Ultrashort electrical pulses open a new gateway into biological cells

Ultrashort electric pulse induced changes in cellular dielectric properties

“…the pores reseal) as long as the pore radius remains below a certain critical radius, r crit [25,26]. While 10 ns pulses are generally too short to induce electroporation [4], applying multiple pulses charges the cell membrane more, increasing the likelihood of exceeding r crit [26]. Using a lower conductivity buffer also reduces the electroporation threshold for nsPEFs [27].…”

“…Many applications require temporarily opening the cell membrane to normally impermeant molecules, such as electrochemotherapy and gene therapy [3]. Applying pulses with higher field strength (50-300 kV/cm) and shorter duration (10-300 ns) do not fully charge the cell membrane and instead interact primarily with the membranes of intracellular organelles [4]. These nanosecond duration PEFs (nsPEFs) cause intracellular calcium release [5,6] and apoptosis-induction in cell suspensions and in vivo tumors [5,7,8].…”

Nanosecond electric pulses penetrate the nucleus and enhance speckle formation

“…Compared to traditional electroporation, nsPEFs preferentially charge the membranes of subcellular organelles, thereby inducing distinct effects on cellular structure and function that are predominantly intracellular in nature [1,2,5,8]. The resulting delayed plasma membrane permeabilization was likely secondary, arising due to subcellular effects [2] rather than direct electroporation [18,19].…”

“…The resulting delayed plasma membrane permeabilization was likely secondary, arising due to subcellular effects [2] rather than direct electroporation [18,19]. In previous confocal microscopic real time studies, we compared the nuclear and plasma membrane effects of 10 and 60 ns pulses of approximately the same energy [5].…”

“…When cells are exposed to intense (50-300 kV/cm) pulsed electric fields (PEFs) with rise times faster than the time it takes for charges on the plasma membrane to redistribute, the electric field can penetrate into the interior of the cell and organelles. If these fields exceed the breakdown threshold of these membranes, nanopores will form in the organelle membranes [1,2]. To better understand the mechanism involved, mathematical models for the cellular electropermeabilization due to nsPEFs have been developed [3,4].…”