Polymerase chain reaction microchip

Chen, J., M. Wabuyele, H. Chen, D. Patterson, M. Hupert, H. Shadpour, D. Nikitopoulos, and S.A. Soper. Electrokinetically synchronized polymerase chain reaction microchip fabricated in polycarbonate. Anal Chem. 2005, 77(2), 658-666... 

Zhou et al. [175] described the determination of severe acute respiratory syndrome (SARS) coronavirus by a microfluidic chip system. The unit included an LIF microfluidic chip analyzer, a glass microchip for both PCR and capillary electrophoresis, a chip thermal cycler based on dual Peltier thermoelectric elements, a reverse transcription-polymerase chain reaction (RT-PCR) SARS diagnostic kit, and a DNA electrophoretic sizing kit. According to the authors, the system allowed efficient DNA amplification of the SARS coronavirus followed by electrophoretic sizing and detection on the same chip. 

The polymerase chain reaction is the prevalent method for DNA amplification. Much effort has been made to integrate PCR chambers on microchips to carry out amplifications of DNA molecules prior to their analysis. For instance, PCR was first achieved on a Si-based reaction chamber (25 or 50 pL) integrated with a polysilicon thin-film (2500-A-thick) heater for the amplification of the GAG gene sequence (142 bp) of HIV (cloned in bacteriophage M13) [997]. 

Giordano, B.C., Ferrance, J., Swedberg, S., Huhmer, A.F.R., Landers, J.P., Polymerase chain reaction in polymeric microchips DNA amplification in less than 240 seconds. Anal. Biochem. 2001, 291(1), 124-132. 

Cheng, J., Waters, L.C., Fortina, P., Hvichia, G., Jacobson, S.C., Ramsey, J.M., Kricka, L.J., Wilding, P., Degenerate oligonucleotide primed-polymerase chain reaction and capillary electrophoretic analysis of human DNA on microchip-based devices. Anal. Biochem. 1998, 257(2), 101-106. 

Sung, W.C., Lee, G.B., Tzeng, C.C., Chen, S.H., Plastic microchip electrophoresis for genetic screening The analysis of polymerase chain reactions products of fragile X (CGG)n alleles. Electrophoresis 2001, 22, 1188-1193. 

While a wide range of opportunities exist, such as environmental, clinical, and trace analysis, the principal application for labs-on-a-chip is in the analysis of biological samples. The miniaturized dimensions allow extremely small sample volumes to be analyzed, and a microchip format can allow chemical reaction, mixing, sample manipulation, and multiplexing to be performed. Single-cell analysis, immunoassays, protein and peptide separations, DNA analysis and sequencing, and polymerase chain reactions have all been performed on microchip devices [48]. 

Detection with a microchip is primarily through LIF, since this is eashy implemented with the planar configuration of the microchip (Figure 5-10). Limits of detection for fluorescein-like fluors have been easily demonstrated at the 10 M level and pushed as low as 10 M—a mass detection limit of a few hundred molecules. This allows for detection, for example, of polymerase chain reaction (PCR)-amplified DNA fragments at a level that competes with P-autoradiography jffom Southern blots. Typical microchip separation times are around 50 to 200 seconds. 

Giordano BC, Copeland ER, Landers JP. Towards dynamic coating of glass microchip chambers for amplifying DNA via the polymerase chain reaction. Electrophoresis 2001 22 334-40. 

Several examples of work in this field have been reported for multiple-sample polymerase chain reaction (PCR) amplifications (464 166) and electrophoretic analysis in a microchip. In one example, the PCR products from four DNA samples were analyzed by microchip gel electrophoresis (466). The ability to analyze a large number of DNA samples in this format was presented. Run-to-run reproducibility in the sizing microchip was very good percent relative standard deviation n = 8 for migration times was better than 0.3%. The accuracy of the 500-base-pair sizing was greater than 98% (466). 

With this chip, DNA can be concentrated by a factor of up to two orders of magnitude. Khandurina et al. also reported an integrated system for polymerase chain reaction (PCR)-based analysis on a microchip with this preconcentration technique. The chip layout was similar to that depicted in Figure 50.30, with an additional Peltier thermoelectric element integrated for the DNA amplification. With this chip, a 25-fold preconcentration of the DNA sample due to the semipermeable silicate membrane was observed. 

The polymerase chain reaction (PCR) is the most widely used technique for oligonucleotide synthesis. Microchips/microdevices for PCR are studied extensively, and thus great progress has been made in the development and scope of microchip components of microchip-based PCR analyzers such as on-chip micromachining (fabrication, bonding, and sealing), choice of... 

Alternatively, microchip technologies offer other platforms for HTS such as microarrays and microfluidic devices. Microarrays allow the simultaneous analysis of thousands of parameters within a single experiment and for this reason have become cracial tools in drug discovery and life sciences research. They consist of immobilized biomolecules spatially addressed on planar surfaces, microchannels or microweUs, or an array of beads immobilized with different biomolecules. Biomolecules commonly immobilized on microarrays include oligonucleotides, polymerase chain reaction (PCR) products, proteins, lipids, peptides, and carbohydrates. Currently, in situ synthesized microarrays can be purchased or... 

Sun Y, M.V.D S, Kwok YC, Nguyen NT (2008) Continuous flow polymerase chain reaction using a hybrid PMMA-PC microchip with improved heat tolerance. Sens. Actuators B, Vol. 130, 836-841. 

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