Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

Since AuNPs by themselves are "blind" with respect to sensing the target, the addition of specific biomolecules to their surfaces is a key step for detecting viruses [37, 38, 40] . Unfortunately, most biomolecules have been reported to be very sensitive to harsh chemical modifications that can adversely affect their reactivity and specificity. Thus, the type of targeting biomolecule and the surface conjugation reaction method applied are crucial and require optimization. Short oligonucleotides and other DNA sequences are physically rigid and more stable than protein biotargeting structures, including antibodies, which usually have several secondary and tertiary conformations that are important for their full, specific interaction with a target molecule. Furthermore, the full reactivity of surface biomolecules via a suitable conjugation reaction is critical and should be retained and confirmed with additional assessment steps before use in virus detection. While the application of traditional conjugation techniques, such as electrostatic adsorption, is still widely reported, it is strongly recommended to be avoided due to the incident loss of conjugated biomolecule activity and large inequality in loading efficiency, which directly result in decreased assay sensitivity and reproducibility [216] . In this regard, AuNPs have an enhanced surface area-to-volume ratio that greatly improves the efficacy of current conjugation techniques, and several directional and controlled conjugation methods based on covalent and noncovalent interactions have been thoroughly described in the literature [9, 32, 35] .