(H-315) Glowstick-Inspired Lateral Flow Immunoassays: A Smartphone-Readable Biomarker Detection Platform for Highly Sensitive, Multiplexable, Rapid Tests

Introduction:: The COVID-19 pandemic and recent societal trends have driven increased demand for point-of-care (POC) screening tests, such as lateral flow assays (LFAs), emphasizing the necessity for sensitive and cost-effective POC diagnostic platforms. Conventional LFAs utilizing colorimetric gold or latex nanoparticles, however, exhibit limited analytical sensitivity. More-sensitive LFAs employing fluorescent light-emitting reporters necessitate complex instrumentation for excitation and emission detection, negating the simplicity of LFAs.

Materials and Methods:: In this study, we introduce a novel LFA platform that uses standard commercial fluorescent nanoparticles in a new way. Optical excitation is replaced by chemical excitation using the peroxyoxalate-based chemistry of affordable, shelf-stable glowsticks. The one-step chemi-excitation of fluorescent particles generates visible light readable by a smartphone or small portable reader, thus increasing LFA sensitivity while maintaining simplicity and cost-effectiveness.

Results, Conclusions, and Discussions:: The novel "glow" LFA detected the common model analyte human chorionic gonadotropin (hCG) with a limit of detection of 39 pg/mL, demonstrating over ten times higher sensitivity compared to standard gold nanoparticles using the same antibodies. We also demonstrated the detection of SARS-CoV-2 nucleoprotein at 100 pg/mL in nasal swab extracts. Several different fluorescent dyes can be simultaneously chemi-excited by a single glow reagent, enabling color multiplexing on a single LFA using a standard RGB smartphone camera. We demonstrated the detection of three analytes on a single LFA test line using red, green, and blue fluorescent reporter particles. Consequently, the glow LFA presents a promising platform for sensitive, multiplexed detection of three or more analytes on a single LFA strip.

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