Micro-polymerase chain reaction for point-of-care detection and beyond: a review microfluidics and nanofluidics

Miniaturization of biological and chemical analytical devices with microelectromechanical systems (MEMS) technology is important for medical diagnosis, microbial recognition, and other biological analysis. Current or emerging infectious diseases increase the need for point-of-care testing (POCT) to increase timely diagnosis and treatment. Among the various nucleic acid amplification methods, polymerase chain reaction (PCR) has been the most used method due to its simplicity. MEMS and microfluidic technologies enable PCR processes to be miniaturized in a chip. A miniaturized microfluidic chip is a small device that can limit and flow a specific volume of fluid into micro-sized channels. Microfluidic chip has potential benefits such as speed, cost, portability, efficiency, and automation. In addition to these benefits, multifunctional POCT PCR devices based on microfluidics technology can help with clinical diagnosis in underdeveloped nations that need a centralized health care system. In this review, conventional PCR method and the recent advances in microfluidic PCR amplification technologies, including its usage for POCT, are discussed. Current studies in commercialization of microfluidic PCR devices are presented. POCT has become very important during the Coronavirus disease (COVID-19) epidemic; therefore, the applications that evolved with combined use of POCT, PCR, and microfluidics during the COVID-19 pandemic were also covered.