Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

The family Picornaviridae is taxonomically very diverse and has recently been expanded to involve 12 genera: eight are originally identified genera (Aphthovirus, Cardiovirus, Enterovirus, Erbovirus, Hepatovirus, Kobuvirus, Parechovirus, and Teschovirus), and four newly proposed genera (Avihepatovirus, Sapelovirus, Senecavirus, and Tremovirus) [202] . Picornaviruses are spherical, relatively small (22-30 nm) , nonenveloped RNA viruses. Their genome is positive-sense ssRNA that is 7.0-9.5 kb in size and terminally bonded to a noncapsid viral protein (VPg) at its 5' end and to a polyadenylated tail at its 3' end. The expression of this genome produces a single large polyprotein that undergoes a cascade of cleavage and processing reactions to form 10-12 final structural (VP1-4) and nonstructural (2A-C and 3A-D) proteins [203] . Picornaviruses can infect a broad spectrum of hosts, including birds, humans, and other mammals [202, 204] . The genera Enterovirus, Hepatovirus, Parechovirus, Kobuvirus, and Cardiovirus include several important species that affect humans. Particularly, the genus Hepatovirus encompasses HAV, which is the most likely causal agent of acute viral hepatitis in humans. HAV infection is usually asymptomatic and self-limiting, and the related symptoms can be mild or sporadically progress to fulminant hepatic failure [205, 206] . The availability of an effective vaccine against HAV has substantially reduced the number of people who become infected with HAV [207, 208] . However, the ability of this virus to survive harsh environmental conditions and remain in seawater, fresh water, wastewater, and soil for extended periods increases the possibility of outbreaks, especially in developing countries where sanitation is not typically available [205] . The transmission of the virus usually occurs through the consumption of contaminated materials. As such, the virus does not replicate in the environment, water, or foods, and traces of viral contamination are difficult to identify, which remains a challenge for controlling HAV. The need for sensitive assays for HAV remains an urgent public health demand.