title: Microprocessing of liquid plugs for bio/chemical analyses.
abstract: A microfluidic device and operation to handle liquid plugs for biochemical analyses were developed for efficient handling of plugs of many solutions. A major part of the device was a T-junction consisting of a main flow channel and a handling flow channel. Unit operations including attachment of plugs, division of a plug, sorting of plugs, and formation of plugs of various lengths enabled controlled sequential reactions in a microflow channel. Rapid mixing could easily be achieved by moving a plug formed by merging two plugs back and forth. The device could be used for efficient characterization of performance in bio/chemical sensing. In experiments using L-glutamate oxidase, plugs containing an enzyme or a substrate were formed, mixed sequentially, and the intensity of fluorescence from plugs of different concentrations of L-glutamate or pHs could be measured simultaneously. Cross-contamination of plugs by neighboring plugs poses a problem in using the same flow channel repeatedly. However, the influence could be minimized by using a cleansing plug placed between them in a sufficiently hydrophobic flow channel and by processing the plugs at a low velocity. The device can be a critical component for microprocessing in various bio/chemical analyses.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Sassa
authors.forename: Junji
authors.initials: J
authors.lastname: Fukuda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D018698:Glutamic Acid / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013302:Streptomyces / Q000201:enzymology
chemical_list: D012710:Serum Albumin, Bovine; D018698:Glutamic Acid; D006735:Horseradish Peroxidase; D000594:Amino Acid Oxidoreductases; C023061:L-glutamate oxidase