The plasma membrane voltage ( V m ) is well known to have significant involvement in a wide range of cellular functions including cancer progression. Voltage imaging revealed that V m of MDA-MB-231 breast cancer cells is “bistable” with hyperpolarizing voltage transients (HVTs). Here, we formulate a model of V m incorporating the ion channels N a v 1.5 , C a v 3.2 , and K Ca 1.1 . V m is governed by the Hodgkin–Huxley formalism coupled to intracellular C a 2 + dynamics, via C a 2 + influx through C a v 3.2 and C a 2 + -dependent efflux of K + through K Ca 1.1 . Stochastic fluctuations—arising from sparse ion channel expression and C a 2 + -induced C a 2 + release (CICR)—drive V m transitions between the otherwise stable depolarized and hyperpolarized states. The model qualitatively reproduces the key experimental observations of HVTs, and their suppression by specific inhibitors of N a v 1.5 or K Ca 1.1 . It is predicted that inhibition of CICR should also lead to suppression of HVTs. Our model promises to help the understanding of the dynamic electrical activity of the MDA-MB-231 cell model and its functional consequences, and may inspire future bioelectricity-based cancer diagnosis and therapy.

There is a large body of research on the iron storage protein ferritin, which mostly concerns how it stores and releases iron and interacts with the labile iron pool of a cell. A smaller amount of research concerns the unusual physical properties of ferritin, such as how it chemically interacts with compounds that are found in cells, how it can be used as a template for nanoparticles, how it can be loaded with chemotherapy drugs to treat cancer, and how it can be used as a contrast agent for magnetic resonance imaging and its bulk electric and magnetic properties. Only recently have the electrical and magnetic properties of individual particles of ferritin been studied, and those are very different from the bulk properties. This article presents an interdisciplinary review of literature from the chemical, solid state, and biological sciences and proposes hypotheses regarding how the electrical and magnetic properties of individual particles of ferritin may interact with cells and cellular systems. This evidence indicates that those properties are a factor in serious diseases and disorders that could be prevented, treated, or possibly cured if those properties were better understood.

Irreversible electroporation (IRE) has been explored significantly for health care applications, especially cancer therapy and wound healing. It is associated with massive cell death via the bursting of cells caused by the creation of nanopores due to the rapid alteration of a voltage gradient across the cell membrane. It is reported to disinfect chronic wounds and burn injuries, minimize scar tissue formation, and regenerate accessory organs like hair follicles. However, several theories surround this therapy’s efficacy, such as the activation of immune pathways via paracrine secretion. The current study used a keratinocyte cell line (HaCaT) monolayer as an in vitro model to explore the significant immediate side effects of applying IRE. IRE was applied to cellular monolayers via needle electrodes as bursts of pulsed electric field (PEF). We observed via microscopic image analysis that there were input voltage-dependent alterations in cellular monolayer morphology visible in both phase contrast and using fluorescent live/dead staining. Similar changes were observed in reactive oxygen species-specific staining, mitochondrial membrane potential-specific staining, and cell membrane lipid peroxidation-specific staining. All the micrographic imaging showed that the affected area was highly correlated with the input voltage. Furthermore, a multiphysics simulation of the IRE applied to the cellular monolayer for an individual pulse was performed to characterize the electric field intensity spatial distribution. It exhibited similarities with the morphological alteration profiles in the cellular monolayer post-PEF application. We also found multinucleated or fused cells outside the IRE-induced immediate death zone, which could also be another side effect of this exposure.

The electroporation phenomenon is not yet fully understood. In particular, it remains unclear why cell membrane permeability, as indicated by impedance measurements, continues to increase during electric field exposure and why elevated permeability persists long after the field has been removed. This study conducts a numerical investigation to determine whether Joule heating, which is expected to be intense within the pores formed during electroporation, can produce temperature increases sufficient to locally affect the structural integrity of the cell membrane, potentially serving as a contributing mechanism. To achieve this, an electroporated cell membrane patch containing one or more pores was modeled using the finite element method. The study first simulated the dynamic temperature increase resulting from the application of a 100 µs square electric pulse. Subsequently, static temperature distributions, corresponding to permanent field exposures, were analyzed as a function of pore size, geometry, and density to explore their influence on temperature elevation. The results indicate that the temperature increases are minimal (<0.1 K) and negligible with respect to membrane disruption, suggesting that Joule heating within pores is very unlikely to contribute to the electroporation phenomenon.

