Rapid detection of specific genes from human genomic DNA using the microbead-quantum dot complexes in microfluidic...

In the clinic, it is important to prepare for single stranded DNA from genomic DNA to detect the target gene. In this study, we have investigated the detection of single stranded DNA (ssDNA) obtained by ultrasonication of human genomic DNA via fluorescence quenching on microfluidic chip with pillars at the channel to entrap the microbead-QD complexes (MQCs). The QDs with carboxyl group bind to microbeads with amine group by EDC/NHS coupling reaction. The thiolated probe DNA conjugates strongly with the metal ions on the surface of QDs. The MQCs were packed into a chamber on the channel blocked by pillars. ssDNA and TOTO-3 (intercalating dye) were introduced into the microchannel. After hybridization of probe DNA and target DNA, fluorescence quenching was observed at the surface of the MQDs by FRET between QD and TOTO-3. This experiment shows the possibility of rapid detection of genomic DNA from clinical samples via microbead-QD complexs on microfluidic chip.