Dual-mode and multiplex lateral flow immunoassay: a powerful technique for simultaneous screening of respiratory viruses

Abstract

Respiratory viral infectious usually exhibit similar clinical symptoms, making a great challenge for their accurate diagnostic in early stages. Herein, we developed a dual-mode and multiplex lateral flow immunoassay (LFIA), in which near-infrared (NIR)-responsive Janus Aushell-Fe3O4 nanoparticles (NPs) were synthesized as new reporters for highly sensitive colorimetric/photothermal detection of H3N2 influenza and SARS-CoV-2 viruses in a single assay. The Janus Aushell-Fe3O4 well combined the NIR responsiveness and high molar absorption coefficient of Aushell and magnetic properties of Fe3O4. In the detection, two test (T) lines were arranged on the strip, which could capture corresponding virus antigen-Aushell-Fe3O4 complexes, forming color bands. Hence, according to the position of color bands and their photothermal signals, the type and amount of virus could be quickly determined. The naked-eye limits of detection (LODs) for H3N2 and SARS-CoV-2 were both 50ng/mL. The photothermal quantitative ranges were from 10 to 106pg/mL with LODs of 2pg/mL (H3N2) and 7pg/mL (SARS-CoV-2), which were nearly 10000 times lower than naked-eye detection. Moreover, this multiplex LFIA showed good specificity and anti-interference ability, which was applied to complex samples with satisfactory results. Thus, this Aushell-Fe3O4 LFIA showed great application potential in rapid virus screening and early detection.