A Microfluidic Chip-based Spatial Temperature Gradient Capillary Electrophoresis System For DNA Mutation Detection

Temperature gradient capillary electrophoresis (TGCE) is a new method for studying DNA mutations. At present, it is an ideal means which can detect gene segments different in length and type. In this paper, DNA mutation samples were detected by chip-based TGCE, and a simple, reliable, convenient spatial temperature gradient system was developed.The first part of the paper introduces the characteristics, separate modes and injection methods of chip-based capillary electrophoresis, the application of capillary electrophoresis in DNA mutation detection and formation methods of temperature gradient in TGCE were reviewed.In the second part, a spatial temperature gradient for DNA mutation detection of chip-based TGCE system was established. PDMS (Polydimethylsiloxane) slab with the thermal resistance varying in gradient was made, and continuous temperature gradient was formed on slab using heat exchange which was influenced by varied thermal resistance. The uniformity and stabilization of the temperature gradient were investigated. Glass microfluidic chip was put on the temperature gradient heater, and then spatial temperature gradient was formed along the channel. With temperature gradient of 10℃, the concentrations of sieving matrix, pH of buffer and field strengths were optimized by univariate method. Under the optimal conditions,209 bp DNA mutation standard samples were separated with migration time precision of 1.8% RSD (n=7), plate number of 1.0×105/m, analytical time of 8 min 15 s. K-ras gene mutations from two patients with large intestine cancer were successfully identified.In the third part, the analytical method established in this paper was summed up, and the prospect of chip-based TGCE techniques was described.