Nowak Ewelina, Wisła-Świder Anna, Khachatryan Gohar, Fiedorowicz Maciej, Danel Krzysztof
Department of Chemistry, University of Agriculture, 122 Balicka Str., 30-149, Cracow, Poland.
Eur Biophys J. 2019 May;48(4):371-381. doi: 10.1007/s00249-019-01367-2. Epub 2019 Apr 19.
Although much research has been performed on DNA complexes carrying long alkyl chains (C10, C16, and C18), there is no information about physicochemical characterization of synthesized composites with allyl imidazole-based ionic liquids and quaternary ammonium salts with n-butyl chains. Here, complexes were synthesized by ion-exchange reactions between sonicated DNA and three ionic liquids (ILs) formed from two imidazole-based compounds, 1-allyl-3-methylimidazolium bromide (Amim) or 1-butyl-3-methylimidazolium bromide (Bmim), and from the quaternary ammonium salt tetra-n-butylammonium bromide (TBAB). Signals in UV-Vis, IR, and CD spectra indicating inclusion of small molecules into the DNA structure confirmed the formation of DNA complexes. Both IR and CD spectra indicated that the B-form conformation of the DNA did not change after the formation of the complexes. Similarly, X-ray diffraction patterns revealed that the formation of IL-DNA complexes did not change the structure of native B-form DNA. Molecular weight (M) and radii of gyration (R) values of IL-DNA complex chains, established by high-performance size exclusion chromatography coupled with multiangle-laser light-scattering with a differential refractive index detector, were significantly lower than those values found for native DNA molecules due to DNA fragmentation by sonication during complex formation and the direct effects of the IL on the DNA. Scanning electron microscopy images indicate the formation of nanofibres in DNA-Amim and DNA-Bmim complexes, whereas the formation of nanowires was found in samples of DNA-TBAB complexes. Changes in optical properties confirmed by UV and photoluminescence make DNA-IL complexes potential candidates for biosensor application.
尽管已经对携带长烷基链（C10、C16和C18）的DNA复合物进行了大量研究，但关于由烯丙基咪唑基离子液体和具有正丁基链的季铵盐合成的复合材料的物理化学特性尚无相关信息。在此，通过超声处理的DNA与由两种咪唑基化合物1-烯丙基-3-甲基咪唑溴化物（Amim）或1-丁基-3-甲基咪唑溴化物（Bmim）以及季铵盐四正丁基溴化铵（TBAB）形成的三种离子液体（ILs）之间的离子交换反应合成了复合物。紫外可见光谱、红外光谱和圆二色光谱中表明小分子被纳入DNA结构的信号证实了DNA复合物的形成。红外光谱和圆二色光谱均表明，复合物形成后DNA的B型构象未发生变化。同样，X射线衍射图谱显示，IL-DNA复合物的形成并未改变天然B型DNA的结构。通过高效尺寸排阻色谱结合多角度激光光散射和示差折光检测器确定的IL-DNA复合链的分子量（M）和回转半径（R）值，由于复合物形成过程中超声处理导致的DNA片段化以及IL对DNA的直接作用，显著低于天然DNA分子的值。扫描电子显微镜图像表明在DNA-Amim和DNA-Bmim复合物中形成了纳米纤维，而在DNA-TBAB复合物样品中发现形成了纳米线。紫外和光致发光证实的光学性质变化使DNA-IL复合物成为生物传感器应用的潜在候选物。
