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Critical Reviews™ in Biomedical Engineering
SJR: 0.207 SNIP: 0.376 CiteScore™: 0.79

ISSN Imprimir: 0278-940X
ISSN On-line: 1943-619X

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Volume 47, 2019 Volume 46, 2018 Volume 45, 2017 Volume 44, 2016 Volume 43, 2015 Volume 42, 2014 Volume 41, 2013 Volume 40, 2012 Volume 39, 2011 Volume 38, 2010 Volume 37, 2009 Volume 36, 2008 Volume 35, 2007 Volume 34, 2006 Volume 33, 2005 Volume 32, 2004 Volume 31, 2003 Volume 30, 2002 Volume 29, 2001 Volume 28, 2000 Volume 27, 1999 Volume 26, 1998 Volume 25, 1997 Volume 24, 1996 Volume 23, 1995

Critical Reviews™ in Biomedical Engineering

DOI: 10.1615/CritRevBiomedEng.v37.i3.10
pages 193-257

Miniaturized Microfluidic Formats for Cell-Based High-Throughput Screening

Sarvesh Upadhyaya
Department of Mechanical Engineering, McMaster University, Canada
Ponnambalam R. Selvaganapathy
Mechanical Engineering, McMaster University, Hamilton, Ontario, Canada

RESUMO

Cell-based high-throughput screening (HTS) has become an important method used in pharmaceutical drug discovery, and is presently carried out using robots and micro-well plates. A microfluidic-based device for cell-based HTS using a traditional cell-culture protocol would be a key enabler in miniaturization and in increasing throughput without consequent detrimental effects on the physiological significance of the screen. In this paper, we illustrate the advances in miniaturization of cell-based HTS, especially using microfabrication and microfluidics. We also detail a novel microfluidic HTS device targeted for cell-based assays using traditional non-compartmentalized agar gel as a cell-culture medium and electric control over drug dose. The basic design of this device consists of a gel layer supported by a nanoporous membrane that is bonded to microchannels underneath it. The pores of the membrane are blocked everywhere except in selected regions that serve as fluidic interfaces between the microchannel below and the gel above. Upon application of an electric field, nanopores start to act as electrokinetic pumps. By selectively switching an array of such micropumps, a number of spots containing drug molecules are created simultaneously in the gel layer. By diffusion, drugs reach the top surface of the gel where cells are to be grown. Based on this principle, a number of different devices can be fabricated using microfabrication technology. The fabricated devices include a single drug spot-forming device, a multiple drug spot-forming device, and a microarray drug spot-forming device. By controlling the pumping potential and duration, spots sizes ranging from 200 μm to 6 mm in diameter and having inter-spot distances of 0.4 to 10 mm have been created. The absence of diffusional transport through the nanoporous interfaces without an electric field is demonstrated. A number of representative molecules, including surrogate drug molecules (trypan blue and methylene blue) and biomolecules (DNA and protein) were selected for demonstration purposes. A dosing range of 50 to 3000 μg and a spot density of 156 spots/cm2 were achieved. The drug spot density was found to be limited by molecular diffusion in gel, so a numerical study was carried to determine ways to increase density. Based on this simulation, a diffusion barrier was proposed, which uses a specially dimensioned (having shallow grooves) gel sheet to reduce diffusion.