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.

A high-intensity pulsed magnetic field generator, as a high-power pulsed current generator with inductive loads, can be used in transcranial magnetic stimulation, tumor therapy, and so on. This article presents a new type of pulse generator called the Marx-based modular energy-saving pulse generator (MEPG) that can improve the output performance of conventional pulsed magnetic field generators in the biomedical field. The MEPG includes a front-end energy-feeding circuit and a series of discharging modules at different levels. It can regulate the current of inductive coils, which in turn controls the magnetic field output from the coils. The MEPG incorporates a commutator switch and energy-feeding diode in the front-end circuit, facilitating the feedback of load energy to capacitors at all levels. The MEPG offers flexible adjustment of the output current change rate by controlling the switching sequence of the discharge modules. Moreover, the amplitude of the output current can be fine-tuned by adjusting the switching on time or capacitor voltages at different levels. The converter switch’s opening and closing at the discharge end corresponds to the two distinct output modes: exponential wave and triangular wave pulsed current. To assess the MEPG’s output performance and energy recovery efficiency, a three-stage MEPG system was constructed. The coil was subjected to pulse currents of different amplitudes and pulse widths in both simulations and measurements, revealing the platform’s excellent energy recovery efficiency. Finally, we demonstrated that the MEPG possesses a versatile output functionality by outputting a set of customized pulse current waveforms in the coil.

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.

The biological response to short pulses with a width on the order of ten nanoseconds is still blur for lacking of a dependable high-voltage ultrashort pulse power module (HVUPPM). Therefore, this article introduces a HVUPPM with high output/input voltage gain and high repetition rates. First, the proposed HVUPPM utilizes a short-circuit secondary side transformer (SSST) as an intermediate energy storage component and generates high-voltage nanosecond pulses based on inductive energy storage. Analyzed the impact of parasitic parameters on waveforms and verified the analysis results through simulation. Secondly, in order to further improve the output voltage, a twisted pair transformer (TPT) with low leakage inductance is used as the power superposition element of HVUPPM to increase the output voltage amplitude and suppress waveform distortion. Finally, a prototype was developed to verify the functionality of the proposed HVUPPM and TPT. The prototype can output pulses with a half-peak width of 13 ns and an amplitude of 5.2 kV, achieving an output/input voltage gain of 400. In burst mode, it can generate unipolar pulses with a repetition frequency of up to 2 MHz and bipolar pulses with repetition rates in the MHz range.

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.