An energy-releasing carbon nanotube transponder comprising a nanocapacitor connected to at least one carbon nanotube and method of using same are described. An adjustable amount of electric energy is stored within the nanocapacitor so that the energy-releasing carbon nanotube transponder delivers either a biologically destructive or a biologically non-destructive electrical charge to target cells in response to biological, chemical or electrical stimuli. An optional biocompatible coating onto the outer surface of the carbon nanotube transponder improves cellular targeting, cellular binding or body tolerance towards the carbon nanotube transponder. Optionally, a molecular label attached to at least one carbon nanotube allows for in vivo tracking of the carbon nanotube transponder. The targeted release of electric energy from the carbon nanotube transponder can, for example, destroy cancer cells in cancer patients, or control the flux of electric wave within a cellular tissue to treat cardiac and/or epileptic patients.