Biomedical Engineering and Bioengineering Commons^™

Design And Characterization Of A Pulsed Electric Field Chamber For Microalgae Lysis, Connor Strutin

Electrical Engineering

Microalgae are a promising renewable source of biofuel due to their high lipid content and rapid growth rates; however, algae cells must be electroporated (lysed) to release these lipids. The system developed in this project applies short (40 μs–10 ms), high-intensity (up to 33 kV/cm) pulsed electric fields (PEF) across cell membranes to enable electroporation.

Our lab-scale PEF chamber generates uniform, high-intensity electric fields using parallel-plate electrodes with sub-millimeter spacing. The system is designed to efficiently lyse microalgae cells for lipid extraction and biofuel production.

Peculiarities Of Phosphatidylserine Externalization By Nano- And Microsecond Electric Pulses, Mantas Silkunas, Alayna Enos, Iurii Semenov, Giedre Silkuniene, Eleni Zivla, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

Phosphatidylserine (PS) externalization is a hallmark of apoptosis but can also be triggered within seconds by pulsed electric fields (PEFs). Whether PS reaches the outer leaflet by lateral migration through electropores or indirectly through Ca²⁺-dependent signaling and scramblase activation remains debated. We used total internal reflection fluorescence (TIRF) microscopy with Annexin V-Alexa Fluor 568 and/or bovine lactadherin-FITC to resolve PS externalization in HEK293 cells placed on an indium tin oxide (ITO) transparent electrode. PEF exposures produced discrete PS-positive puncta ("freckles") within ~ 10 s after a 20-µs pulse (1.2-2.5 kV/cm) or with a ~ 1-min delay after a …

Nanosecond Pulsed Electric Fields For Extracellular Vesicle Engineering: From Electro-Exocytosis To Cargo Modulation, Art Neal, Teresa Graham, Mohamadmahdi Samandari, Arash Ghorbannia, Anca Dobrian, Stephen J. Beebe, Ruben M. L. Colunga-Biancatelli

Bioelectrics Publications

Extracellular vesicles (EVs), including small extracellular vesicles (sEVs) and medium/large extracellular vesicles (MVs), have emerged as promising therapeutic vectors and diagnostic biomarkers across various branches of biomedicine. However, the clinical translation of EV-based technologies remains constrained by persistent challenges in manufacturing: insufficient yield from primary cell sources, limited control over cargo composition, and the absence of scalable, standardized production platforms. Nanosecond pulsed electric fields (nsPEF) represent an emerging biophysical approach that can address several of these limitations. Unlike conventional electroporation, which targets the plasma membrane using microsecond-to-millisecond pulses, nsPEF delivers ultrashort (1–300 ns), high-amplitude (10–300 kV/cm) pulses that penetrate intracellularly …

Electroporation Protocol Development For Cal Poly Cell Therapy Laboratory Courses, Gabrielle Melamed

Biomedical Engineering

Cancer is a heterogeneous disease caused by unchecked cell proliferation. The disease contributed to 9.7 million deaths worldwide in 2022, with hematological malignancies (leukemias, lymphomas, and myelomas) accounting for over 1.4 million deaths in the United States from 1999 to 2020. This thesis focuses on the treatment of these cancers, with an emphasis on non-Hodgkin lymphomas (NHLs). R-CHOP (Rituximab-Cyclophosphamide, Doxorubicin hydrochloride, Oncovin/Vincristine, and Prednisone) is the standard of care first-line treatment for diffuse large B-cell lymphoma (DLBCL), the most common subtype of NHL, and encompasses a mixture of chemotherapy, immunotherapy, and corticosteroids. The R-CHOP regimen cures 50% to 70% patients, …

Ex Vivo Multiplex Knockdown Of Angptl3 And Cypor In Hepatocytes As A Novel Cell Therapy For Familial Hypercholesterolemia, Callie D. Clark

All Dissertations

Inherited metabolic diseases (IMDs) affect approximately 1 in 800 individuals. The only curative treatment for IMDs is liver transplantation. However, transplantation carries significant risks, including organ rejection and a lifelong need for immunosuppression. Therefore, gene editing has emerged as a promising alternative to liver transplantation for treating IMDs.

