Numerical Modeling for Sensitive and Rapid Molecular Detection by Membrane-Based Immunosensors

Rapid, simple, and sensitive point-of-care testing (POCT) has attracted attention in recent years due to its excellent potential for early disease diagnosis and health monitoring. The flow-through biosensor design is a candidate for POCT that utilizes the small-sized pores of a porous membrane as a recognition space where it emits a signal comparable to that of a conventional enzyme-linked immunosorbent assay within 35 min of detection time. In this paper, we present a numerical model for this immunosensing technology to systematically design an improved recognition system. The model considers mass transfer into the pore (convection and diffusion), the kinetics between the immobilized receptor and the target molecule, and the flow conditions, successfully leading to a bottleneck step (capture of secondary antibody) in sandwich-type detection. Our simulation results also show that this problem can be solved by adopting both appropriate receptors and analytical conditions. Eventually, the requirements to achieve the sensitivity required for POCT were fulfilled, which will allow for further development of immunosensing devices for disease detection.