A DNA biochip for on-the-spot multiplexed pathogen identification

Yeung, Siu-Wai; Lee, Thomas Ming-Hung; Cai, Hong; Hsing, I-Ming

Another attractive feature of this microdevice is multiplexing. By constructing an electrode array, it is possible to identify several species in a single run. The results for the detection of the two model species are presented in Figure 6 . If the sample contains E.coli cells only, there is a significant increase in the analytical signal (silver metal stripping time) for the E.coli detection capture probefunctionalized electrode while that for the B.subtilis remains the same as the background signal. When the sample contains Figure 5 . A calibration plot of the sample-to-background ratio against the logarithmic number of E.coli cells in the sample. In our four working electrode design, the silver stripping time to reach a potential of +0.65 V (versus Pt pseudo-reference electrode) for the E.coli detection capture probemodified electrodes was taken as the sample signal whereas that for the B.subtilis detection capture probe-modified electrodes was taken as the background signal. Note that the number of cells stated was the amount being introduced into the microchamber.