Electrical charges destroy cancer cells

July 10, 2007

Heating and cryoablation of cancer tumors through ultrasound or liquid nitrogen might have a competitor: an electrical transformation of the cell being studied at Virginia Tech and the University of California, Berkeley. The new, minimally invasive method, which has shown promising results in preclinical trials, is being readied for clinical testing on patients with prostate cancer.

Heating and cryoablation of cancer tumors through ultrasound or liquid nitrogen might have a competitor: an electrical transformation of the cell being studied at Virginia Tech and the University of California, Berkeley. The new, minimally invasive method, which has shown promising results in preclinical trials, is being readied for clinical testing on patients with prostate cancer.

The underlying process, called irreversible electroporation (IRE), changes the permeability of cells from closed to open using a series of short, intense electric pulses from electrodes placed in or around the body. This change in permeability causes the cells to die, according to Rafael V. Davalos, coinventor of the technique and director of the bioelectromechanical systems laboratory at the School of Biomedical Engineering and Sciences at Virginia Tech-Wake Forest University.

"It creates permanent openings in the pores in the cells of the undesirable tissue," Davalos said. "The openings eventually lead to the death of the cells without the use of potentially harmful chemotherapeutic drugs."

Electroporation has been known for decades to increase the permeability of a cell. Davalos and Boris Rubinsky, a bioengineering professor at the University of California, Berkeley, took it one step further and applied the concept to target cancer cells.

In preclinical testing, the technique was used successfully to ablate tissue in the livers of male Sprague-Dawley rats. The targeted cells were destroyed and the vessel architecture preserved, Davalos said, by adjusting the electrical current to keep surrounding tissue and nearby blood vessels unaffected.

"IRE is easy to apply, is not affected by local blood flow, and can be monitored and controlled using electrical impedance tomography," he said.