Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

This assay has additional benefits beyond its high specificity and sensitivity that reach down to 20 fM of the target RNA. Because a very large number of probes can be designed based on using different Raman tags, this assay can be readily adapted for multiplex detection, allowing the simultaneous detection of different diagnostic targets of the same virus or even completely different viruses. Furthermore, it does not require DNA amplification and eliminates the need for specific thermal cyclic equipment. In addition, the capability for bimodal detection simplifies evaluation of the results, as the output can be positive/negative either by traditional scanner systems or by SERS when the probes are labeled with Raman dyes. Such simplicity based on bimodal detection without the need for complicated thermal amplification equipment, multiplexing, and high sensitivity supports the application of this technique for EBOV, which is very contagious and usually necessitates the detection of several targets. It is a chip-based detection scheme in which the target DNA is captured by immobilized, specific DNA oligonucleotides and then directly labeled by AuNP-DNA probes, followed by silver enhancement. The AuNPs enhance the surface area available for silver deposition and DNA immobilization to achieve highly sensitive scanometric detection signals. Modification of the AuNP probes with Cy3 allows the additional SERS-based detection of target DNA. This scheme has been reported for the detection of a wide range of viral nucleic acids, including those of HCV, HBV, and HAV, which belong to different virus groups [50] . Furthermore, the scanometric detection reported in this scheme has been considered a universal step in other detection schemes described for other viruses, such as HEV [82] and HIV [81, 84] .