Killing tumor cells with sniper precision is a difficult task, as most contemporary clinical therapies tend to injure healthy tissue as well. AngioDynamics, a company out of Queensbury, New York, has developed a device, called the NanoKnife, that implements technology called irreversible electroporation to electrically target and kill specific tumor cells. This radiofrequency interstitial tissue ablation system one day could be used either during open tumor resection procedures, laparoscopically, or even percutaneously. The company is currently undergoing trials and developing targeting criteria and defining what settings to use on various types of tumors.
IEEE Spectrum Online explains the device:
The NanoKnife delivers quick bursts of energy through a set of electrodes inserted into and around the tumor. The pulses can last up to 100 microseconds and create an electrical field of up to 3000 volts per centimeter. A cell within range of the electric field will form pores in its fatty membrane, allowing ions to rush through. When electroporation is performed with a lower voltage than the NanoKnife delivers, and with single pulses instead of a train of pulses, the pores will eventually close as the electric potential of the cell stabilizes. Microbiologists have used this kind of reversible electroporation, among many other things, to transport genetic material into stem cells. When exposed to higher voltages and longer pulse duration, however, the pores in the cell membrane remain open and cause the cell to initiate a programmed suicide, known as apoptosis.
The electroporator works with both unipolar and up to six bipolar electrodes. Proper placement largely determines how successful the ablation will be, especially with the bipolar electrodes, which must be spaced correctly in order to produce a spherical electrical field. Complicating things further is the fact that the conductivity of tissue varies from organ to organ.