Microchip Capillary Electrophoresis Device for Amperometric Detection of DNA with Redox Intercalation

Microfabricated biochips are very efficient platforms for analysis of biologically important molecules such as DNA, RNA, enzymes, antibodies etc. These devices requires sample in micro/nano volume and produces faster and better results. For these reasons, we fabricated a simple, disposable microfluidic device for amperometric detection of DNA intercalated with methylene blue redox dye. The devices were fabricated using conventional photolithographic method. The microchannels were laid in PDMS using negative molding. The microchannel was 2 cm in length while the height and thickness were 250 μm and 200 μm respectively. The electrodes used for electrophoretic separation and amperometric detection were made of gold and were deposited by thermal evaporation on glass substrate. For the detection of DNA, fish sperm DNA was intercalated with methylene blue as an analyte. The cyclic voltammograms of free methylene blue and those of different concentrations of DNA intercalated with same amount of methylene blue was obtained in this study. The intercalated DNA was then injected in the sample reservoir of fabricated device and subjected to a separation electric field. The i-t curve was monitored for this process. The electropherograms thus obtained suggested a possibility of rapid detection of DNA with high sensitivity and reproducibility.