Familial hypercholesterolemia (FH) is and IMD characterized by elevated LDL-C levels resulting in premature cardiovascular disease. CRISPR-Cas9-mediated gene editing to disrupt the gene encoding angiopoietin-like 3 (ANGPTL3) in the liver represents a novel therapeutic approach for FH. Nonviral delivery performed ex vivo is safer than systemic delivery because gene editing is in …

Development Of A Xenograft For Annular Repair Using Pulsed Electric Field Exposures For Enhanced Decellularization, Prince Mensah Kwaku Atsu

Theses and Dissertations

Severe back injuries and chronic pain necessitate surgical replacement of damaged intervertebral disc (IVD) cartilage in advanced disease stages. Bovine IVD tissue has been exposed to an upper threshold pulsed electric field (PEF) dose, causing cell death without thermal damage to the tissue. Subsequent PEF exposures at lower magnitudes have accelerated the removal of immunogenic biomolecules though electrokinetic extraction using optimized aqueous solutions. This approach yields a natural scaffold, ready for biocompatibility and mechanical strength assessment. The effects of microsecond pulsed electric fields (µsPEF) on primary bovine AF fibroblast-like cells have been characterized in vitro. PEFs of 10 and 100 …

Dihydroethidium-Derived Fluorescence In Electrically Stressed Cells Indicates Intracellular Microenvironment Modifications Independent Of Ros, Esin B. Sözer, Iurii Semenov, P. Thomas Vernier

Bioelectrics Publications

Intracellular reactive oxygen species (ROS) generation is widely suggested as a trigger for biological consequences of electric field exposures, such as those in electroporation applications. ROS are linked with membrane barrier function degradation, genetic damage, and complex events like immunological cell death. Dihydroethidium (DHE) is commonly used to monitor ROS in cells. DHE is linked to intracellular ROS by a primary oxidation product, Ethidium (Eth⁺), that shows increased fluorescence upon binding to polynucleotides. We observed changes in DHE-derived fluorescence in Chinese hamster ovary (CHO) cells post 300-ns electric pulse exposures, comparing them to tert-butyl-hydroperoxide (t-BHP) induced oxidative stress. …

Dynamics Of Cell Membrane Lesions And Adaptive Conductance Under The Electrical Stress, Mantas Silkunas, Olga N. Pakhomova, Giedre Silkuniene, Andrei G. Pakhomov

Bioelectrics Publications

Exceeding physiological limits of the cell membrane potential compromises structural integrity, enabling the passage of normally impermeant solutes and disrupting cell function. Electropermeabilization has been studied extensively at the cellular scale, but not at the individual membrane lesion level. We employed fast total internal reflection fluorescence (TIRF) imaging of Ca(2+) entry transients to discern individual lesions in a hyperpolarized cell membrane and characterize their focality, thresholds, electrical conductance, and the lifecycle. A diffuse and momentary membrane permeabilization without a distinct pore formation was observed already at a -100 mV threshold. Polarizing down to -200 mV created focal pores with a …

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Exploration Of Corona Charge As A Novel In Vitro Human T Cell Dna Transfection Method, Molly A. Skinner

USF Tampa Graduate Theses and Dissertations

With gene-based immunotherapies on the rise to treat a multitude of diseases, the ability to genetically modify cells in a rapid and efficient fashion is necessary to keep up with demand. Gene electrotransfer (gene transfer by electroporation) is an appealing transfection method due to its low cost, high efficiency compared to other physical forms of gene delivery, and low toxicity compared to liposomal or viral vectors.

