Extended-nano (EN) fluidics is a device technology utilizing EN channels which is smaller than wavelength of light, and its ultimate smallness brings unique aspects of separation chemistry. Smallness itself is a unique aspect, and analysis at pico, femto- and even atto-litter sample volume has been proved. In addition, almost all of the analyte molecules interact with the channel surface, and therefore, interaction between them and the surface dominates performance of analysis. Actually, our group has developed EN fluidic devices for chromatography and ELISA. at femto and sub-femto letter sample, and proved their excellent performance.
As we reported in some papers 1), EN space is surface dominant space, and the immobilization and modification of the channel surface is quite important for realizing the designed functions of EN fluidic devices. We introduced the surface modification method developed for microfluidic channels to the EN channels. In some cases, for example, modification by organic solutions which have low surface tension, it was not so difficult. However, usually, the ultimate smallness of the EN channels makes in-situ surface modification after bonding the fabricated substrate and cover glass quite difficult. Therefore, low temperature glass bonding method even at RT was developed.
In the lecture, some scientific aspects of fluids interacting with surface and technological aspects for surface control for analysis will be introduced.