Biomedical Engineering and Bioengineering Commons^™

Control Of The Electroporation Efficiency Of Nanosecond Pulses By Swinging The Electric Field Vector Direction, Vitalii Kim, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Ruben M. L. Colunga Biancatelli, Andrei G. Pakhomov

Bioelectrics Publications

Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as “bipolar cancellation,” enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing …

Connexin Hemichannel Activation By S-Nitrosoglutathione Synergizes Strongly With Photodynamic Therapy Potentiating Anti-Tumor Bystander Killing, Chiara Nardin, Chiara Peres, Sabrina Putti, Tiziana Orsini, Claudia Colussi, Flavia Mazzarda, Marcello Raspa, Ferdinando Scavizzi, Anna Maria Salvatore, Francesco Chiani, Abraham Tettey-Matey, Yuanyuan Kuang, Guang Yang, Mauricio A. Retamal, Fabio Mammano

Bioelectrics Publications

In this study, we used B16-F10 cells grown in the dorsal skinfold chamber (DSC) preparation that allowed us to gain optical access to the processes triggered by photodynamic therapy (PDT). Partial irradiation of a photosensitized melanoma triggered cell death in non-irradiated tumor cells. Multiphoton intravital microscopy with genetically encoded fluorescence indicators revealed that bystander cell death was mediated by paracrine signaling due to adenosine triphosphate (ATP) release from connexin (Cx) hemichannels (HCs). Intercellular calcium (Ca²⁺) waves propagated from irradiated to bystander cells promoting intracellular Ca²⁺ transfer from the endoplasmic reticulum (ER) to mitochondria and rapid activation of …

Biomanufacturing Organized Collagen-Based Microfibers As A Tissue Engineered Device (Tend) For Tendon Regeneration, Yas Maghdouri-White, Nardos Sori, Stella Petrova, Hilary Wriggers, Nathan Kemper, Amrita Dasgupta, Kelly Coughenour, Seth Polk, Nick Thayer, Mario Rodriguez, Bill Simon, Anna Bulysheva, Kevin Bonner,, Steven Arnoczky, Samuel Adams, Michael Francis

Bioelectrics Publications

Approximately 800,000 surgical repairs are performed annually in the U.S. for debilitating injuries to ligaments and tendons of the foot, ankle, knee, wrist, elbow and shoulder, presenting a significant healthcare burden. To overcome current treatment shortcomings and advance the treatment of tendon and ligament injuries, we have developed a novel electrospun Tissue ENgineered Device (TEND), comprised of type I collagen and poly(D,L-lactide) (PDLLA) solubilized in a benign solvent, dimethyl sulfoxide (DMSO). TEND fiber alignment, diameter and porosity were engineered to enhance cell infiltration leading to promote tissue integration and functional remodeling while providing biomechanical stability. TEND rapidly adsorbs …

Targeting Ovarian Cancer And Endothelium With An Allosteric Ptp4a3 Phosphatase Inhibitor, Kelley E. Mcqueeney, Joseph M. Salamoun, James C. Burnett, Nektarios Barabutis, Paula Pekic, Sophie L. Lewandowski, Danielle C. Llaneza, Robert Cornelison, Yunpeng Bai, Zhong-Yin Zhang, John D. Catravas

Bioelectrics Publications

Overexpression of protein tyrosine phosphatase PTP4A oncoproteins is common in many human cancers and is associated with poor patient prognosis and survival. We observed elevated levels of PTP4A3 phosphatase in 79% of human ovarian tumor samples, with significant overexpression in tumor endothelium and pericytes. Furthermore, PTP4A phosphatases appear to regulate several key malignant processes, such as invasion, migration, and angiogenesis, suggesting a pivotal regulatory role in cancer and endothelial signaling pathways. While phosphatases are attractive therapeutic targets, they have been poorly investigated because of a lack of potent and selective chemical probes. In this study, we disclose that a potent, …

Wild-Type P53 Enhances Endothelial Barrier Function By Mediating Rac1 Signalling And Rhoa Inhibition, Nektarios Barabutis, Christiana Dimitropoulou, Betsy Gregory, John D. Catravas

Bioelectrics Publications

Inflammation is the major cause of endothelial barrier hyper-permeability, associated with acute lung injury and acute respiratory distress syndrome. This study reports that p53 "orchestrates" the defence of vascular endothelium against LPS, by mediating the opposing actions of Rac1 and RhoA in pulmonary tissues. Human lung microvascular endothelial cells treated with HSP90 inhibitors activated both Rac1- and P21-activated kinase, which is an essential element of vascular barrier function. 17AAG increased the phosphorylation of both LIMK and cofilin, in contrast to LPS which counteracted those effects. Mouse lung microvascular endothelial cells exposed to LPS exhibited decreased expression of phospho-cofilin. 17AAG treatment …

Alteration Of Metabolite Profiling By Cold Atmospheric Plasma Treatment In Human Myeloma Cells, Dehui Xu, Yujing Xu, Ning Ning, Qingjie Cui, Zhijie Liu, Xiaohua Wang, Dingxin Liu, Hailan Chen, Michael G. Kong

Bioelectrics Publications

BACKGROUND: Despite new progress of chemotherapy in multiple myeloma (MM) clinical treatment, MM is still a refractory disease and new technology is needed to improve the outcomes and prolong the survival. Cold atmospheric plasma is a rapidly developed technology in recent years, which has been widely applied in biomedicine. Although plasma could efficiently inactivate various tumor cells, the effects of plasma on tumor cell metabolism have not been studied yet.