Traditional gene delivery via electroporation is done within a cuvette where the cell suspension is placed between two plate electrodes. This method requires cells to be moved from the treatment cuvette to a growth …

Characterization And Implementation Of An All-In-One Heating, Impedance, And Pulsing Device For Molecular Delivery Applications, Alex Otten

USF Tampa Graduate Theses and Dissertations

Cancer impacts millions of Americans every year, with an estimated 1.9 million new cases and 600,000 deaths predicted to occur in 2023 [1]. Medical professionals and scientists have developed several techniques and procedures to combat this disease including gene therapies, surgeries, and chemotherapies. Several of these techniques incorporate the use of pulsed electric fields to deliver molecular material to treat, or directly destroy, the cells of the tumor. These pulsed electric field techniques are known as gene electrotransfer, electrochemotherapy, and irreversible electroporation. All three techniques utilize different electrical parameters to achieve their target tumor reduction or expression goals. Efforts to …

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 …

Pulsed Electric Field Ablation Of Esophageal Malignancies And Mitigating Damage To Smooth Muscle: An In Vitro Study, Emily Gudvangen, Uma Mangalanathan, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Andrei G. Pakhomov

Bioelectrics Publications

Cancer ablation therapies aim to be efficient while minimizing damage to healthy tissues. Nanosecond pulsed electric field (nsPEF) is a promising ablation modality because of its selectivity against certain cell types and reduced neuromuscular effects. We compared cell killing efficiency by PEF (100 pulses, 200 ns–10 µs duration, 10 Hz) in a panel of human esophageal cells (normal and pre-malignant epithelial and smooth muscle). Normal epithelial cells were less sensitive than the pre-malignant ones to unipolar PEF (15–20% higher LD50, p < 0.05). Smooth muscle cells (SMC) oriented randomly in the electric field were more sensitive, with 30–40% lower LD50 (p < 0.01). Trains of ten, 300-ns pulses at 10 kV/cm caused twofold weaker electroporative uptake of YO-PRO-1 dye in normal epithelial cells than in either pre-malignant cells or in SMC oriented perpendicularly to the field. Aligning SMC with the field reduced the dye uptake fourfold, along with a twofold reduction in Ca²⁺ transients. A 300-ns pulse induced a twofold smaller transmembrane potential in cells aligned with the field, making them …

Identification Of Proteins Involved In Cell Membrane Permeabilization By Nanosecond Electric Pulses (Nsep), Giedre Silkuniene, Uma Mangalanathan, Alessandra Rossi, Peter A. Mollica, Andrei G. Pakhomov, Olga N. Pakhomova

Bioelectrics Publications

The study was aimed at identifying endogenous proteins which assist or impede the permeabilized state in the cell membrane disrupted by nsEP (20 or 40 pulses, 300 ns width, 7 kV/cm). We employed a LentiArray CRISPR library to generate knockouts (KOs) of 316 genes encoding for membrane proteins in U937 human monocytes stably expressing Cas9 nuclease. The extent of membrane permeabilization by nsEP was measured by the uptake of Yo-Pro-1 (YP) dye and compared to sham-exposed KOs and control cells transduced with a non-targeting (scrambled) gRNA. Only two KOs, for SCNN1A and CLCA1 genes, showed a statistically significant reduction in …

Nonviral Approaches For Delivery Of Crispr-Cas9 Into Hepatocytes For Treatment Of Inherited Metabolic Disease, Tanner R. Rathbone

All Dissertations

Inherited metabolic diseases (IMDs) of the liver have a collective occurrence of about 1 in 800 births. Current therapies for IMDs of the liver are limited, and the only curative option for patients is orthotopic liver transplantation. Due to shortages of organ donors, immunosuppression following the transplantation, and mortality risks associated with the procedure, alternative treatment options are necessary for curing IMDs of the liver. Therapeutic gene editing has been proposed as a potential strategy for treating IMDs of the liver. Adeno-associated viral vectors (AAVs) are the most widely used delivery method for liver-targeted gene therapies. Although widely used for …

Electroporation And Cell Killing By Milli- To Nanosecond Pulses And Avoiding Neuromuscular Stimulation In Cancer Ablation, Emily Gudvangen, Vitalii Kim, Vitalij Novickij, Federico Battista, Andrei G. Pakhomov

