earticle

영어

Micro and extended-nano (EN) fluidic device technology has brought evolutional progress in chemistry and medical biology although it is still on the way of development for practical use. In terms of the sample volume, analytical instrumentation technology is getting new tools to reduce the volume evolutionally, that is the micro and EN fluidic device providing nano, pico, femt and atto litter orders. Micro fluidic devices are almost in practical use. We proposed the micro unit operation (MUO) and continuous flow chemical processing (CFCP) concept for realizing chemical circuit on a microchip, and it became a chemical CPU for an analytical instrument in which the sample volume is nano to pico litter which is almost the same as single cell volume. The size region of 101-102 nm, that is EN space, is still unexplored area. In our group, we fabricated extended-nano channels into glass microchips, and succeeded in fluidic control and chemical processing such as chromatographic separation. In those EN fluidics, the MUO and CFCP concepts are kept. Actually, we applied the extended-nano channels and spaces to pico-litter immunoassay and atto-litter chromatography. Pico-litter is smaller than the volume of a living cell, and therefore, single cell single molecule analysis will be available. The atto-litter chromatography is really challenging, and some examples will be introduced in this talk. One of the critical issues of micro/EN fluidic technology is detection and determination. Especially, optical detection of non-fluorescent analytes is quite difficult, because optical pass length of channels is extremely short. Therefore, we developed the thermal lens micro-detection (TLM) method, and it was proved to be a very powerful detector even at zmol regions. However, optical pass length is a couple of orders shorter in EN, and it was still very difficult. Therefore, we got an idea of introducing differential interference contrast (DIC) optical configuration into TLM. DIC-TLM enabled us to detect optical absorption in EN optical pass length, and we could obtain chromatogram of non-fluorescent molecules. Principle of DIC is based on wave optics, and EN optical pass length was still sufficiently long comparing to wavelength for detection of phase shift induced by TL effect in EN channels. The combination of EN fluidics and DIC-TLM will be a powerful tool for single cell analysis and other various kinds of nano technologies.