Local electrical stimulation of cultured embryonic cardiomyocytes with sub-micrometer nail structures

A novel 16k micro-nail CMOS-chip for in-vitro single-cell recording, stimulation and impedance measurements

In neurophysiological and pharmaceutical research, parallel and individual access to a dense population of in-vitro cultured neurons is a key feature for analyzing networks of neurons. This paper presents a 0.18µm CMOS chip containing a dense array of micro-nail electrodes, a 128×128 sensor/actuator matrix with in-situ differential amplification circuits, pico-Ampere current stimulation, and impedance measurement circuits. Measurements on packaged chips show successful impedance measurements matching the simulation model and electrical recordings of in-vitro cultured cardiomyocytes, correlated with recorded changes in intra-cellular calcium concentrations. This system is a first step towards a high-throughput neuron/chip interface.

Local electrical stimulation of single adherent cells using three-dimensional electrode arrays with small interelectrode distances

In this paper, we describe the localized and selective electrical stimulation of single cells using a three-dimensional electrode array. The chip consisted of 84 nail-like electrodes with a stimulation surface of 0.8 microm(2) and interelectrode distances as small as 3 microm. N2A cells were used to compare bipolar stimulation between one electrode in- and one outside the cell on the one hand, and two electrodes in the same cell on the other hand. Selective and localized stimulation of primary embryonic cardiomyocytes showed the possibility to use this chip with excitable cells. The response of the cells to applied electrical fields was monitored using calcium imaging whereas assessment of electroporation was determined following influx of propidium iodide. Arrays of these three-dimensional electrodes could eventually be used as a tool to selectively electroporate the membrane of single cells for genetic manipulation or to obtain electrical access to the inner compartment of the cell.