In
immunobead-based assays, micro/nanobeads are functionalized
with antibodies to capture the target analytes, which can significantly
improve the assay’s performance. The immunobead-based assays
have been recently combined with microfluidic mixing devices and customized
for a variety of applications. However, device design and process
optimization to achieve the best performance remain a substantial
technological challenge. Here, we introduce a computational model
that enables the rational design and optimization of the immunobead-based
assay in a microfluidic mixing channel. We use numerical methods to
examine the effect of the flow rates, channel geometry, bead’s
trajectory, and the analyte and reagent characteristics on the efficiency
of analyte capture on the surface of microbeads. This model accounts
for different bead movements inside the microchannel, with the goal
of simulating an actual active binding environment. The model is further
validated experimentally where different microfluidic channels are
tested to capture the target analytes. Our experimental results are
shown to meet theoretical predictions. While the model is demonstrated
here for the analysis of IgG capture in simple and herringbone-structured
microchannels, it can be readily adapted to a broad range of target
molecules and different device designs.