Bioelectricity

Sub-nanosecond pulsed electric fields (sub-nsPEFs) present a promising tool for cellular and intracellular electro-manipulation. In this article, we propose a microfluidic device based on a coplanar waveguide (CPW) for high-intensity sub-nsPEF delivery and biomedical investigations. To deliver high-intensity and ultra-short-duration pulses, the CPW device features a miniaturized gap width of 345 µm. Numerical simulations and measurements confirm that this device presents a return loss lower than −10 dB over a wide frequency bandwidth, up to 3.7 GHz. Additionally, the results demonstrate a consistent electric field homogeneity within the CPW channels, particularly in the central area where the biological samples will be exposed. The CPW-based device was characterized under high-voltage sub-nanosecond duration pulse exposure. The results evidenced that the device is suitable for the delivery of ∼18 MV/m intensity and 500 ps duration pulses.

Electroporation is a well-established technique that induces transient pores in cell membranes through intense electric fields. While previous studies have focused primarily on lipid bilayers, the role of membrane proteins in electroporation remains poorly understood. This study investigates the impact of high-intensity electric fields on the TRPV4 ion channel using molecular dynamics simulations to elucidate protein involvement in electroporation processes. The research examines two conformational states of human TRPV4 (hTRPV4, closed and inactivated) embedded in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipid bilayers in a hydrated system under electric (E-)field exposure of 50, 70, and 80 MV/m. A novel algorithm was developed to precisely identify and analyze two distinct water populations: interfacial water near membrane surfaces and channel-confined water within the TRPV4 channel. Key findings reveal fundamentally different responses between these water populations. These findings provide new mechanistic insights into protein-mediated electroporation, highlighting its potential role in electroporation-driven membrane permeabilization, and suggest opportunities for developing targeted therapeutic strategies that exploit the presence and functional state of specific transmembrane proteins in membrane permeabilization processes.

Low-energy micro- and millisecond electric pulses (EPs) charge and depolarize the cellular plasma membrane (PM) below the electroporation threshold. Conversely, individual nanosecond EPs (NSEPs) are too brief to initiate PM depolarization by charging the cells. It is hypothesized that a single NSEP induces cell depolarization via PM electroporation upon application of high-power EPs. However, low-energy NSEP bursts with a very high pulse repetition frequency may prevent electroporation. This method, a temporal summation of NSEPs, results in subsequent PM charging and depolarization. To visualize PM voltage changes during low-energy EPs, we employed optical measurements using FluoVolt™ (an organic fluorescent reporter of membrane potential [MP]) and a custom-made streak imaging system. Ultra-fast streak kymographs depicting MP changes were obtained after exposure to a ∼0.2 kV/cm single 200 µs EP and 5 MHz trains of 1000 and 2000 NSEPs with 100 ns duration. Immediately following exposure, a small FluoVolt™ response (up to ∼7% fluorescence change) was observed in the PM areas facing electrodes. The response duration directly correlated with the pulse width (PW) or duration of the NSEPs burst interval. The single 200 µs EP was more effective at charging the PM than an equivalent-energy 5 MHz burst of 2000 NSEPs of 100 ns duration. Furthermore, similar amplitudes of PM fluorescence changes between ∼0.2 kV/cm bursts of 1000 and 2000 NSEPs suggest that increasing either PW or applied voltage is necessary to enhance the extent of PM depolarization. Nonetheless, the modest depolarization effect reported herein was sufficient to open voltage-gated Ca²⁺ channels in neurons. These findings indicate that a 5 MHz burst of low-energy NSEPs and single µs EPs effectively induce PM depolarization and Ca²⁺ responses without causing any cellular damage.

Surgeons face serious challenges removing cancer fully during surgery, with incomplete cancer removal posing significant risks to patients. To address this problem, Lucell Diagnostics Inc. is developing an innovative cancer detection platform called membrane voltage profiling (MVPro; patent pending). This groundbreaking method exploits the discovery that cancer cells exhibit a physiological biomarker, depolarization, as revealed by fluorescent voltage-sensitive dyes. Cancer cells fluoresce in specific patterns and intensities that differ from normal cells, allowing precise identification. We present here our preliminary results on the feasibility of using voltage to locate cancer cells. The aims were: to perform controls showing whether MVPro affects the normal pathology process; to optimize tissue transfer for margin cell collection; to confirm that the VSD DiBAC₄(3) is appropriate for MVPro of skin cells; to determine whether MVPro finds cancer in the same specimens as pathological analysis. These studies on nonmelanoma skin cancer specimens reveal that MVPro is low risk to the patient, integrates with existing surgical protocols, finds cancer in the same specimens as does pathology, and presents no complications for pathological analysis. Once development of this methodology is complete, MVPro will yield an annotated, 2D heat map covering the entire surgical margin, indicating the location of cells with a high likelihood of being cancer. This will empower surgeons to confirm a negative surgical margin before closing. This simple type of intraoperative imaging, performed in or near the operating theater, has the potential to improve surgical outcome, cut health care costs, and enhance post-surgical quality of life by preserving healthy tissue. Because the setup costs are relatively small and the reagents are inexpensive, we believe MVPro could be of great benefit to underserved areas. Indeed, MVPro could benefit health care systems globally, from cutting-edge hospitals to small clinics in underserved regions.

Real-time electrochemical measurements of ionic fluxes and bioelectric signals are set to refine cancer diagnosis and longitudinal follow-ups with the goal of targeting electrophysiological features of clinically useful matrices. Nanoengineered electrodes translate biomolecules and ions into robust electrochemical signals for both laboratory workflows and point-of-care testing. The translational aim is to integrate electrochemical sensing into coherent, physiology-grounded readouts that resolve tumor ion channel dysfunction, membrane depolarization, pericellular acidification, and redox imbalance. Realizing this vision now depends on practical engineering and clinical integration. To advance this ongoing development, researchers are building stable, disposable, portable, and miniaturized electrochemical platforms that couple detection with microfluidics to enrich tumor cells, vesicles, and bio ionic markers for multiplexed cancer measurements. The integration of wearable and implantable systems with machine learning and patient-specific digital twins will enable real-time maps of tumor electrophysiology and model-driven forecasts of treatment response. This perspective outlines a translational roadmap for electrochemical detection of bioelectric biomarkers in cancer, wherein biomarker classes are systematically mapped to corresponding transduction strategies and mechanistic fidelity is reconciled with practical assay design constraints to identify key challenges and opportunities for advancing these technologies from foundational research to validated clinical implementation in precision oncology.

Growing insight into bioelectric regulation of cell behavior has driven extensive use of electrical stimulation in in vitro studies over the last decade, notably in the enhancement of stem cell maturation. This has prompted the development of electrical stimulation bioreactors to provide the stimulation parameters required for such studies. However, biological outcomes are highly sensitive to stimulation parameters, electrode geometry, and electrode-electrolyte interface. These are factors that current commercial and custom systems handle differently; commercial platforms are robust but often cost-prohibitive, whereas custom open-source systems are cheaper but typically lack validated, user-friendly hardware and standardization. In this perspective, we argue for openly documented electrical stimulation platforms that are not only published but also made available through open-source science manufacturers. Coupling transparent designs with distributed assembly and open validation data offers the potential to lower current barriers to entry, enabling wider adoption of pre-characterized, affordable systems that improve reproducibility and mechanistic clarity.