A novel approach to DNA transfection of Escherichia coli DH5(alpha) cells using a microfluidic chip

Microfluidic devices are recently being used for various microbiological purposes. The process of perforating living cells and transfecting them with different biological moieties, a process commonly known as electroporation was performed on chip by flowing E. coli DH5α cells through a single channel and applying high voltage pulses across a small segment. Cells were treated with fluo-4 dye before exposure to these pulses in presence of Ca2+. Detection using a PMT was used to monitor the fluorescence due to the formation of Ca2+ and fluo-4 complex within the cells after electroporation. Similar experiments were performed using ampicillin resistant pbskll and GFP(uv) plasmid instead of Ca 2+ and no dye. The cells were pumped out of the chip, diluted with LB broth and cultivated on ampicillin resistant agar plates in order to determine transfection efficiencies. Due to poor transfection efficiencies from insufficient electric field, leakage and clogging effects in the chip, a new device was designed, fabricated and tested. Transfection efficiencies obtained from this device differ from commercially available instruments by 1 to 2 orders of magnitude.