Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

AuNP-based colorimetric assays have been developed for IAV detection through four main detection schemes: 1) The first scheme involves the application of AuNPs conjugated with anti-digoxigenin as colorimetric labels to detect the target viral DNA premodified with digoxigenin and electrophoresed through a membrane-based lateral-flow technique [66] . 2) The second scheme is simply based on the electrostatic interactions between the negatively charged phosphate groups of the target DNA amplified with LAMP and the positively charged CTAB bilayer on AuNRs, resulting in the aggregation of AuNRs and a color change from red to purple [67] . 3) The third scheme relies on a magnetic-based hydroquinone oxidation reaction involving two metal NP bioconjugates: IAV-specific pentabody-MNPs as capture probes and anti-AIV monoclonal antibody-AuNPs as detection probes. In the presence of virus particles, an immunocomplex forms and is separated by a magnetic field; after washing, AuNPs in the separated complex act to catalyze the oxidation of hydroquinone, which is detected optically in correlation with the AIV sample concentration [92] . 4) The fourth scheme relies on the peroxidase-like catalytic activity of Au NP films and colloidal AuNPs toward TMB-H2O2 mixtures. The virus is captured on a 96-well plate modified with AuNP film biofunctionalized with HA antibody. Then it is labeled with AuNPs modified with NA antibody for signal generation. TMB-H 2 O 2 is added, and rapid color changes are observed because of the oxidation of peroxidase substrate TMB. Using H1N1, the response of the developed assay was linear in the range from 10 pg/mL to 10 μg/mL and the limit of detection was 50.5 pg/mL, while with H3N2, the optical density of the developed color was dependent on the virus concentration in the range of 10-50,000 PFU/mL and the limit of detection was 24.3 PFU/mL [22] .