Ultrasensitive lateral-flow assays via plasmonically active antibody-conjugated fluorescent nanoparticles

• DOI: 10.1038/s41551-022-01001-1
• Publication Date: 2023-02-02T17:04:52Z
• Authors: Rohit Gupta; Prashant Gupta; Sean Wang; Artem Melnykov; Qisheng Jiang; Anushree Seth; Zheyu Wang; Jeremiah J. Morri...; Ige George; Sumanth Gandra; Pratik Sinha; Gregory A. Storch; Bijal A. Parikh; Guy M. Genin; Srikanth Singamaneni
• Keywords: 0301 basic medicine; 03 medical and health sciences; 3. Good health

Lateral-flow assays (LFAs) are rapid and inexpensive, yet they are nearly 1,000-fold less sensitive than laboratory-based tests. Here we show that plasmonically active antibody-conjugated fluorescent gold nanorods can make conventional LFAs ultrasensitive. With sample-to-answer times within 20 min, plasmonically enhanced LFAs read out via a standard benchtop fluorescence scanner attained about 30-fold improvements in dynamic range and in detection limits over 4-h-long gold-standard enzyme-linked immunosorbent assays, and achieved 95% clinical sensitivity and 100% specificity for antibodies in plasma and for antigens in nasopharyngeal swabs from individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Comparable improvements in the assay's performance can also be achieved via an inexpensive portable scanner, as we show for the detection of interleukin-6 in human serum samples and of the nucleocapsid protein of SARS-CoV-2 in nasopharyngeal samples. Plasmonically enhanced LFAs outperform standard laboratory tests in sensitivity, speed, dynamic range, ease of use and cost, and may provide advantages in point-of-care diagnostics.