| Abstract
| - An integrated plastic microfluidic device was designed andfabricated for bacterial detection and identification. Thedevice, made from poly(cyclic olefin) with integratedgraphite ink electrodes and photopatterned gel domains,accomplishes DNA amplification, microfluidic valving,sample injection, on-column labeling, and separation.Polymerase chain reaction (PCR) is conducted in achannel reactor containing a volume as small as 29 nL;thermal cycling utilizes screen-printed graphite ink resistors. In situ gel polymerization was employed to form localmicrofluidic valves that minimize convective flow of thePCR mixture into other regions. After PCR, amplicons(products) are electrokinetically injected through the gelvalve, followed by on-chip electrophoretic separation.An intercalating dye is admixed to label the amplicons;they are detected using laser-induced fluorescence. Twomodel bacteria, Escherichia coli O157 and Salmonellatyphimurium, were chosen to demonstrate bacterialdetection and identification based on amplification ofseveral of their unique DNA sequences. The limit ofdetection is about six copies of target DNA.
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