Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

AuNP-based scanometric assays for detecting AIV are mainly performed using the well-described AuNP-promoted metal staining protocol shown in Fig. 12D . In this protocol, the target nucleic acid is recaptured on the surface of glass chips modified with specific capture DNA probes [86] . Then, the captured probes are labeled with AuNPs either modified with specific DNA probes or with the renowned dsDNA intercalator daunorubicin [83] to mediate the metal staining. Following this labeling step with AuNP probes, the presence of the target nucleic acids is visually determined with an additional silver-or gold-staining step. Specific DNA aptamers immobilized on a gold electrode (GE) modified with a layer of multiwall carbon nanotubes (MWCNTs), polypyrrole nanowires (PPNWs) and AuNPs are collectively applied as an electrochemical platform for the detection of DNA hybridization using DPV [71] . (C) Impedimetric electrochemical assay using streptavidin-AuNPs probes. The direct/sandwich hybridization of biotinylated target DNA with capture probes immobilized on the surface of a screen-printed electrode (SPE) and additional conjugation with streptavidin-AuNPs results in impedimetric signal enhancement [70] . (D) Label-free scanometric detection using positively charged AuNPs. The electrostatic interaction between positively charged AuNPs and negatively charged DNA is utilized to visualize the double-stranded (ds)DNA formed by the hybridization of single-stranded probe DNA and complementary target DNA on the array of chips through AuNP-mediated metal staining [83, 86, 87] .