Electrodes for tissue stimulation and sensing can comprise a support with nanostructures disposed on the support. Pairs of the electrodes can be placed in close proximity to one another. When electrical energy is supplied to the electrodes, an electrical field (and possibly an electrical current) can be established between the nanostructures on the electrodes. The nanostructures may have cells disposed thereon, for example myocardial cells, myocardial progenitor cells, neural cells and/or stem cells. In addition, the electrodes can be arranged in arrays.