Cold atmospheric plasma (CAP) devices based on a plasma jet with helium flow are actively used nowadays in the studies of cancer treatment. In addition to well‐known factors produced by CAP devices (reactive chemical species, UV radiation, heat) that can reduce the viability of cancer cells, the effect of alternating continuous‐wave nonthermal electromagnetic fields generated by a plasma source inside the tissue remains unclear. In this article, we measured the values and frequency composition of the continuous‐wave electric field induced inside the model of a living tissue—a three‐dimensional artificial tissue composed of bovine type I collagen gel—during its irradiation with a helium plasma jet using the set of probes immersed into the gel. It was found that the electric field in artificial tissue has strong direct current (DC) with the main discharge frequency components, and at least up to four harmonics of the discharge frequency. The e‐field absolute values in artificial tissue during plasma treatment were within 300–30,000 V/m, which is significantly lower than the estimated cell membrane field of about ~10⁷ V/m. The absolute value of the e‐field DC component nonmonotonically depends on discharge frequency with the optimal frequency range of 14–16 kHz dependent on the thickness of the artificial tissue.

中文翻译：

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冷空气等离子体处理过程中3D胶原蛋白凝胶中连续波等离子体产生的电场

如今，基于等离子流和氦气流的冷大气等离子（CAP）设备在癌症治疗研究中得到了积极的应用。除了CAP设备产生的众所周知的因素（反应性化学物质，紫外线辐射，热量）会降低癌细胞的生存能力外，组织内部血浆源产生的交替连续波非热电磁场的影响仍然不清楚。在本文中，我们测量了在活体组织（由牛I型胶原蛋白凝胶组成的三维人工组织）的模型中用氦等离子体射流辐照期间产生的连续波电场的值和频率组成。将一组探针浸入凝胶中。已经发现，人造组织中的电场具有强的直流电（DC），其主要放电频率成分至少为放电频率的四个谐波。等离子体处理期间人造组织中的电场绝对值在300–30,000 V / m以内，这大大低于估计的约10的细胞膜场⁷  V /米。电场直流分量的绝对值非单调取决于放电频率，最佳频率范围为14–16 kHz，取决于人造组织的厚度。