Bioelectrics Publications

Ablation therapies aim at eradication of tumors with minimal impact on surrounding healthy tissues. Conventional pulsed electric field (PEF) treatments cause pain and muscle contractions far beyond the ablation area. The ongoing quest is to identify PEF parameters efficient at ablation but not at stimulation. We measured electroporation and cell killing thresholds for 150 ns–1 ms PEF, uni- and bipolar, delivered in 10- to 300-pulse trains at up to 1 MHz rates. Monolayers of murine colon carcinoma cells exposed to PEF were stained with YO-PRO-1 dye to detect electroporation. In 2–4 h, dead cells were labeled with propidium. Electroporation and …

Atmospheric Air Plasma Streamers Deliver Nanosecond Pulses For Focused Electroporation, Shu Xiao, Carol Zhou, Eric Appia, Shirshak Dhali

Bioelectrics Publications

Background: For electrotherapies that involve electrodes and high-intensity electric fields, such as in tissue ablation, we report a method of pulse delivery that can focus the electric field away from the electrodes, as demonstrated in vitro.

Materials and Methods: To electroporate cells in a monolayer seeded in a 35 mm culture dish, two atmospheric-pressure plasma channels generated by two thin, copper foil electrodes above the surface of the solution provided the current and established the electric field.

Results: Depending on the pulse duration, the plasma channels were observed as corona (100 ns), streamer (300 ns), and mixture of streamer …

Molecular Dynamics Simulations Of Ion Transport Through Electrically Stressed Biological Membranes, Federica Castellani

Biomedical Engineering Theses & Dissertations

The cell membrane is a selectively permeable barrier that controls the transport of ions, molecules, and other materials into and out of a cell. The manipulation of the cell membrane permeability is the basis for several biotechnological and biomedical applications, including electroporation. Electroporation (or electropermeabilization) occurs when the application of an external electric pulse causes water intrusion into the membrane interior and the formation of conductive transmembrane electropores. These electropores allow drugs, genetic material, and other normally impermeant molecules to enter a cell. Despite years of study, the complex mechanisms underlying this process are still not well understood. Molecular dynamics …

Moderate Heat-Assisted Gene Electrotransfer For Intradermal Dna Vaccination And Protein Replacement Therapy In The Skin, Chelsea Marie Edelblute

Biomedical Sciences Theses & Dissertations

Gene electrotransfer (GET) holds great promise for the delivery of therapeutic agents. The skin serves as an attractive target for GET due to its availability and unique cellular composition. Protein replacement therapy and DNA vaccination are potential applications for intradermal GET. The combination of moderate tissue preheating and GET has been shown to achieve elevated gene expression levels while reducing the necessary applied voltage. In the current work, we utilized a 16-pin multi-electrode array (MEA) and incorporated nine optical fibers, connected to an infrared laser, to pre-heat the tissue to 43°C before application of GET. In a guinea pig model, …

Moderate Heat-Assisted Gene Electrotransfer As A Potential Delivery Approach For Protein Replacement Therapy Through The Skin, Chelsea Edelblute, Cathryn Mangiamele, Richard Heller

Bioelectrics Publications

Gene-based approaches for protein replacement therapies have the potential to reduce the number of administrations. Our previous work demonstrated that expression could be enhanced and/or the applied voltage reduced by preheating the tissue prior to pulse administration. In the current study, we utilized our 16-pin multi-electrode array (MEA) and incorporated nine optical fibers, connected to an infrared laser, between each set of four electrodes to heat the tissue to 43 °C. For proof of principle, a guinea pig model was used to test delivery of reporter genes. We observed that when the skin was preheated, it was possible to achieve …

Moderate Heat-Assisted Gene Electrotransfer For Cutaneous Delivery Of A Dna Vaccine Against Hepatitis B Virus, Chelsea Edelblute, Cathryn Mangiamele, Richard Heller

Bioelectrics Publications

An estimated 350 million people are living with chronic Hepatitis B virus (HBV) worldwide. Preventative HBV vaccination in infants has reduced the disease burden; however, insufficient immunization programs and access obstacles leave vulnerable populations at risk for infection in endemic regions. Gene electrotransfer (GET) using a noninvasive multielectrode array (MEA) provides an alternative platform for DNA vaccination in the skin. DNA vaccines are nonlive and nonreplicating and temperature stable unlike their counterparts. In addition, their simple engineering allows them to be manufactured quickly at a low cost. In the current work, we present the combination of GET and moderate heating …

