Electroporation microchips for continuous gene transfection

Electroporation is a technique with which DNA molecules can be delivered in to cells in a chamber using high electric field pulses. Compared to the com mercial equipment, the fabricated flow-type electroporation microchip overc omes the limit in the amount of target cells and the potential risk of usin g high voltage, which are the two drawbacks in current electroporation tech nology. The flowing mechanism eliminates the temperature-rising effect foun d in a commercial sterile plastic cuvette during electroporation and thus c an improve the survival rate of cells after electroporation. The electroporation microchip, consisting of a micro-channel with gold thin film electrodes on both sides, was fabricated on PMMA material using evapo ration, photolithography, lift-off and fusion-bonding methods. The suspensi on fluid of Huh-7 cell lines mixed with reporter genes flowed through the c hannel under a series of electrical square pulses. Trypan blue staining was used to assess the viability of the cells treated with pulses. The cells w ere evaluated under a microscope. The dimensions of the channel were 5 mm wide, 0.2 mm high and 25 mm long. C ell experiments demonstrated that our microchip could transfect the flowing cells with the expression of reporter genes with lower dissipated heat. Th e survival rate increased with a lower pulse frequency and a higher flow sp eed. Our newly designed novel microchip for electroporation of continuous c ell flow will have great potential for future gene delivery in hematologic malignancy. (C) 2001 Elsevier Science B.V. All rights reserved.