Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

Molecular techniques are attracting more interest and have found an increasing number of applications in virus detection. The discovery of the genetic enzyme systems involved in the cellular machinery of nucleic acid replication and the stunning invention of an in vitro nucleic acid amplification system, commonly called PCR, by Mullis in the early 1980s, opened new frontiers in nucleic acid-based detection [33] . In addition, the known high specificity of nucleic acid hybridization and the absolute availability of its synthesis and modification guided the development of many Figure 1 . The onset of nanotechnology in virus detection applications compared with the development of the most common virus detection techniques. Cell culture and electron microscopy techniques that are now commonly applied in the direct testing for and detection of viruses were discovered in the mid-20th century [25] . Then, different serological and molecular techniques were developed. The serological detection of viruses with immunoassays was first reported in 1970: a radioimmunoassay was applied for the detection of the Australia antigen, later called hepatitis B virus surface antigen [218] . PCR was discovered in the 1980s and first reported in virus detection in 1988 for acquired immune deficiency syndrome detection [219] . Later, many molecular techniques, including amplification-and nonamplification-based techniques, were reported in virus detection. The concept of nanotechnology was envisioned as early as 1959 by the renowned physicist Richard Feynman [36] . However, nanotechnology was only applied to virus detection in 1997, when gold nanoparticles were employed for the detection of single-copy human papillomavirus [39] . Nanotechnology has recently come to represent one of the most outstanding trends in virus detection and diagnosis via the wide variety of assays described in this review. detection and genotyping techniques known for the rapid and specific detection of viruses. These techniques can be classified as amplification-or nonamplification-based molecular detection techniques. Amplification-based molecular techniques usually employ one or more forms of nucleic acid amplification to allow the indirect detection of the target virus. These techniques represent the majority of molecular techniques applied in virus detection and include various types of target amplification techniques (e.g., PCR, loop-mediated isothermal amplification (LAMP), transcription-mediated amplification, and nucleic acid sequence-based amplification), signal amplification techniques (e.g., branched DNA and hybrid capture), and probe amplification techniques (e.g., ligase chain reaction and strand-displacement amplification). Nonamplification-based techniques are mainly applied to the direct testing for the presence of a specific virus in clinical samples (e.g., in situ hybridization, southern blot hybridization, and dot blot hybridization).