Linearity and dissociative antigen noise analyses of competitive microfluidic heterogeneous immunoadsorption

Presently, microfluidic heterogeneous immunoadsorption (MHI) has been regarded as an effective and efficient on-chip sample preparation method for various clinical diagnoses. In this work, adsorption performances of an electroosmosis flow (EOF)-based competitive MHI under saturated status are studied numerically. Along with the well-known flow and surface reaction control modes, the diffusion control mode specified in the fluidic configuration is scrutinized to characterize the MHI performance. The numerical results indicate that only in the surface reaction or the diffusion control mode can saturated EOF-based MHI obtain a linear dose-response along with a perfect assay signal without so-called dissociative antigen noise. Considering the tunable assay time and realizable flow velocity required by chip applications, the diffusion controlled MHI is recommended in this work.