1. Thermometric lateral flow immunoassay with colored latex beads as reporters for COVID-19 testing.
- Author
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Azuma T, Hui YY, Chen OY, Wang YL, and Chang HC
- Subjects
- Humans, Immunoassay instrumentation, Microscopy, Electron, Scanning, Thermometry methods, COVID-19 diagnosis, COVID-19 Testing methods, Immunoassay methods, Microspheres
- Abstract
Temperature sensing is a promising method of enhancing the detection sensitivity of lateral flow immunoassay (LFIA) for point-of-care testing. A temperature increase of more than 100 °C can be readily achieved by photoexcitation of reporters like gold nanoparticles (GNPs) or colored latex beads (CLBs) on LFIA strips with a laser power below 100 mW. Despite its promise, processes involved in the photothermal detection have not yet been well-characterized. Here, we provide a fundamental understanding of this thermometric assay using non-fluorescent CLBs as the reporters deposited on nitrocellulose membrane. From a measurement for the dependence of temperature rises on the number density of membrane-bound CLBs, we found a 1.3-fold (and 3.2-fold) enhancement of the light absorption by red (and black) latex beads at 520 nm. The enhancement was attributed to the multiple scattering of light in this highly porous medium, a mechanism that could make a significant impact on the sensitivity improvement of LFIA. The limit of detection was measured to be 1 × 10
5 particles/mm2 . In line with previous studies using GNPs as the reporters, the CLB-based thermometric assay provides a 10× higher sensitivity than color visualization. We demonstrated a practical use of this thermometric immunoassay with rapid antigen tests for COVID-19., (© 2022. The Author(s).)- Published
- 2022
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