METHODS: In this study, we investigated the metabolite profiling of He plasma treatment on myeloma tumor cells by gas-chromatography time-of-flight (GC-TOF) mass-spectrometry. Meanwhile, by bioinformatic analysis such as GO and …

Quantitative Limits On Small Molecule Transport Via The Electropermeome - Measuring And Modeling Single Nanosecond Perturbations, Esin B. Sözer, Zachary A. Levine, P. Thomas Vernier

Bioelectrics Publications

The detailed molecular mechanisms underlying the permeabilization of cell membranes by pulsed electric fields (electroporation) remain obscure despite decades of investigative effort. To advance beyond descriptive schematics to the development of robust, predictive models, empirical parameters in existing models must be replaced with physics- and biology-based terms anchored in experimental observations. We report here absolute values for the uptake of YO-PRO-1, a small-molecule fluorescent indicator of membrane integrity, into cells after a single electric pulse lasting only 6 ns. We correlate these measured values, based on fluorescence microphotometry of hundreds of individual cells, with a diffusion-based geometric analysis of pore-mediated …

A 'Tissue Model' To Study The Barrier Effects Of Living Tissues On The Reactive Species Generated By Surface Air Discharge, Tongtong He, Dingxin Liu, Han Xu, Zhichao Liu, Dehui Xu, Dong Li, Qiosong Li, Mingzhe Rong, Michael G. Kong

Bioelectrics Publications

Gelatin gels are used as surrogates of human tissues to study their barrier effects on incoming reactive oxygen and nitrogen species (RONS) generated by surface air discharge. The penetration depth of nitrite into gelatin gel is measured in real time during plasma treatment, and the permeabilities of nitrite, nitrate, O₃ and H₂O₂ through gelatin gel films are quantified by measuring their concentrations in the water underneath such films after plasma treatment. It is found that the penetration speed of nitrite increases linearly with the mass fraction of water in the gelatin gels, and the permeabilities of …

Membrane Channel Gene Expression In Human Costal And Articular Chondrocytes, A. Asmar, R. Barrett-Jolley, A. Werner, R. Kelly Jr., M. Stacey

Bioelectrics Publications

Chondrocytes are the uniquely resident cells found in all types of cartilage and key to their function is the ability to respond to mechanical loads with changes of metabolic activity. This mechanotransduction property is, in part, mediated through the activity of a range of expressed transmembrane channels; ion channels, gap junction proteins, and porins. Appropriate expression of ion channels has been shown essential for production of extracellular matrix and differential expression of transmembrane channels is correlated to musculoskeletal diseases such as osteoarthritis and Albers-Sch€onberg. In this study we analyzed the consistency of gene expression between channelomes of chondrocytes from human …

Temporal Modulation Of Plasma Species In Atmospheric Dielectric Barrier Discharges, Aijun Yang, Xiaohua Wang, Dingxin Liu, Mingzhe Rong, Michael G. Kong

Bioelectrics Publications

The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature and the moment of maximum species densities is almost consistent with peak discharge current density. In this paper, a one-dimensional fluid model is used to investigate the temporal structure of plasma species in an atmospheric He-N₂ dielectric barrier discharge (DBD). It is demonstrated that there exist microsecond delays of the moments of the maximum electron and ion densities from the peak of discharge current density. These time delays are caused by a competition between the electron impact and Penning ionizations, modulated by the N_{2 …}

The Use Of An In Vitro 3d Melanoma Model To Predict In Vivo Plasmid Transfection Using Electroporation, Benadette Marrero, Richard Heller

Bioelectrics Publications

A large-scale in vitro 3D tumor model was generated to evaluate gene delivery procedures in vivo. This 3D tumor model consists of a "tissue-like" spheroid that provides a micro-environment supportive of melanoma proliferation, allowing cells to behave similarly to cells in vivo. This functional spheroid measures approximately 1 cm in diameter and can be used to effectively evaluate plasmid transfection when testing various electroporation (EP) electrode applicators. In this study, we identified EP conditions that efficiently transfect green fluorescent protein (GFP) and interleukin 15 (IL-15) plasmids into tumor cells residing in the 3D construct. We found that plasmids …

Nanoelectropulse-Driven Membrane Perturbation And Small Molecule Permeabilization, P. Thomas Vernier, Yinghua Sun, Martin A. Gundersen

Bioelectrics Publications

Background
Nanosecond, megavolt-per-meter pulsed electric fields scramble membrane phospholipids, release intracellular calcium, and induce apoptosis. Flow cytometric and fluorescence microscopy evidence has associated phospholipid rearrangement directly with nanoelectropulse exposure and supports the hypothesis that the potential that develops across the lipid bilayer during an electric pulse drives phosphatidylserine (PS) externalization.

Results
In this work we extend observations of cells exposed to electric pulses with 30 ns and 7 ns durations to still narrower pulse widths, and we find that even 3 ns pulses are sufficient to produce responses similar to those reported previously. We show here that in contrast to …

Stimulation Of Capacitative Calcium Entry In Hl-60 Cells By Nanosecond Pulsed Electric Fields, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Stephen J. Beebe

Bioelectrics Publications

Nanosecond pulsed electric fields (nsPEFs) are hypothesized to affect intracellular structures in living cells providing a new means to modulate cell signal transduction mechanisms. The effects of nsPEFs on the release of internal calcium and activation of calcium influx in HL-60 cells were investigated by using real time fluorescent microscopy with Fluo-3 and fluorometry with Fura-2. nsPEFs induced an increase in intracellular calcium levels that was seen in all cells. With pulses of 60 ns duration and electric fields between 4 and 15 kV/cm, intracellular calcium increased 200-700 nM, respectively, above basal levels (similar to100 nM), while the uptake of …