High-efficiency Low-voltage Electroporation Using Field Constriction at Micro Orifice

We developed a novel electroporation method based on field constriction, where a biological cell is immobilized on a micro-orifice opened on an electrically insulating plate, across which a pulse voltage is applied. Due to field constriction, most voltage drop occurs around the orifice, so that the voltage applied to the electrodes is impressed directly to the cell membrane on the orifice. The reversible membrane breakdown, i.e. poration, occurs exclusively at the orifice, at a voltage as low as 1-2 V. However, when the breakdown takes place, electrical current starts to flow through the opened pore, and induces breakdown at other location of cell membrane that could lead to cell destruction. In order to avoid such breakdown propagation, we developed the method of using RF-modulated pulse voltage instead of the conventional step pulse voltage. With the method, electroporation yield of 90% is achieved for the cells on a 10 times 10 orifice array