Characterization of transport in microfluidic gradient generators

Abstract

We present a two-dimensional model that describes the concentration profile of a class of previously reported microfluidic devices which are of particular interest in cellular taxis research. The devices generate stable concentration gradients by mixing and dividing two or more external inputs into a large number of discrete streams. This study focuses specifically on modeling the confluence of the discrete streams in a long chamber. We derive a closed-form solution for gradient generators with any arbitrary number of sampling streams. By relating the physical dimensions to the Péclet number, we create a model independent of flow rate and therefore dependent only on the specific nature of the boundary condition provided by the upstream network. As a result, the modeling method we propose may help evaluate the effectiveness of competing gradient generation schemes. Finally, our analytical work introduces a framework for developing simple design rules of interest to experimentalists working with these devices.

Humidity assay for studying plant-pathogen interactions in miniature controlled discrete humidity environments with good throughput

“…[8][9][10][11][12] These approaches allow for flexible manipulation of chemical concentrations at a small scale, thus facilitating studying many scientifically important biological phenomena, such as chemotaxis and morphogenesis of single cells and multicellular microorganisms. [13][14][15][16][17][18][19] The flow-based method uses an external pumping system to produce stable gradients perpendicular to parallel laminar flows of varying concentrations.…”

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