MicroChannel DNA Hybridization

Four spots of DNA probes were applied in a PMMA microchannel (500 pm wide, 50 pm deep). This is intended for detection of low-abundant point mutation in the K-ras gene, which is diagnostic for colorectal cancer. Aminated 24-mer DNA probes were immobilized via glutaraldehyde hnkage on the amine groups 

It was also found that the hybridization kinetics were found to be faster in a moving sample, as compared to a stationary sample [939]. In another report, active acoustic mixing was used to achieve a five-fold faster DNA hybridization rate. Hybridization was detected electrochemically (by AC voltammetry) based on the ferrocene redox chemistry [62], 

A DNA hybridization test that did not require labeling the target was reported. The test was based on the displacement of a fluorescently tagged indicator 

FIGURE 9.14 Optical image of the xPEG-DA hydrogel microstructures photopolymer-ized within the microchannels for sealing off microchambers (B, C), which also contained weirs to retain the beads. Scale bar, 100 pm [960]. Reprinted with permission from the American Chemical Society. 

In another report, detection of hybridization of an unlabeled target was achieved by exploiting laminar flows in microchannels. Two streams of FITC-labeled oligonucleotide probe and its unlabeled complementary target were 

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