Micro-PCR devices

Keywords Continuous flow PCR DNA analysis DNA microarrays Genetic analysis Integrated microsystems Microcapillary electrophoresis Microfluidics Micro-PCR devices Solid-phase extraction... 

Multiple PCR chambers have been fabricated on a single microfluidic chip and explored for high throughput PCRs [78-83]. An example of a multichamber micro-PCR device, the micro-DNA amplification and analysis device, (p-DAAD) consisted of 16p-DAADs in parallel with each p-DAAD consisting of four microreactors fabricated on a 4" silicon wafer (see Fig. 4). Multichamber micro-PCR devices [84] have been demonstrated for DNA amplifications of five gene sequences related to E. coli from three different DNA templates and detected by TaqMan chemistry with a limit of detection (LOD) of 0.4 copies of target DNA. 

Conventional PCR instruments typically utilize contact heating, which involves a metal heating block in contact with the sample container, to cycle the temperature of the PCR solution that is held within a thin-walled polypropylene tube. In spite of their large thermal mass and slow temperature ramping rates, metallic heating blocks and Peltier-based thermo-electric (TE) ceramic heating blocks are widely applied in micro-PCR devices [69, 84, 87, 123-128]. To achieve fast thermal transition, two [8, 98, 123, 129] or more TE devices can be coupled to thermally cycle the PCR solution, and a total of six TE devices have been used in a portable... 

It is important to note that the thermal-cycling rate is limited by the thermal mass of the heating element itself and of the entire micro-PCR device as well. Moreover, in the case of an external contact element, localized heating is ultimately limited in terms of lateral resolution by the thermal conductivity of the substrate material. In the case of on-chip integrated heaters, these devices still require tedious and complicated micromanufacturing processes, which restrict the flexibility to reconfigure the PCR design [133]. 

Chou, C.F., Changrani, R., Roberts, R, Sadler, D., Lin, S., Mulholland, A., Swami, N., Terbrueggen, R., Zenhausern, F., A miniaturized cyclic PCR device. Micro Total Analysis Systems, Proceedings 5th p7AS Symposium, Monterey, CA, Oct. 21-25, 2001, 151-152. 

Other extensions that have been made include the construction of a biochip in which a reverse transcription PCRprocess can be carried out [384] and the integration of PCR with capillary electrophoresis [385], DNA microarray hybridization [386] and sample preparation [387,388]. The speed of analysis, the ease of integrating different functions and the relative low costs of micro-PCR production are important advantages of the miniaturized PCR technique that suggest that this bioorganic microreactor device will be thoroughly implemented in many analytical labs. 

A. Reichert, J. Felbel, M. Kielpinski, M. Urban, B. Steinbrecht, and T. Henkel, Micro Flow-Through Thermocycler with Simple Meandering Chaimel with Symmetric Temperature Zones for Disposable PCR-Devices in Microscope Slide Format, J. Bionic. Eng., vol. 5, pp. 291-298, 2008. 

Woolley AT, Hadley D, Landre P, deMello AJ, Mathies RA, Northrup MA. Functional integration of PCR amplification and capillary electrophoresis in a micro-fabricated DNA analysis device. Anal Chem 1996 68 4081-4086. 

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