School of Electrical Engineering, Shandong University, Jinan 250061, China.
Molecules. 2023 May 1;28(9):3850. doi: 10.3390/molecules28093850.
The abuse of tetracycline antibiotics (TCs) has caused serious environmental pollution and risks to public health. Degradation of TCs by cold atmospheric plasmas (CAPs) is a high efficiency, low energy consumption and environmentally friendly method. In this study, a reactive molecular dynamics (MD) simulation is applied to study the interactions of reactive oxygen species (ROS) produced in CAPs and TCs (including tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC) and demeclocycline (DMC)). As revealed by the simulation data at the atomic level, the main reaction sites on TCs are the C2 acylamino, the C4 dimethylamine, the C6 methyl group, the C8 site on the benzene ring and the C12a tertiary alcohol. The interaction between ROS and TCs is usually initiated by H-abstraction, followed by the breaking and formation of the crucial chemical bonds, such as the breaking of C-C bonds, C-N bonds and C-O bonds and the formation of C=C bonds and C=O bonds. Due to the different structures of TCs, when the ROS impact OTC, CTC and DMC, some specific reactions are observed, including carbonylation at the C5 site, dechlorination at the C7 site and carbonylation at the C6 site, respectively. Some degradation products obtained from the simulation data have been observed in the experimental measurements. In addition, the dose effects of CAP on TCs by adjusting the number of ROS in the simulation box are also investigated and are consistent with experimental observation. This study explains in detail the interaction mechanisms of degradation of TCs treated by CAPs with the final products after degradation, provides theoretical support for the experimental observation, then suggests optimization to further improve the efficiency of degradation of TCs by CAPs in applications.
四环素类抗生素（TCs）的滥用导致了严重的环境污染和对公众健康的威胁。冷等离子体（CAPs）降解 TCs 是一种高效、低能耗且环保的方法。在这项研究中，应用反应分子动力学（MD）模拟研究了 CAPs 中产生的活性氧物种（ROS）与 TCs（包括四环素（TC）、土霉素（OTC）、金霉素（CTC）和去甲金霉素（DMC））的相互作用。从原子水平的模拟数据中揭示，TCs 的主要反应位点是 C2 酰氨基、C4 二甲胺、C6 甲基、苯环上的 C8 位和 C12a 叔醇。ROS 与 TCs 的相互作用通常是由 H 抽提引发的，随后是关键化学键的断裂和形成，如 C-C 键、C-N 键和 C-O 键的断裂以及 C=C 键和 C=O 键的形成。由于 TCs 的结构不同，当 ROS 冲击 OTC、CTC 和 DMC 时，观察到一些特定的反应，包括 C5 位的羰基化、C7 位的脱氯和 C6 位的羰基化。从模拟数据中获得的一些降解产物已经在实验测量中观察到。此外，还通过调整模拟箱中 ROS 的数量研究了 CAP 对 TCs 的剂量效应，与实验观察结果一致。这项研究详细解释了 CAP 处理 TCs 的降解的相互作用机制以及降解后的最终产物，为实验观察提供了理论支持，然后建议进行优化以进一步提高 CAPs 降解 TCs 的效率。
