We concentrate on the effects of very short (nanosecond), intense (megavolt-per-meter) pulsed electric fields on cells and tissues, combining experimental observations with molecular simulations. The focus of our recent work is the delineation and characterization of the biophysical mechanisms that govern electric field-driven, nondestructive perturbations of biological membranes.

Life is Electrical

Electric fields pervade biological systems, from the atomic interactions that determine the minimum free energy paths of ions through membrane channels to the transmission of signals through the nervous systems of multicellular animals. Every molecular link in the complex genomic, transcriptomic, proteomic web of a living cell is formed from the physical and chemical associations of atoms, which we dissect with coulombic and quantum mechanical tools.

Life is electrical at the level of the organism as well. Animals interact with their environment and with each other by sensing and in some cases generating external electric fields, and of course the consciousness which permits our contemplation of these matters is itself anchored in the complex electricity of the brain.

The Strong and Short of It

We are exposed to electric and magnetic fields throughout our lives, from natural and artificial electromagnetic radiation (the light of the sun, the cacophony of radio), and from sources like the terrestrial magnetic field, cellular telephones, hair dryers, microwave ovens, magnetic resonance imagers, and electrical power transmission lines. But, setting aside direct sunlight and the cavities of microwave ovens, the physical magnitude of these exposures is small. Despite the considerable efforts of dedicated investigators, no persuasive evidence has been presented for persistent or harmful effects from any of these fields --- assuming that one obeys common sense, avoiding sunburn and refraining from climbing into the microwave.

Of course large electric fields can and do affect living systems. Many biologists are familiar with electroporation, for example, a laboratory procedure in which cells or tissues are exposed to brief electrical pulses in order to render them permeable to normally excluded substances (like pharmacological or genetic material) or to promote cell fusion. Some of us are studying the response of cells to ultrashort, nanoseconds pulses and study nanometer scale perturbations using indirect experimental methods and molecular dynamics simulations.