sign and intensity of the Cotton effect different from those of monomeric PCs. The CD intensity of the vesicles increased with a decrease in the vesicle size. Furthermore, the helicity of heterohelicene derivatives in a rapid equilibrium between right‐handed (P) and left‐handed (M) enantiomers was biased toward the M enantiomer side in l ‐PC vesicles, implying chiral discrimination by the vesicles. The extent of the bias toward the M enantiomer increased with an increase in vesicle size. Both the chirality induction and chiral discrimination were enhanced in a low‐fluidity gel phase in comparison with those in a high‐fluidity liquid‐crystalline phase for every kind of vesicle of every size examined. © 2006 Wiley‐Liss, Inc. Chirality