Micro electrode array for recording electrical membrane ionic currents

Studying the ionic current activity in cells is useful in understanding the cell behavior, e.g. during wound healing and formation of embryos. Measuring the intracellular ion activities across the cell membrane is important in understanding cellular functions related to ion activities. A novel design using micro electrode arrays (MEA) for measuring ionic currents from cell membrane is presented here. The novel design of the electrodes enables the separation of the cells and the metal electrodes. This avoids cell contamination as there are no toxic chemicals produced at the cell surface by the electrode-cell-interaction. An electrically conducting medium (agar-agar) connects the cell to the electrode. The electrode has a layer of Ag/AgCl which is electrochemically deposited on patterned gold. The cells are suspended on top of a bio-compatible porous membrane in a medium. Soft-lithography technique is used to form the micro-fluidic channels made of Polydimethylsiloxane (PDMS) in which the electrolyte flows that connects cell and electrode. The cells are stimulated by a DC current generated using an agar bridge setup. Detailed fabrication of the MEA will be presented in this paper.