A diffusion based long-range and steady chemical gradient generator on a microfluidic device for studying bacterial chemotaxis. (4th February 2016)

• Record Type: Journal Article
• Authors: Murugesan, Nithya; Singha, Siddhartha; Panda, Tapobrata; Das, Sarit K
• Is Part Of: Journal of micromechanics and microengineering. Volume 26:Number 3(2016:Mar.)
• Publication Date: 2016-02-04
• Subjects: gradient generator -- chemotaxis -- diffusion based device -- long range -- steady chemical gradient; Microelectromechanical systems -- Periodicals; Micromechanics -- Periodicals; 621.38105
• DOI: 10.1088/0960-1317/26/3/035011
• Languages: English
• ISSNs: 0960-1317

Abstract

Abstract: Studies on chemotaxis in microfluidics device have become a major area of research to generate physiologically similar environment in vitro . In this work, a novel micro-fluidic device has been developed to study chemo-taxis of cells in near physiological condition which can create controllable, steady and long-range chemical gradients using various chemo-effectors in a micro-channel. Hydrogels like agarose, collagen, etc, can be used in the device to maintain exclusive diffusive flux of various chemical species into the micro-channel under study. Variations of concentrations and flow rates of Texas Red dextran in the device revealed that an increase in the concentration of the dye in the feed from 6 to 18 μ g ml −1, causes a steeper chemical gradient in the device, whereas the flow rate of the dye has practically no effect on the chemical gradient in the device. This observation confirms that a diffusion controlled chemical gradient is generated in the micro-channel. Chemo-taxis of E. coli cells were studied under the steady gradient of a chemo-attractant and a chemo-repellent separately in the same chemical gradient generator. For sorbitol and NiSO4 ·6H2 O, the bacterial cells exhibit a steady distribution in the micro channel after 1 h and 30 min, respectively. From the distribution of bacterial population chemo-tactic strength of the chemo-effectors was estimated for E. coli . In a long microfluidic channel, migration behavior of bacterial cells under diffusion controlled chemical gradient showed chemotaxis, random movement, aggregation, and concentration dependent reverse chemotaxis.