Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

The family Retroviridae is broadly classified into 7 genera (Alpharetrovirus, Betaretrovirus, Deltaretrovirus, Epsilonretrovirus, Gammaretrovirus, Lentivirus, and Spumavirus), which include nearly 51 viruses [209] . Retroviruses are spherical, small (80-100 nm), enveloped RNA viruses. Their viral genome is typically bipartite and composed of two positive-sense ssRNA molecules (10 kb in total length). They comprise 4 major genes that encode the different structural and nonstructural proteins of the virus: gag encodes the large protein form matrix, capsid, and nucleocapsid; pro encodes the protease enzyme; pol encodes the reverse transcriptase and integrase enzymes; and env encodes the envelope glycoproteins and transmembrane proteins [209] [210] [211] . Retroviruses infect a wide variety of vertebrates, including humans. Their infection in humans is usually very serious and can potentially cause oncogenesis and variable hematopoietic and neurological conditions. Among retroviruses, HIV is a well-known, formidable human pathogen responsible for the most devastating viral pandemic that has ever occurred in human history [212] . HIV infection is usually correlated with the progression of what is clinically called AIDS, in which the immune system is harshly destroyed, and the entire body becomes vulnerable to terrible, life-threatening opportunistic infections and cancers. People with AIDS also suffer from other systemic symptoms, such as fevers, sweats, swollen glands, chills, weakness, and weight loss [213] . Currently, there is no effective vaccine against HIV, and most of the treatment strategies rely on using antiretroviral drugs, which in most cases maintain the viral load at low levels to prevent the formation of acute HIV infection rather than cure the virus [214] . Therefore, the accurate detection of HIV is a key determinant for monitoring HIV treatment and reducing its transmission and dissemination.