A review of the current isothermal amplification techniques: Applications, advantages and disadvantages

Polymerase chain reaction is the most widely used method for DNA amplification for the detection and identification of infectious diseases, genetic disorders and for other research purposes. However, it requires a thermocycling machine to separate the two DNA strands and then amplify the required fragment. Novel developments in molecular biology of DNA synthesis in vivo demonstrate the possibility of amplifying DNA in isothermal temperature without the need of a thermocycling apparatus. DNA polymerase replicates DNA with various accessory proteins. Therefore, with identification of these proteins, we are able to develop new in vitro isothermal DNA amplification methods by mimicking these in vivo mechanisms. There are several isothermal nucleic acid amplifications, such as transcription-mediated amplification or self-sustained sequence replication, nucleic acid sequence-based amplification, signal-mediated amplification of RNA technology, strand displacement amplification, rolling circle amplification, loop-mediated isothermal amplification of DNA, isothermal multiple displacement amplification, helicase-dependent amplification, single-primer isothermal amplification and circular helicase-dependent amplification. In this paper, we reviewed the nucleic acid amplification methods and their applications in molecular biology. We reviewed the best-known isothermal techniques for DNA/RNA amplification. The above information can be used for the application of valuable molecular diagnostic techniques for the detection of infectious agents in small-scale hospital laboratories in the field. With regards to the properties of isothermal DNA/RNA amplification techniques, the design and development of novel rapid molecular tests for application in field may be possible. ABSTRACT Address for correspondence: