(415d) Roles of Physicochemical Properties of “Nano-Platform of Membrane” in Asymmetric Recognition Function of Liposome Membrane

The techniques of separation and purification of chiral molecules are very important for synthesis of optically-active drugs because of a therapeutic effect and an adverse effect. Traditional methods of chiral separation requires “tailor-made” fitting of molecular binding state between host and guest molecules, but it is relatively expensive. In order to solve these problems, many researchers have been interested in the use of self-assembly systems, which form a flexible membrane with high molecular order. Liposome is a self-assembly of the phospholipid molecules, prepared in an aqueous solution, and can be regarded as a model biomembrane. Recent research has showed the possibility of the chiral recognition function of the liposome membrane through the binding of the dipeptide on the liposome membrane. It was revealed that chiral recognition was achieved by liposome membrane, which showed very drastic difference about the adsorption of amino acids at the difference of its chirality. In this research, the dynamic behavior of polarity of liposome membrane surface induced by adsorption of L-tryptophan (L-Trp) was investigated by some molecular probes. At the initial step of adsorption (around 24 hours incubation), surface polarity of liposome membrane changed by the adsorption of L-Trp, but did not by D-Trp. Finally, the adsorption of L-Trp showed Langmuir adsorption model around 48 hours incubation, so it was proposed that there were adsorption sites at the surface of liposome membrane with specific conformation formed by multiple phospholipids. From these results, it is expected to contribute to understanding of the mechanism of chiral recognition function induced by liposome membrane.