A novel micro-fluidic biosensor for the rapid and sequence-specific detection of DNA with electrophoretic driving mode and laser-induced fluorescence detector

A novel DNA biosensor, which combines the merits of micro-fluidic chips, the electrophoretic driving mode, paramagnetic beads amplification, and laser-induced fluorescence detection was developed for the rapid and sequence-specific detection of DNA in this study. The proposed DNA biosensor has much higher discrimination ability for the detection of single-base mismatch and much stronger resistibility to the complex matrixes of real samples in comparison with previous biosensors. These features, as well as its ease of fabrication (the fabrication of the sensor takes only 10 min except the fabrication of micro-fluidic chip), operation convenience, stability, better re-usability (micro-fluidic chip can be reused without any extra treatment) and short analysis time (one determination only takes 15 min), make it a promising alternative to rapid detection of DNA in clinical diagnosis. With the help of the biosensor, we successfully determined DNA, which related to oral cancer, in a saliva sample without any pre-separation or dilution with a detection limit of 4.2 × 10^?11 M and a relative standard deviation (n = 5) <5 %. The success in the present biosensor served as a significant step toward the practical application of the biosensor in clinical diagnosis.