Microfluidic Capillary Electrophoresis Combined With Automated Sample Introduction For Dna Analysis

DNA assay has been successfully applied to diagnosis, medicolegal investigation, molecular biology, and many other fields. The conventional instruments for DNA analysis are slab gel electrophoresis apparatuses, which are often limited for such defects as low sample throughput, high sample consumption and being difficult to be automated. In present work, an automated high-throughput microfluidic capillary electrophoresis system with a continuous sample introduction device based on a slotted vial array was developed.In Chapter 1, the applications of capillary electrophoresis (CE) and microfluidic CE in DNA analysis were reviewed. We focused on the sample introduction techniques of microchip-based CE systems. Moreover, the detection techniques were also described, especially fluorescence detection technique. At last, the consideration of our work design was given.In Chapter 2, an automated nanoliter sample introduction system was combined to a liquid-core waveguide (LCW)-based microfluidic capillary electrophoresis system for high-throughput analysis of DNA fragments. A 7 cm long Teflon AF-coated silica capillary serves both as the separation channel and as a LCW for light transmission. The capillary tip deposited platinum layer serves as the electrode. Continuous sample injection can be achieved during the separation of DNA fragments. The sensitivity was also improved by using SYTOX Orange as DNA dye and a diode laser as light source. Poly-(vinylpyrrolidone) (PVP) as sieving matrix possesses the virtue of being replaceable and self-coating. The sampling frequency, sample/reagent consumption and analytical efficiency were improved in the system. Performance of the system was demonstrated by the separation of DNA fragments,ΦX174-HaeⅢdigest DNA and DL2000 DNA. Baseline separation was achieved for all 11 fragments ofΦX174-HaeⅢdigest DNA at a throughput of 33/h. Theoretical plate number for 603 bp fragment was 7.3×106/m, corresponding to a plate height of 0.14μm. The detection limitation for 603 bp fragment was 0.4 ng/μL (S/N=3) with a precision of 2.2% RSD for the peak height. Automated sample changing and introduction were achieved with only 0.3 nL gross sample consumption.Remarks and some advices were proposed in the last chapter. This microfluidic CE system may have promising future not only in DNA assays but in RNA, protein, lipid and cell assays.