title: Preconcentration of diluted biochemical samples using microchannel with integrated nanoscale Nafion membrane.
abstract: A microfluidic preconcentration device comprising a microchannel and a surface-patterned nanoscale Nafion membrane is proposed. Given the application of an electric field across the chip, the nanopore within Nafion membrane becomes ion selective due to an overlapping of the electric double layer. The resulting difference in flux of the co- and counter-ions within the membrane nanopore prompts the formation of a concentration gradient and leads to a gradual accumulation of the co-ions at the micro-nano junction. It is shown experimentally that the rate of concentration and the preconcentration factor both increase with an increasing electrical field intensity. The preconcentration performance in a straight microchannel is compared with that in a convergent microchannel using fluorescein disodium salt dehydrate and Fluorescein isothiocyanate (FITC)-labeled bovine serum albumin samples. The results show that the reduced cross-sectional area of the convergent microchannel increases the preconcentration factor compared to that obtained in a straight microchannel and yields a significant reduction in the preconcentration time.
authors: Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan.
authors: Chen-Chiao
authors: CC
authors: Chao
authors: Ping-Hsien
authors: PH
authors: Chiu
authors: Ruey-Jen
authors: RJ
authors: Yang
mesh_terms: D004867:Equipment Design; D019793:Fluorescein / Q000737:chemistry; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry; D005465:Fluorocarbon Polymers / Q000737:chemistry; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000737:chemistry
chemical_list: D005465:Fluorocarbon Polymers; C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; C040402:perfluorosulfonic acid; D016650:Fluorescein-5-isothiocyanate; D019793:Fluorescein