Miniaturized PCR chips for nucleic acid amplification and analysis: latest advances and future trends

Zhang, Chunsun; Xing, Da

In many cases, amplification is indispensable for the analysis of nucleic acids. Currently, nucleic acid amplification methods include but are not limited to polymerase chain reaction (PCR) (1), strand-displacement amplification (SDA), nucleic acid sequence-based amplification (NASBA), rolling-circle amplification (RCA) and the Q b replicase reaction. Among these methods, PCR has been the most popular due to its simplicity; however Peltier effect or metal-block-based PCR system are characterized by high thermal mass, large reaction volume and thus slow heating/cooling rates. The PCR speed can be improved by increasing the heat transfer rate or decreasing the thermal mass. With the advent of micro-electromechanical-systems (MEMS) technology, the development of miniaturized PCR chips becomes possible (2, 3) . The miniaturization of PCR devices offers several advantages such as short assay time, low reagent consumption and rapid heating/cooling rates, as well as great potential of integrating multiple processing modules to reduce size and power consumption. The number of publications on PCR chips has grown rapidly recently, and the articles are spread over a large number of journals. The development of PCR microchips has been discussed in recent reviews (2) (3) (4) . In this article, we will review the latest advances and future trends based on literature published since January 2005. In addition, we will also discuss some practical issues related to the development of PCR chips. As a supplement to this review, the reader may wish to refer to several reviews of general microfluidic technologies (5) (6) (7) (8) (9) .