Biochemistry, Biophysics, and Structural Biology Commons^™

Cellular Regulation Of Extension And Retraction Of Pseudopod-Like Blebs Produced By Nanosecond Pulsed Electric Field, Mikhail A. Rassokhin, Andrei G. Pakhomov

Bioelectrics Publications

Recently we described a new phenomenon of anodotropic pseudopod-like blebbing in U937 cells exposed to nanosecond pulsed electric field (nsPEF). In Ca²⁺ -free buffer such exposure initiates formation of pseudopod-like blebs (PLBs), protrusive cylindrical cell extensions that are distinct from apoptotic and necrotic blebs. PLBs nucleate predominantly on anode-facing cell pole and extend toward anode during nsPEF exposure. Bleb extension depends on actin polymerization and availability of actin monomers. Inhibition of intracellular Ca²⁺ , cell contractility, and RhoA produced no effect on PLB initiation. Meanwhile, inhibition of WASP by wiskostatin causes dose-dependent suppression of PLB growth. Soon after …

Dielectric Characterization Of Coastal Cartilage Chondrocytes, Michael W. Stacey, Ahmet C. Sabuncu, Ali Beskok

Bioelectrics Publications

BACKGROUND: Chondrocytes respond to biomechanical and bioelectrochemical stimuli by secreting appropriate extracellular matrix proteins that enable the tissue to withstand the large forces it experiences. Although biomechanical aspects of cartilage are well described, little is known of the bioelectrochemical responses. The focus of this study is to identify bioelectrical characteristics of human costal cartilage cells using dielectric spectroscopy.

METHODS: Dielectric spectroscopy allows non-invasive probing of biological cells. An in house computer program is developed to extract dielectric properties of human costal cartilage cells from raw cell suspension impedance data measured by a microfluidic device. The dielectric properties of chondrocytes are …

Basic Features Of A Cell Electroporation Model: Illustrative Behavior For Two Very Different Pulses, Reuben S. Son, Kyle C. Smith, Thiruvallur R. Gowrishankar, P. Thomas Vernier, James C. Weaver

Bioelectrics Publications

Science increasingly involves complex modeling. Here we describe a model for cell electroporation in which membrane properties are dynamically modified by poration. Spatial scales range from cell membrane thickness (5 nm) to a typical mammalian cell radius (10 μm), and can be used with idealized and experimental pulse waveforms. The model consists of traditional passive components and additional active components representing nonequilibrium processes. Model responses include measurable quantities: transmembrane voltage, membrane electrical conductance, and solute transport rates and amounts for the representative "long" and "short" pulses. The long pulse-1.5 kV/cm, 100 μs-evolves two pore subpopulations with a valley at ~5 …

Cancellation Of Cellular Responses To Nanoelectroporation By Reversing The Stimulus Polarity, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Betsy Gregory, Karl H. Schoenbach

Bioelectrics Publications

Nanoelectroporation of biomembranes is an effect of high-voltage, nanosecond-duration electric pulses (nsEP). It occurs both in the plasma membrane and inside the cell, and nanoporated membranes are distinguished by ion-selective and potential-sensitive permeability. Here we report a novel phenomenon of bioeffects cancellation that puts nsEP cardinally apart from the conventional electroporation and electrostimulation by milli- and microsecond pulses. We compared the effects of 60- and 300-ns monopolar, nearly rectangular nsEP on intracellular Ca²⁺mobilization and cell survival with those of bipolar 60 + 60 and 300 + 300 ns pulses. For diverse endpoints, exposure conditions, pulse numbers (1-60), and …

Introduction To Fourth Special Issue On Electroporation-Based Technologies And Treatments, Damijan Miklavčič, Lluis M. Mir, P. Thomas Vernier

Bioelectrics Publications

This fourth special electroporation-based technologies and treatments issue of the Journal of Membrane Biology contains reports on recent developments in the field of electroporation by participants in the 7th International Workshop and Postgraduate Course on electroporation based technologies and treatments (EBTT 2013) held in Ljubljana, November 17–23, 2013. The 65 participants included faculty members, invited lecturers, special guests, and young scientists, and students from 16 countries. In addition to lectures on the fundamentals, this year’s sessions included talks on microbial inactivation by pulsed electric fields, modeling of intracellular electroporation, electroporation in food processing, and electrotransfer-facilitated DNA vaccination.