In recent years, pulsed magnetic field (PMF) have attracted significant attention as a non-invasive electroporation method in the biomedical field. To further explore the biomedical effects generated by oscillating PMF, we designed a novel PMF generator for biomedical research. Based on resonance principles, the designed generator outputs sinusoidal oscillating PMF. To validate the feasibility and application value of the designed topology, a miniaturized platform was constructed using a selected multi-turn solenoid coil. The output performance of the generator was tested under different discharge voltage levels. The results revealed that the current multiplication factor remained consistently around 2 times, with the energy efficiency and circuit quality factor maintained at 82% and above 4.5, respectively. In addition, the generator’s ability to flexibly modulate the number of pulse oscillations was demonstrated. The compatibility of the designed coil parameters and generator circuit parameters was analyzed, with tests on the effects of coil resistance and switch action time on the generator’s output performance. Based on the magnetic field action platform, a simulation model of the actual scale coil was established. The spatial and temporal distribution of the magnetic field, induced electric field, and power transmission in the target area were described from multiple angles. Finally, biological experiments conducted using the constructed generator revealed the synergistic effect of sinusoidal oscillating PMF combined with drugs in tumor cell killing.

In the irreversible electroporation (IRE) therapy, the absorbed energy is normally characterized as the applied dose and assumed to be distributed in the homogeneous dielectric. By employing statistical analyses, we have studied the absorbed energy distribution in the porous multicellular dielectric, with the geometric patterns randomly generated from the following statistical quantities: system size, cell size, cell concentration, and cell flattening ratio. Parametric formulas regarding the mean and standard deviation of the absorbed energy are obtained through numerical simulations and iterative fitting. Our statistical results reveal that the mean value of absorbed energy with cell concentration exhibits a “conductance” to “resistance” transition, similar to the percolation of two-phase materials, and the direction of the transition flips as cell diameter increases. The standard deviation of energy, however, follows a bell-shaped curve under varied concentration, indicating a shift in energy distribution from an “aggregation” to a “dispersion” state. Based on the parametric formulation, we quantitatively explore the critical threshold of the transition, as well as the general scaling laws of the geometric variables on the mean and standard deviation of the absorbed energy. Our work could help to quantitatively explain the lethality variation in IRE ablation targeting monolayer cell collectives with different geometrical characteristics.

Numerical models evaluating macroscopic pulsed electric field (PEF) efficacy typically neglect multicellular heterogeneity and assume homogeneous absorbed energy to reduce computational costs. In this Letter, through theoretical analyses from maximum information entropy methods and finite-element simulations of a realistic millimeter-scale monolayer (1393 cells in a 1 mm2 square target), we demonstrate that cellular absorbed energy universally follows a gamma distribution in response to a single pulse, remaining invariant across pulsed types, cell types, and observation scales. We propose a dimensionless heterogeneity metric h (0–1) derived from gamma distribution, to quantify local fluctuations of absorbed energy. Results show h exhibits a hyperbolic tangent dependence on the pulsed width, independent of the field strength. In vitro experiments confirm that the dimensionless h also critically governs PEF efficacy: Reduced h exponentially enhances the response rate of high-dose phase in the survival curves. Real-time fluorescence damage kinetics (169 cells) further validate the gamma-distributed energy pattern. This work uncovers spatial heterogeneity as an essential predictor for PEF efficacy, which advances the resolution setting of theoretical models for PEF efficacy prediction.

The atmospheric pressure plasma jet with a floating electrode, operated in a long-distance transfer mode, plays a key role in tumor treatment within the human body and medical device sterilization. In this work, we primarily investigate the discharge inside the dielectric tube using a self-consistent fluid model that resolves the three-phase interaction among plasma, dielectric, and floating electrode and how they modulate the secondary discharge plume. The simulation agrees well with the floating electrode voltage measured using a differential voltage probe. After breakdown, the double-headed streamer forms at the center of the discharge gap and propagates bidirectionally to cause gap conduction. The negative streamer transforms to the radial expanding surface ionization wave when impinging on the dielectric, while the positive streamer charges the floating electrode, triggering a reverse restrike that neutralizes the gap. A second discharge is then initiated at the electrode tip, launching a plasma bullet. Gap conduction causes potential redistribution between the dielectric tube and the gap, leading to a drop in floating potential. Additionally, the nonlinear dependency on the relative permittivity of the dielectric tube on multiple discharge is discussed. The high relative permittivity results in more potential distributed on the gap, and subsequent sheath space charge will suppress the discharge development and limit the floating voltage increase. This study will provide a quantitative understanding of the discharge mechanisms in long-distance plasma jets and insight into the optimization of device operation.

Pulsed electric fields (PEFs) are widely recognized as a non-thermal, selective physical therapy with wide clinical application in tumor ablation. The pulse width determines how electrical energy is distributed across plasma membrane to intracellular organelles. However, under an engineering-defined equal-dose condition (N·E²·tp), which serves as a practical control parameter rather than a measure of true cellular energy absorption, systematic and comparable experimental characterization of cellular and subcellular responses across pulse widths from the microsecond to nanosecond range remains limited. In this study, PEFs with pulse widths ranging from 100 μs to 50 ns were applied under equal-dose constraints, and cellular responses were evaluated using transmission electron microscopy (TEM), multi-organelle fluorescence imaging, and flow cytometry. The results indicate that pulse-width-dependent effects were observed under a fixed pulse-number, dose-equalized framework in which electric field strength varied across conditions. Structural and functional changes were observed in multiple organelles, including the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. Notably, nanosecond pulses were more effective in inducing mitochondrial membrane potential loss and increasing the proportion of apoptotic or non-viable cells. These findings demonstrate that, under equal-dose conditions, pulse width is a key temporal parameter governing PEF-induced biological effects, indicating that identical dose constraints do not necessarily result in equivalent biological responses. This work provides experimental foundation for parameter selection and optimization in PEF-based biomedical applications.