For DNA Electrochemical Detection on Microfluidic Gene Chip
On the microfluidic gene chip, due to high difficulty in temperature changes frequently and products detecting equipment miniaturize, the conventional methods of DNA detection can’t meet the requirements. In this paper, a newly electrochemical method, cyclic voltammetry, basing on a set of special electrodes and the Loop-mediated isothermal amplification (LAMP), was introduced. The DNA amplification products of LAMP could be combined with the positive dye (Methylene blue), which leading to a reduction in the oxidation peak current (ipA) and reduction peak current (ipC) of the cyclic voltammetry. The changes of ipA/ipC were real-time measured by the special electrodes, so the copies of DNA were quantitative detected. The results show that it could be completed in 30～60 minutes with the lowest DNA to 10 CFU.mL-1, with high accuracy (96.5%), high sensitivity (96.0%), high specificity (97.0%) compare to the PCR, and good anti-interference ability against Vitamin C (up to 32mg.L
-1) and Aspirin (up to 64mg.L-1) within the sample. Therefore, it was a rapid, sensitive and stable method of DNA detection, has great potential in applying on the microfluidic gene chips.
Today, the polymerase chain reaction (PCR) had become the common method of DNA detection. Basing on basis PCR, the scientists had developed a series of technologies, such as multiplex PCR , microfluidic chip PCR , and isothermal PCR . The microfluidic chip PCR requires simplified workflows. The simple construction lends itself to low-cost and ease of manufacturing, yet several features reduce the complexity of the standard microarray workflow . The microfluidic PCR systems have set milestones for small volume (100 nL～5μL), amplificationspeed (100～400 s), and on-chip integration of upstream and downstream sample handling .