Flow Confinement Enhancement of Heterogeneous Immunoassays in Microfluidics

This paper aims to enhance the analyte transport toward the sensing area and to enhance biosensors performances. A microchannel-based flow confinement method for rapid delivery of small sample volumes to sensor surface is described. To confine the flow, a sample flow is joined with a perpendicular makeup flow and is confined into a thin layer above the reaction surface. The numerical simulation of the confinement effect on the binding reaction is performed using the finite-element method. The influence of several parameters on the binding reaction is provided, such as the average flow velocity at the inlet of the microchannel and the velocity of the confinement flow, the characteristics of the flow confinement. The numerical results reveal that the flow confinement enhances mass transport of analytes and increase its velocity. The obtained results could be exploited in flow injection experiments for low volume.