A microelectrode or an array of microelectrodes for communicating with one or more adjacent electrically excitable cells. The microelectrode array comprises two or more microelectrodes. Each microelectrode comprises a body with a perimeter； an electrode wire that is electronically connected to the body and that is electronically connectible to an electronic system； and a ridge that extends away from the perimeter of the body for increasing a sealing-resistance value between the electrode and the one or more adjacent electrically excitable cells.
