PHOTO-CONTROLLED EXTRACTION AND ACTIVE-TRANSPORT OF AMINO-ACIDS BY FUNCTIONAL REVERSED MICELLES CONTAINING SPIROPYRAN DERIVATIVES

In a reversed micellar n-decane solution, a spiropyran derivative 3',3'-dimethyl-1'-octadecyl-6-nitrospiro(2H-benzopyran-2,2'-indoline) (PC18) showed normal photochromism, and the reversed micelles provided polar microenvironment increasing stability of a zwitterionic merocyanine (MC) form of PC18. Though the reversed micelles of tetraethyleneglycol dodecylether (TEGDE) alone in n-decane had relatively low ability to extract amino acid from aqueous solutions, the PC18-incorporated TEGDE reversed micelles in n-decane showed good photo-controlled extraction of zwitterionic amino acid under UV-irradiation and release under VIS-irradiation. Extent of the extracted amino acid was higher for tryptophane (Trp) bearing hydrophobic side chain than alanine (Ala), showing amino acid selectivity. Photo-driven active transport of amino acid across a liquid membrane was attained by the PC18-incorporated TEGDE reversed micellar carrier in a water/n-decane/water three-phase system, where one side of an aqueous/organic interface was irradiated by the UV-light and the other side by the VIS-light. When Trp and Ala were present in the aqueous solution, Trp was selectively transported.