Electroporation often leads to electrochemical reactions at the electrode-electrolytic solution interface, particularly when using monophasic pulses of considerable duration (typically on the order of several microseconds or longer) that cause not only capacitive charging of the double-layer, but also faradaic charge transfer between the electrodes and the solution. Applications, where the electrochemical changes are to be either avoided or actively exploited to benefit the treatment, range from gene electrotransfer to electrolytic ablation of tissue. Through numerical modelling and experimental validation, our study explores the extent of pH changes induced by faradaic currents in a surrogate tissue. A mechanistic multiphysics model of pH changes was developed based on first principles, incorporating hydrolysis reactions at the anode and cathode, and the Nernst-Planck model of ion transport. The model was validated using agarose gel tissue phantoms designed to simulate unbuffered and buffered (mimicking in vivo tissue buffering capacity) conditions. An imaging system with pH-sensitive dyes was developed and used to visualise and quantify pH front formation and migration. The model predictions qualitatively aligned well with experimental data, differentiating pH front behaviour between unbuffered and buffered media. However, the quantitative accuracy in predicting the temporal and spatial evolution of the pH fronts can be further improved. Experimental observations emphasise the need for more advanced models. Nevertheless, the developed model provides a sound theoretical foundation for predicting pH changes due to high-voltage electric pulse delivery, such as encountered in electroporation-based treatments and therapies.

中文翻译：

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经实验验证的电穿孔脉冲诱导的替代组织 pH 值变化的数值模型


电穿孔通常会导致电极-电解液界面处发生电化学反应，特别是当使用持续时间相当长的单相脉冲（通常为几微秒或更长时间）时，这不仅会导致双电层的电容充电，还会导致电极和溶液之间的法拉第电荷转移。避免或积极利用电化学变化以有利于治疗的应用范围从基因电转移到组织电解消融。通过数值建模和实验验证，我们的研究探索了替代组织中法拉第电流诱导的 pH 值变化的程度。基于第一性原理开发了 pH 值变化的机理多物理场模型，结合了阳极和阴极的水解反应，以及离子传输的 Nernst-Planck 模型。该模型使用琼脂糖凝胶组织模型进行了验证，该模型旨在模拟无缓冲和缓冲（模拟体内组织缓冲能力）条件。开发了一种具有 pH 敏感染料的成像系统，用于可视化和量化 pH 前沿形成和迁移。模型预测与实验数据定性一致，区分了无缓冲和缓冲介质之间的 pH 前沿行为。然而，预测 pH 前沿时间和空间演变的定量准确性可以进一步提高。实验观察强调了对更高级模型的需求。尽管如此，开发的模型为预测由于高压电脉冲传递引起的 pH 值变化提供了坚实的理论基础，例如在基于电穿孔的治疗和疗法中遇到的情况。