Ultrashort electrical pulses open a new gateway into biological cells

TLDR

Short electrical pulses shorter than the membrane charging time increase the likelihood of intracellular field interactions. Intracellular electroeffects can be harnessed to deliver genes to the nucleus, manipulate calcium‑dependent cell functions, and treat tumors. Human cells exposed to 10‑ns, 300 kV/cm pulses exhibit intracellular granule membrane breach, rapid calcium influx, gene expression changes, and at higher fields submicrosecond pulses trigger apoptosis that suppresses tumor growth.

Abstract

An electrical model for biological cells predicts that for pulses with durations shorter than the charging time of the outer membrane, there is an increasing probability of electric field interactions with intracellular structures. Experimental studies in which human cells were exposed to pulsed electric fields of up to 300-kV/cm amplitude, with durations as short as 10 ns, have confirmed this hypothesis. The observed effects include the breaching of intracellular granule membranes without permanent damage to the cell membrane, abrupt rises in intracellular free calcium levels, and enhanced expression of genes. At increased electric fields, the application of submicrosecond pulses induces apoptosis (programmed cell death) in biological cells, an effect that has been shown to reduce the growth of tumors. Possible applications of the intracellular electroeffect are enhancing gene delivery to the nucleus, controlling cell functions that depend on calcium release (causing cell immobilization), and treating tumors.