title: A microfluidic device to establish concentration gradients using reagent density differences.
abstract: Microfabrication has become widely utilized to generate controlled microenvironments that establish chemical concentration gradients for a variety of engineering and life science applications. To establish microfluidic flow, the majority of existing devices rely upon additional facilities, equipment, and excessive reagent supplies, which together limit device portability as well as constrain device usage to individuals trained in technological disciplines. The current work presents our laboratory-developed bridged μLane system, which is a stand-alone device that runs via conventional pipette loading and can operate for several days without need of external machinery or additional reagent volumes. The bridged μLane is a two-layer polydimethylsiloxane microfluidic device that is able to establish controlled chemical concentration gradients over time by relying solely upon differences in reagent densities. Fluorescently labeled Dextran was used to validate the design and operation of the bridged μLane by evaluating experimentally measured transport properties within the microsystem in conjunction with numerical simulations and established mathematical transport models. Results demonstrate how the bridged μLane system was used to generate spatial concentration gradients that resulted in an experimentally measured Dextran diffusivity of (0.82 ± 0.01) × 10(-6) cm(2)/s.
authors.affiliation: Department of Biomedical Engineering, The City College of The City University of New York, Room 403D, Steinman Hall, 160 Convent Avenue, New York, NY 10031, USA.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Kong
authors.forename: Richard A
authors.initials: RA
authors.lastname: Able
authors.forename: Veronica
authors.initials: V
authors.lastname: Dudu
authors.forename: Maribel
authors.initials: M
authors.lastname: Vazquez
mesh_terms: D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D003198:Computer Simulation; D003911:Dextrans; D004867:Equipment Design; D020342:Finite Element Analysis; D005456:Fluorescent Dyes; D057446:Hydrodynamics; D007202:Indicators and Reagents; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000706:statistics & numerical data; D055616:Microtechnology; D008962:Models, Theoretical
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes; D007202:Indicators and Reagents