Devices and methods for treating biological tissue using a plasma gas-discharge are disclosed herein. An electrode for igniting a gas flow to form a plasma gas-discharge, wherein the electrode is configured within the device such that upon encountering a surface of the biological tissue by the electrode, a path of current from the electrode to the surface of the biological tissue is formed, thereby igniting the gas flow and forming the plasma gas-discharge. In some embodiments, electromagnetic interactions between the treated biological tissue and the plasma gas discharge traversing the electromagnetic interaction gap shape the profile of the plasma gas discharge. According to some embodiments, the device includes an electrode for igniting gas of the gas flow, and electromagnetic interactions between the electrode and the skin determine, at least in part, the electromagnetic interactions that shape the profile of the plasma gas discharge. In some embodiments, the device further includes a housing for providing support for the electrode, wherein the electrode is disposed relative to the housing such that the electrode is substantially electrically unshielded by the housing, and the electrode is positioned to electromagnetically interact with a surface of the biological tissue to shape, at least in part, the plasma profile. According to some embodiments, the presently disclosed device includes a dual-purpose nozzle-electrode for gas delivery and for igniting the gas flow. A method of transdermal ion delivery of a plasma flux to biological tissue as a means of treating the biological tissue is also provided.