Introduction: Pulsed electric field (PEF) technology shows promise for microbial control in biorefinery applications. However, its effectiveness in mixed cultures remains poorly understood. This study investigated the differential effects of PEF treatment on bacterial inactivation and algal protein preservation in a coculture of Chlorella vulgaris algae and Delftia sp. bacteria. Methods: Algal and bacterial viable cell counts and viability were quantified using flow cytometry with differential fluorescent staining (SYTO 9, YO-PRO-1, fluorescein diacetate [FDA]), bacterial growth was monitored spectrophotometrically at 600 nm, protein extraction was determined by modified Lowry assay, protein profiles analyzed by SDS-PAGE, and extract antimicrobial activity was assessed by agar diffusion and growth inhibition assays. We compared PEF treatments at two energy levels (4 and 100 J/mL) against high-pressure homogenization (HPH) as a control, with assessments at different growth phases (days 1, 3, and 7). Results: While PEF consistently inactivated >95% of algal cells, regardless of the growth phase, bacterial inactivation varied significantly, with maximum susceptibility on day 3 (70–80% mortality) when bacteria entered the starvation phase. Unexpectedly, on day 7, PEF treatment of cocultures led to bacterial proliferation, with viable counts increasing up to 4-fold compared with untreated controls. Analysis of algal extracts showed no antimicrobial activity against bacteria, and instead supported bacterial proliferation, suggesting that cellular disruption releases compounds that can be metabolized by surviving bacteria. Furthermore, while PEF preserved the integrity of algal protein profiles regardless of bacterial presence, HPH treatment of cocultures introduced a novel ∼27 kDa protein band, suggesting bacterial contamination of the extract. Conclusion: These findings reveal the complex, growth phase-dependent dynamics inherent in PEF treatment of mixed microbial systems and provide critical insights into biorefinery applications in which microbiological control and product quality must be balanced.

Electrical stimulation has expanded beyond excitable tissues, with bioelectronic medicine exploring new therapeutic avenues. We propose a novel paradigm: continuously repeated electroporation to induce controlled Ca 2+ influx and modulate cellular functions. Given the central role of Ca 2+ as a second messenger tightly regulated by homeostatic mechanisms, transient permeabilization via electric fields enables perturbation of intracellular Ca 2+ dynamics, influencing processes such as proliferation, differentiation, metabolism, and cell death. We define “MILD electroporation” as a process involving prolonged or repetitive mild membrane permeabilization induced by electric fields that facilitates calcium entry without causing direct cell death. At 5 th World Congress on Electroporation and Pulsed Electric Fields in Biology, Medicine, and Food & Environmental Technologies, we presented in vitro evidence showing that specific electric field waveforms elicit Ca 2+ oscillations in stem cells, modulating gene expression and promoting proliferation. We also presented preliminary results suggesting that burst-modulated alternating fields may slow cancer cell proliferation.

Introduction: Electrochemotherapy is an established treatment for primary and secondary cutaneous tumors of various histologies, combining chemotherapy with the delivery of high-voltage electric pulses to enhance drug uptake. Electric pulses induce water electrolysis, leading to extreme pH changes around the electrodes—acid at the anode and base at the cathode—causing tissue damage and contributing to a self-sterilizing effect, but also promoting needle corrosion. These pH shifts depend on pulse parameters, electrode geometry, and the surrounding medium; although natural tissue buffers can mitigate them, neutralization is often incomplete. This work analyzes the effect of pH changes on needle deterioration during pulse delivery. Materials and Methods: Needle electrodes were inserted into an ex vivo tissue model and subjected to eight 100 µs monopolar pulses of 1,000 V/cm at 5,000 Hz. Every 50 trains, electrodes were inserted into a gel with a pH indicator, and a single pulse was delivered to visualize nonconducting areas. Electrode surfaces were photographed, and COMSOL simulations analyzed electric field variations due to isolated regions. Electrodes were then sanded to assess if removing corrosion restored conductivity. In addition, a buffered gel was developed to reduce corrosion. Results: New needles showed significant conductivity loss after 50 trains and were almost completely isolated after 150 trains. While this suffices for treating most tumors, extensive treatments requiring over 300 trains demand electrode replacement before reaching 150 trains. Sanding temporarily restores conductivity, but sanded electrodes corrode more rapidly, losing effectiveness after fewer than 50 additional trains. A specifically designed buffered gel improved electrode durability by maintaining conductivity and could help minimize skin side effects.