Fig. 7

Examples of metallic nanoparticle-based strategies for diagnosis of respiratory viruses. A A schematic of the ‘naked-eye’ diagnosis of SARS-CoV-2 through proper design of ASO-capped gold nanoparticles (AuNPs). Reprinted from [148] with permission from the American Chemical Society. B—a Transmission electron microscopy (TEM) of ASO-functionalized AuNPs, (b) TEM image of the individual ASO-functionalized AuNPs, c–f TEM images of ASO functionalized AuNPs after addition of SARS-CoV-2 RNA. Reproduced from [148] with permission from the American Chemical Society. C Schematic of the preparation of a diagnostic system for SARS-CoV-2, influenza B and MERS-CoV viruses Reprinted from [149]. D—a Schematic of a point-of‐care lateral flow immunoassay for rapid detection of SARS‐CoV‐2 IgM‐IgG antibodies. b Schematic on the test results. C, control line; G, IgG line; M, IgM line. Reproduced from [155] with permission from Wiley. E Schematic of DNA-AgNCs platform for virus detection through fluorescent readouts based on fluorescence enhancement (turn on), quenching (turn off), or color shifts. Reprinted from [157] with permission from the American Chemical Society. F Schematic of a two-dimensional array of Au@Ag core-shell nanoparticles for direct immunoassay of influenza A virus. Reprinted from [161] with permission from the Royal Society of Chemistry. IgG immunoglobulin G, IgM immunoglobulin M, AgNCs silver nanoclusters, SARS‐CoV‐2 severe acute respiratory syndrome coronavirus 2, EDC 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, NHS N-hydroxysuccinimide, rt room temperature, MHDA 16-mercaptohexadecanoic acid