Deoxyribonucleic acid (DNA) carries the genetic information essential for the growth and functioning of living organisms, playing a significant role in life sciences research. However, the long-term storage and preservation of DNA, while ensuring its bioactivity, are still current challenges to overcome. In this work, aqueous solutions of ionic liquids (ILs) were investigated as potential preservation media for double stranded (dsDNA). A screening of several ILs, by combining the cholinium, tetrabutylammonium, tetrabutylphosphonium, and 1-ethyl-3-methylimidazolium, cations with the anions bromide, chloride, dihydrogen phosphate, acetate, and glycolate, was carried out in order to gather fundamental knowledge on the molecular features of ILs that improve the dsDNA stability. Different IL concentrations and the pH effect were also addressed. Circular dichroism (CD) spectroscopy was used to evaluate the conformational structure and stability of dsDNA. IL-DNA interactions were appraised by UV-Vis absorption spectrophotometry and 31P nuclear magnetic resonance (NMR) spectroscopy. The results obtained demonstrate that pH has a significant effect towards the dsDNA stability. Amongst the ILs investigated, cholinium-based ILs are the most promising class of ILs to preserve the dsDNA structure, in which electrostatic interactions between the cholinium cation and the DNA phosphate groups play a significant role as demonstrated by the 31P NMR data, being more relevant at higher IL concentrations. On the other hand, the denaturation of dsDNA mainly occurs with ILs composed of more hydrophobic cations and able to establish dispersive interactions with the nucleobases environment. Furthermore, the IL anion has a weaker impact when compared to the IL cation effect to interact with DNA molecules. The experimental data of this work provide relevant fundamental knowledge for the application of ILs in the preservation of nucleic acids, being of high relevance in the biotechnology field.

中文翻译：

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关于离子液体水溶液中 DNA 稳定性的见解

脱氧核糖核酸 (DNA) 携带生物体生长和功能所必需的遗传信息，在生命科学研究中发挥着重要作用。然而，DNA 的长期储存和保存，同时确保其生物活性，仍然是当前需要克服的挑战。在这项工作中，研究了离子液体 (IL) 的水溶液作为双链 (dsDNA) 的潜在保存介质。通过将胆碱、四丁基铵、四丁基鏻和 1-乙基-3-甲基咪唑鎓阳离子与溴化物、氯化物、磷酸二氢盐、乙酸盐和乙醇酸盐的阴离子结合，对几种 IL 进行筛选，以收集有关以下方面的基础知识ILs 提高 dsDNA 稳定性的分子特征。还讨论了不同的 IL 浓度和 pH 影响。圆二色性 (CD) 光谱用于评估 dsDNA 的构象结构和稳定性。IL-DNA 相互作用通过紫外-可见吸收分光光度法和 31P 核磁共振 (NMR) 光谱法进行评估。获得的结果表明 pH 值对 dsDNA 稳定性有显着影响。在所研究的 ILs 中，基于胆碱的 ILs 是最有希望保留 dsDNA 结构的 ILs 类别，其中胆碱阳离子和 DNA 磷酸基团之间的静电相互作用起着重要作用，如 31P NMR 数据所示，更相关在较高的 IL 浓度下。另一方面，dsDNA 的变性主要发生在由疏水性更强的阳离子组成的离子液体中，并且能够与核碱基环境建立分散的相互作用。此外，与 IL 阳离子效应相比，IL 阴离子与 DNA 分子相互作用时具有较弱的影响。这项工作的实验数据为ILs在核酸保存中的应用提供了相关的基础知识，在生物技术领域具有很高的相关性。