Capillary electrophoresis microchip for direct amperometric detection of DNA fragments

Detection and quantitation of nucleic acids have gained much importance in the last couple of decades, especially in the post-human genome project era. Such processes are tedious, time consuming and require expensive reagents and equipment. Therefore, in the present study, we demonstrated a simple process for the separation and analysis of small DNA fragments using capillary electrophoretic amperometric detection on an inexpensive disposable glass microchip. The device used polydimethylsiloxane engraved microchannel and Au/Ti in-channel microelectrodes for sample detection. The DNA fragments were separated under low electric field (20 V/cm) for improved detection sensitivity and to retain the biomolecules in their native conformation. With a low sample requirement (as low as 1 μL) and high reproducibility, the proposed microchip device was successful in resolution and detection of DNA fragments of various lengths.