Integrating high-performing electrochemical transducers in lateral flow assay

Abstract

Lateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

Aptamer-based CRISPR-Cas powered diagnostics of diverse biomarkers and small molecule targets

“…Using rolling circle amplification (RCA) and preassembled target-specific aptamer on the surface of MB to elongate ssDNA strands; resulted in very high collateral damage activity. Similarly, to overcome the slow release of acDNA, an assay performed using hybrid DNA for exponential signal improvement; repeated acDNAs enhanced frequency and accessibility to Cas12a/crRNA complex and increased sensitivity [ 58 ]. Using this approach, SARS-CoV-2 RNA was detected to be as low as ~ 42 copies/mL.…”

Electrochemical Affinity Biosensors: Pervasive Devices with Exciting Alliances and Horizons Ahead

“…The versatility of current electrochemical substrates in terms of use (reusable or disposable , ), design, fabrication materials (paper, sustainable, edible, plastic, textile, and polymeric), and properties (superwettable, flexible, and stretchable) should be highlighted. Electrochemical affinity bioassays have also been successfully integrated into microfluidic (Figure b) and lateral flow (eLFA) devices (Figure c). , …”

“…Electrochemical affinity bioassays have also been successfully integrated into microfluidic 25 (Figure 3b) and lateral flow (eLFA) devices (Figure 3c). 26,27 Moreover, advances in microfabrication and microfluidic tecnologies 28 have led to the development of integrated devices able to unify the sample collection, preparation, analysis, and postprocessing (known as "sample-in-answer-out" type of devices 29 ) or able to obtain multiplexed 30,31 and/or multiomic information in a minimally invasive manner.…”

Facilitating Electrochemical Lateral Flow Assay using NFC-Enabled Potentiostat and Nitrocellulose-based Metal Electrodes

“…An alternative strategy to obtain true quantitative outputs is the integration of electrochemical transduction into the LFA strips. 12,13 Printing metal electrodes on nitrocellulose membranes using commercial inks has proven to be challenging however, due to the use of organic solvents in their formulations (needed to dissolve the polymer binder) which damage the delicate membrane. Instead of direct printing of metal inks onto the nitrocellulose membrane, attempts were made to attach external electrodes to the detection area of the LFA.…”