Christian Doppler Laboratory for Monitoring of Microbial Contaminants , University of Veterinary Medicine , Veterinaerplatz 1 , 1210 Vienna , Austria.
Proionic GmbH , Parkring 18 , 8074 Grambach , Austria.
ACS Comb Sci. 2019 Feb 11;21(2):90-97. doi: 10.1021/acscombsci.8b00141. Epub 2019 Jan 7.
Over the past decades, ionic liquids (ILs) have gained considerable attention from the scientific community because of their versatile and designable properties. As a result, there are numerous IL applications, not only in organic synthesis, catalysis, or extraction but also as active pharmaceutical ingredients or novel antimicrobials. While considerable effort has been put into developing quantitative structure-activity relationship (QSAR) models for IL toxicity prediction, little is known about their actual mode of action. In this study, Fourier transform infrared (FTIR) spectroscopy is used to monitor IL induced molecular responses directly at the cellular level. Investigation of the well-known cationic alkyl side-chain effect (increasing side-chain length leads to increasing toxicity) of imidazolium- and ammonium-based ILs on two bacterial pathogens, enteropathogenic Escherichia coli (EPEC) and methicillin-resistant Staphylococcus aureus (MRSA), surprisingly revealed two distinct modes of action. Contrary to prior models, it was only for [TMCA][Cl], where a molecular response in the membrane was found, while ILs with shorter side-chain lengths predominantly affected bacterial proteins. The results of this study highlight the importance of further direct investigations of the impact of ILs at the cellular level to improve toxicity prediction and assess the usefulness of spectroscopic methods, such as FTIR spectroscopy at achieving this goal.
在过去的几十年中，由于离子液体（ILs）具有多样且可设计的特性，因此引起了科学界的广泛关注。因此，IL 有许多应用，不仅在有机合成、催化或提取中，而且还作为活性药物成分或新型抗菌剂。尽管已经投入了相当大的精力来开发用于预测 IL 毒性的定量构效关系（QSAR）模型，但对于它们的实际作用模式却知之甚少。在这项研究中，傅里叶变换红外（FTIR）光谱用于直接在细胞水平上监测 IL 引起的分子反应。对两种细菌病原体，肠致病性大肠杆菌（EPEC）和耐甲氧西林金黄色葡萄球菌（MRSA）的基于咪唑鎓和铵的 IL 的阳离子烷基侧链效应（侧链长度增加导致毒性增加）的研究结果令人惊讶地揭示了两种截然不同的作用模式。与先前的模型相反，只有在[TMCA][Cl]中，才发现了膜中的分子反应，而具有较短侧链长度的 IL 主要影响细菌蛋白。这项研究的结果强调了在细胞水平上进一步直接研究 IL 影响以改善毒性预测并评估光谱方法（如 FTIR 光谱）在实现这一目标中的有用性的重要性。