Electroporation Safety Factor Of 300 Nanosecond And 10 Millisecond Defibrillation In Langendorff-Perfused Rabbit Hearts, Johanna U. Neuber, Andrei G. Pakhomov, Christian W. Zemlin

Bioelectrics Publications

Aims

Recently, a new defibrillation modality using nanosecond pulses was shown to be effective at much lower energies than conventional 10 millisecond monophasic shocks in ex vivo experiments. Here we compare the safety factors of 300 nanosecond and 10 millisecond shocks to assess the safety of nanosecond defibrillation.

Methods and results

The safety factor, i.e. the ratio of median effective doses (ED50) for electroporative damage and defibrillation, was assessed for nanosecond and conventional (millisecond) defibrillation shocks in Langendorff-perfused New Zealand white rabbit hearts. In order to allow for multiple shock applications in a single heart, a pair of needle electrodes …

Secretion Of Proteins And Antibody Fragments From Transiently Transfected Endothelial Progenitor Cells, Loree Heller, Reynald Thinard, Melanie Chevalier, Sezgi Arpag, Yu Jing, Ruth Greferath, Richard Heller, Claude Nicolau

Bioelectrics Publications

In neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis and amyotrophic lateral sclerosis, neuroinflammation can lead to blood-brain barrier (BBB) breakdown. After intravenous or intra-arterial injection into mice, endothelial progenitor cells (EPCs) home to the damaged BBB to promote neurovascular repair. Autologous EPCs transfected to express specific therapeutic proteins offer an innovative therapeutic option. Here, we demonstrate that EPC transfection by electroporation with plasmids encoding the reporter protein GFP or an anti-beta-amyloid antibody fragment (Fab) leads to secretion of each protein. We also demonstrate the secreted anti-beta-amyloid Fab protein functions in beta-amyloid aggregate solubilization.

Probing Nanoelectroporation And Resealing Of The Cell Membrane By The Entry Of Ca2+ And Ba2+ Ions, Wenfei Bo, Mantas Silkunas, Uma Mangalanathan, Vitalij Novickij, Maura Casciola, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

The principal bioeffect of the nanosecond pulsed electric field (nsPEF) is a lasting cell membrane permeabilization, which is often attributed to the formation of nanometer-sized pores. Such pores may be too small for detection by the uptake of fluorescent dyes. We tested if Ca²⁺, Cd²⁺, Zn²⁺, and Ba²⁺ ions can be used as nanoporation markers. Time-lapse imaging was performed in CHO, BPAE, and HEK cells loaded with Fluo-4, Calbryte, or Fluo-8 dyes. Ca²⁺ and Ba²⁺ did not change fluorescence in intact cells, whereas their entry after nsPEF increased fluorescence within <1 ms. The threshold for one 300-ns pulse was at 1.5–2 kV/cm, much lower than >7 …

Impedance Analysis Of Tissues In Nspef Treatment For Cancer Therapy, Edwin Ayobami Oshin

Biomedical Engineering Theses & Dissertations

Nanosecond pulsed electric field (nsPEF) for cancer therapy is characterized by applications of high voltage pulses with low pulsed energy to induce non-thermal effects on tissues such as tumor ablation. It nonthermally treats tissues via electroporation. Electroporation is the increase in permeabilization of a cell membrane due to the application of high pulsed electric field. The objective of this study was to investigate the effect of nsPEF on tissue by monitoring the tissue’s impedance in real-time. Potato slices (both untreated and electroporated), and tumors extracted from female BALBc mice were studied. 100ns, 1-10kV pulses were applied to the tissues using …

The Combined Effect Of Heat And Corona Charge On Molecular Delivery To A T-Cell Line In-Vitro, Molly A. Skinner

