Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

HAV detection using AuNPs was accomplished through scanometric and SERS-based assays. Both assays rely on the extensively described virtue of AuNPs to enhance silver staining, thereby allowing the molecular detection of HAV DNA in a microarray chip format (Table 1 and Fig. 6 ). In the scanometric AuNPs modified with anti-biotin IgG are applied to label biotinylated target DNA captured on the PDA chip. After a silver enhancement step, the precipitated silver metal at the surfaces of the AuNPs blocks the light irradiated from above by light-emitting diodes (LEDs) and decreases the resulting photocurrent [89] . (B) Microfluidic bead-based enzyme-AuNP amplification method for the fluorometric detection of HPV. Streptavidin-coated beads are dually functionalized with biotin-electron-rich protein and biotin-DNA capture probes. The captured target DNA first reacts with horseradish peroxidase (HRP)-functionalized AuNP-DNA labels, bringing HRP close to the surface of the microbeads. The oxidation of tyramine-biotin by hydrogen peroxide results in the deposition of multiple biotin moieties onto the surface of the beads. This deposition is markedly increased in the presence of immobilized electron-rich proteins. Streptavidin-labeled quantum dots (QDs) are then allowed to bind to the deposited biotin moieties and display amplified fluorescence signals in relation to the target DNA concentration [98] . detection scheme, AuNP-DNA conjugates are applied as specific detection probes to label target HAV RNA captured by specific VP1 probes on the surface of a microarray chip. A silver metal enhancement step is subsequently used for signal amplification, followed by the visual detection of nucleic acids [79] . In the SERS detection, the captured HAV DNA is labeled by AuNP-DNA probes loaded with the Raman reporter dye Cy3; this approach has been applied as previously described for EBOV and depicted in Fig. 6 of this review [50] . These assays are very simple and can detect target concentrations ranging from 3.37×10 -7 -3.37×10 -8 M, with 100 fM as a limit of detection, which can be superior to the relatively expensive PCR-based approaches currently used for HAV detection and management.