Screening antibodies for paper-based zika and dengue assays using microfluidic resistive pulse sensing

PROJECT ABSTRACT Lateral flow assays are low-cost, paper based assays that can provide readouts within minutes. They have shown great promise as point of care rapid diagnostic tests (RDTs) for many hemorrhagic viral fevers such as dengue and zika because they are operable by non-experts, robust, and portable. A fluid is added to a test and wicks through, and if an antigen is present, a color appears at the test line due to the accumulation of gold nanoparticle (NP) antibody conjugates. While LFAs have proven utility in the field, they rely on antibody pairs specific for the biomarker of interest, so for every new disease a pair of antibodies must be determined. Arriving at a functional configuration of antibodies and NPs is labor intensive and expensive. In particular, each of the antibodies must be run in pairs and tested against each antigen in a paper strip format, as ELISA cannot predict sandwich immunoassay behavior. This presents major bottleneck in both time and required antibody samples, so any means to improve this process would significantly reduce the time and cost to produce RDTs for emerging outbreaks. Here, we will investigate the use of microfluidic resistive pulse sensing (MRPS) to help streamline the antibody screening method for a multiplexed dengue and zika test. MRPS is a highly sensitive technique that measures the size of a particle by its transport properties through a pore which has a voltage applied across it. MRPS requires very small sample volume and has the sensitivity to be able to measure when antigens bind to a NP-antibody complex. Thus, it has the potential to reduce sample requirements for screening and designing antibody pairs in an LFA. This could potentially reduce the amount of antibodies in immunoassay development, ultimately reducing both development costs and time. Benefits of the work will make immunoprobe design more efficient and would reduce the antibody amounts in screening for LFAs tests faster and at lower cost. Expediting immunoprobe optimization would also streamline assay development and improve rapid response to infectious disease outbreaks.