Polymerase chain reactions (PCRs) were carried out on as many as four DNA s
amples at a time on a microchip device. The PCR products were then analyzed
, either individually or together on the same device, by microchip gel elec
trophoresis. A standard PCR protocol was used to amplify 199- and 500-base
pair (bp) regions of bacteriophage lambda DNA and 346- and 410-bp regions o
f E. coli genomic and plasmid DNAs, respectively. Thermal lysis of the bact
eria was integrated into the PCR cycle. A product sizing medium, poly(dimet
hylacrylamide), and an intercalating dye for fluorescence detection were us
ed in the electrophoretic analysis of the products. PCR product sizes were
determined by coelectrophoresis with marker DNA.