Development of a gel-to-gel electro-kinetic pinched injection method for an integrated micro-fluidic based DNA analyser

An integrated gel supported micro-fluidic system is reported, in which PCR products can be efficiently injected into a capillary electrophoresis device. The gel supported system is designed to provide greater stability to reagents during long periods of dormancy, enabling the mass production of one use chips encapsulating all required reagents at the time of manufacturing. This simultaneously diminishes the risk of sample contamination, and reduces the amount of external hardware required for auxiliary flow control, thus increasing the potential for portability. After PCR amplification was performed in a polysaccharide gel matrix, the PCR product was injected into the separation gel polymer matrix by executing a capillary-based electro-kinetic pinched injection across a gel-to-gel interface. The gel-to-gel system delivered a precise and accurate plug into the separation polymer, which offered more stable electro-kinetic control of the sample compared to solution based methodology even when bubbles were present in the system. Suitable voltage control was proven to provide a repeatable electro-kinetic injection of PCR product sufficient for an on-chip separation of multiple loci by capillary electrophoresis.