Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

In the immunological detection of HCV, AuNPs dually modified with capturing antibodies and barcoding DNA, similar to those described for the immuno-PCR technique, in combination with magnetic NP (MNP)-antibody conjugates, have been applied to capture and separate the target antigen. Subsequently, the barcode DNA is further allowed to act as a bridge, guiding the formation of a multilayer of AuNP-DNA probes over the surface of a nanogap electrode (Fig. 7A) . The formation of such barcode DNA-guided AuNP multilayers significantly increases the detected electrical current and is utilized to quantitatively measure the target HCV antigen concentration in applied solutions. The results of this immunoassay indicate a detection limit of 1 pg/µL [69] . In a similar protocol, the barcoding DNA was further applied to HCV core antigen detection based on an enzyme to release the barcode DNAs to be quantified with RT-PCR. This assay showed a detection limit of 1 fg/mL, which is one magnitude greater than the standard ELISA (2 ng/mL) [14] .