Study of capture efficiency utilizing passive mixing in heterogeneous microfluidic immunosensors

Abstract

The role of 3-dimensional (3-D) geometries in facilitating surface reactions in microchannels is the subject of the present work. 3-D microfluidic immunosensor geometries inspired from the design of packed bed columns, utilizing splitting and recombination of flows in improving the transport in flow heterogeneous microfluidic immunosensors, were studied systematically. First, the effect of the passive mixing on the antigen capture was tested experimentally using prostate specific antigen (PSA) and anti-PSA and validated using numerical studies. Subsequently, numerical studies on the effects of geometrical parameters like the height and width of the microchannel, the height and width of the grooves, number of groove sets, the ratio of the heights of the grooves and the microchannel etc., on the antigen capture were conducted. The Sherwood number (Sh) and Peclet number (Pe) were used to explain the mass transfer. Finally, the optimum Peclet number (Pe∼x223C 3400) was found, having a maximum figure of merit ratio for the grooved to the ungrooved microchannels Correlations were also obtained between the average surface concentration and the geometrical parameters. The paper presents novel scientific results which are useful for designing efficient heterogeneous immunosensors.