Electroporation in cancer therapy without insertion of electrodes.

Electroporation in cancer therapy in which elongated micron-sized conductors are used to enhance an externally applied electric field is investigated. Such field enhancement was previously used in carbon and boron nitride nanotube electropermeabilization. It is envisaged that the micro-conductors would be injected together with therapeutic drugs into tumorous regions, and a pulsed or alternating external field would be applied. Amplification of this external electric field at the pointed ends of the elongated micro-conductors would then give (locally) a field sufficiently large to cause electroporation. The torque of the electric field on the polarized micro-conductors will tend to align them with the field, giving the configuration of maximum field enhancement at their ends. Brownian (thermal) motion will disrupt this alignment. We give an analysis of field enhancement, torque, and thermal motion for micro-conductors of prolate spheroidal shape, and estimate the range of their size for use in human tissue.