Computational modelling of a competitive immunoassay in lateral flow diagnostic devices†

Abstract

Competitive immunoassays are important diagnostic assays for the detection of small molecules such as vitamins, minerals, or some hormones. Although these assays are traditionally used to quantify small molecules, they are not extensively integrated with the paper-based devices. Numerical prototyping of these assays would be of paramount importance as it can help prior design of the devices, and therefore can reduce the time and resources needed. In this work, we are the first ones to present a thorough analysis of the computational model of the paper-based competitive immunoassay. The governing physics along with the pertinent boundary conditions coupled with the reactions both at the test line and control lines were considered to model this system. Furthermore, the performance of the device was evaluated through a simpler scaling analysis. Three important non-dimensional parameters were identified as T/C ratio, Pe, and Da to design such paper-based devices, and a design framework was presented to the readers. This opens up avenues for researchers to gain prior knowledge on their device performances. © 2023 The Author(s).