Takehiko Kitamori

A bead-bed immunoassay system suitable for simultaneous assay of multiple samples was constructed on a microchip. The chip had branching multichannels and four reaction and detection regions; the constructed system could process four samples at a time with only one pump unit. Interferon gamma was assayed by a 3-step sandwich immunoassay with the system coupled to a thermal lens microscope as a detector. The biases of the signal intensities obtained from each channel were within 10%, and coeffici

A rapid micromixer of fluids in a microchannel is presented. The mixer uses AC electroosmotic flow, which is induced by applying an AC voltage to a pair of coplanar meandering electrodes configured in parallel to the channel. To demonstrate performance of the mixer, dilution experiments were conducted using a dye solution in a channel of 120 microm width. Rapid mixing was observed for flow velocity up to 12 mm s(-1). The mixing time was 0.18 s, which was 20-fold faster than that of diffusional m

An integrated multireactor system for 2 x 2 parallel organic synthesis has been developed on a single glass microchip. Three-dimensional channel circuits in the chip were fabricated by laminating three glass plate layers. The fabrication method is a straightforward extension of the conventional one, and topological equivalence for any three-dimensional circuits can be constructed easily with it. 2 x 2 phase-transfer amide formation reactions, which constitute a simple model for combinatorial syn

A microchip-based enzyme-linked immunosorbent assay (microELISA) system was developed and interferon-gamma was successfully determined. The system was composed of a microchip with a Y-shaped microchannel and a dam structure, polystyrene microbeads, and a thermal lens microscope (TLM). All reactions required for the immunoassay were done in the microchannel by successive introduction of a sample and regents. The enzyme reaction product, in a liquid phase, was detected downstream in the channel us

The sensitive detection and quantification of DNA targets in the food industry and in environmental and clinical settings are issues of utmost importance in ensuring contamination-free food, monitoring the environment, and battling disease. Selective probes coupled with powerful amplification techniques are therefore of major interest. In this study, we set out to create an integrated microchemical chip that benefits from microfluidic chip technology in terms of sensitivity and a strong detectio

In a past decade, new research fields utilizing microfluidics have been formed. General micro-integration methods were proposed, and the supporting fundamental technologies were widely developed. These methodologies made various applications in analytical and chemical synthesis fields, and their superior performances such as rapid, simple, and high efficient processing have been proved. Recently, the space is further downscaling to the 10(1)-10(2) nm scale (extended-nano space). The extended-nan

We made a 'pile-up' microreactor in which ten levels of microchannel circuits were integrated to form a single glass entity. Solutions were distributed to each layer via cylindrical holes with a diameter much larger than that of the microchannel. Fabrication of the pile-up reactor was completed using only conventional photolithography, wet etching and thermal bonding techniques, and no special facilities or instruments were required. An amide formation reaction between amine in aqueous solution

We have developed a novel, practical micro-ELISA system for sensitive and rapid allergy diagnosis. The enzymatic reactions occurred under stopped-flow conditions, resulting in both high precision and high sensitivity. A BSA-biotin-avidin linker was introduced for the immobilization of water-soluble allergens on polystyrene microbeads, enabling immobilization of allergens in sufficient density to provide high sensitivity. Evaluation of the system's performance showed a good detection limit (2 ng/

Parallel multiphase microflows, which can integrate unit operations in a microchip under continuous flow conditions, are discussed. Fundamental physics, stabilization methods and some applications are shown.

By using characteristics of titania nanoparticles, a patterning and tuning method of microchannel surface wettability was developed for microfluid control. Titania modification of a microchannel provided a nanometer-sized surface roughness and the subsequent hydrophobic treatment made the surface superhydrophobic. Photocatalytic decomposition of the coated hydrophobic molecules was used to pattern the surface wettability which was tuned in the range from superhydrophobic to superhydrophilic unde