Low-voltage electroporation with fluidic microelectrodes

Electroporation is a widely used method for increasing the permeability of the cellular membrane. Impermeant exogenous substances (e.g., DNA, proteins, peptides, dyes) can thus be introduced into the cells. In this study, we have developed an electroporation system for mammalian cells on a microfluidic platform. It is a simple microsystem able to realize permeation processes without using metal electrodes to control the electric field applied to each cell and the pulse duration. In our design, a hydrodynamic focusing of fluids with different conductivities allows for performing electroporation processes in a defined area of the microfluidic channel. Thus, a continuous direct current (DC) is sufficient for supplying the system. No pulse generator or other complex electronic equipment is required. The time for which the cells are exposed to the high electric field is determined by the ratio of the fluid velocities. Electropermeation of yeast cells was observed after applying even comparatively low voltages (<2 V). Under different electrical conditions, i.e., by varying the ratio of the fluid velocities, electroporation of mammalian cells U-937 was also obtained. Our system proved to electropermeate cells while maintaining their viability. Given its simple design, this technique may be especially suited for on-chip integration. By combining it with other manipulation units, a new system for biotechnological application might be developed. ? 2012 Elsevier B.V. All rights reserved.EI707-7109