Jinsei Miyazaki

J-aggregation of photochromic spiropyran in Langmuir-Blodgett films

Abstract The possibility of controlling the photochromic reactions of two different spiropyrans was investigated using the Langmuir-Blodgett technique. The spiropyran having a long chain formed an unstable monolayer without UV light and a stable monolayer with UV light. The spiropyran having two long chains, however, could form more stable monolayers with and without irradiation and the most stable monolayer was formed on mixing with n-octadecane in a molar ratio of 1:2. The assemblies of this monolayer, under UV irradiation at temperatures above 35 °C, exhibited a sharp and intense band at a longer wavelength, which could be assigned to the formation of J-aggregates. The half-decay period in the dark was 104 times longer than that of conventional spiropyrans. The possibilities of three-dimensional high density optical memory with this photochromic spiropyran are suggested.

Studies in the immuno fluoro sensing system

Biosensors need good selectivity, sensitivity and rapidity. These properties depend directly on the key materials such as antibody and pseudo antigen. In the development of lmmunosensors, therefore, we have intensively studied the preparation of monoclonal antibody (mAb), especially for a small molecule (hapten). Targeting methamphetamine as the antigen, we prepared mAb to suit our model biosensor concentrating on the immunogen design and mAb clone selection. These mAbs were then applied to three rapid assay methods based on fluorescence change. Finally, they were assembled in an automatic sensing system by modifying flow injection analysis (FIA).