USF Tampa Graduate Theses and Dissertations

Gene therapy and immunotherapy are new up and coming fields in cancer treatment. In August of 2017, the first gene therapy was FDA approved called CAR-T cell therapy("FDA approval brings first gene therapy to the United States," 2017). This therapy uses the patient’s

own T-cells that are genetically modified to attack the cancerous cells. Currently, it takes 4-6 weeks to genetically modify these T-cells, which can be the difference between life and death for a cancer patient (Cheng, Jun, Jiang, & Xi, 2017). There is evidence that gene electrotransfer can help expedite the genetic modification process by having an easy …

Initiation Of Action Potential In Murine Ventricular Myocytes By Bursts Of Nanosecond Pulses, Iurii Semenov

Bioelectrics Publications

[First slide] Current situation

I. Among 300,000 persons die from sudden cardiac arrest every year over 40% are victims of fibrillation

II. Defibrillation by an electric shock is the effective therapy against sudden cardiac death

III. Current approach to stop fibrillation may involve disruption of plasma membrane (PM) by an electroporation

IV. Electroporation is damaging, it can: I. Induce post shock arrhythmias II. Complicate patient's recovery III. Lead to death after initially successful resuscitation

Intratumoral Delivery Of Plasmid Il12 Via Electroporation Leads To Regression Of Injected And Noninjected Tumors In Merkel Cell Carcinoma, Shailender Bhatia, Natalie V. Longino, Natalie J. Miller, Rima Kulikauskas, Jayasri G. Iyer, Dafina Ibrani, Astrid Blom, David R. Byrd, Upendra Parvathaneni, Christopher Twitty, Jean S. Campbell, Mai H. Le, Sharron Gargosky, Robert H. Pierce, Richard Heller, Adil Daud, Paul Nghiem

Bioelectrics Publications

Purpose: Interleukin-12 (IL12) promotes adaptive type I immunity and has demonstrated antitumor efficacy, but systemic administration leads to severe adverse events (AE), including death. This pilot trial investigated safety, efficacy, and immunologic activity of intratumoral delivery of IL12 plasmid DNA (tavo) via in vivo electroporation (i.t.-tavo-EP) in patients with Merkel cell carcinoma (MCC), an aggressive virus-associated skin cancer.

Experimental Design: Fifteen patients with MCC with superficial injectable tumor(s) received i.t.-tavo-EP on days 1, 5, and 8 of each cycle. Patients with locoregional MCC (cohort A, N = 3) received one cycle before definitive surgery in week 4. …

Moderate Heat Application Enhances The Efficacy Of Nanosecond Pulse Stimulation For The Treatment Of Squamous Cell Carcinoma, Chelsea M. Edelblute, Sigi Guo, Embo Yang, Chunqi Jiang, Karl Schoenbach, Richard Heller

Bioelectrics Publications

Nanosecond pulse stimulation as a tumor ablation therapy has been studied for the treatment of various carcinomas in animal models and has shown a significant survival benefit. In the current study, we found that moderate heating at 43°C for 2 minutes significantly enhanced in vitro nanosecond pulse stimulation-induced cell death of KLN205 murine squamous cell carcinoma cells by 2.43-fold at 600 V and by 2.32-fold at 900 V, as evidenced by propidium iodide uptake. Furthermore, the ablation zone in KLN205 cells placed in a 3-dimensional cell-culture model and pulsed at a voltage of 900 V at 43°C was 3 times …

Asymmetric Patterns Of Small Molecule Transport After Nanosecond And Microsecond Electropermeabilization, Esin B. Sözer, C. Florencia Pocetti, P. Thomas Vernier

Bioelectrics Publications

Imaging of fluorescent small molecule transport into electropermeabilized cells reveals polarized patterns of entry, which must reflect in some way the mechanisms of the migration of these molecules across the compromised membrane barrier. In some reports, transport occurs primarily across the areas of the membrane nearest the positive electrode (anode), but in others cathode-facing entry dominates. Here we compare YO-PRO-1, propidium, and calcein uptake into U-937 cells after nanosecond (6 ns) and microsecond (220 µs) electric pulse exposures. Each of the three dyes exhibits a different pattern. Calcein shows no preference for anode- or cathode-facing entry that is detectable with …