Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

The AuNP-based fluorometric assays developed for H5N1 detection have simply exploited the intense plasmonic-based quenching properties of AuNPs through different detection formats. One of these assays targets the detection of the whole virus particle through a lateral-flow immunoassay format that is similar to that previously described for the detection of HSV-2, as shown in Fig. 11A . In this assay, the virus is first captured on a lateral-flow test strip by pre-immobilized antibodies; then, AuNP-antibody conjugates are applied to label the captured virus particles. After washing, the AuNPs are collected and dissolved to release gold ions that are eventually utilized to quench the fluorescence of QDs in an additional, separate step [58] . In addition, Ganbold et al. have developed a bimodal assay for the fluorometric and SERS detection of viral RNA using AuNPs modified with ssDNA-dye probes [64] . The surface ssDNA-dye probes are weakly adsorbed to the surface of AuNPs by electrostatic interactions, and with the addition of the complementary target DNA, perfectly matched dsDNA forms and desorbs from the surface of AuNPs, resulting in measurable changes in the conjugated dye fluorescence and Raman fingerprint that are more substantial than those resulting from either mismatched dsDNA or ssDNA (Fig. 12A) .