Fabrication of electro-microfluidic channel for single cell electroporation.

The point of this paper is to demonstrate the use of a quick and cheap fabrication method to realize a laser-ablated microfluidic channel for single cell electroporation. Traditional lithography of microchannel with electrode in MEMS applications has always been complicated. Here, we introduce a new methodology of fabricating microchannel with electrical functionalities achieved through a fast and cheap process. In the present methodology, the microchannel pattern is cut out of polyimide, bonded to two ITO-coated substrates using Teflon as an adhesion layer. ITO as conductive material enables electric field in the channel and its optical transparency allows microscopy techniques to be utilized in characterizing the behavior of the microfluidic chip. The performance of the chip was tested on irreversible single-cell scale electroporation which requires relatively high voltages. CHO cells, as mammalian cells, were passed through the microchannel to experience electric field. Cells were loaded with a fluorogenic dye, Calcein AM, and the electroporation of each was individually recorded in real-time via fluorescent microscopy. The results show promising performance of the electric microchannel in electroporation. By customizing of ITO electrodes and the design of microchannel pattern, utilization and integration of the proposed electrical microchannel in variety of other MEMS-based devices are achievable.