Department of Chemistry, UGC Sponsored Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar-143005, India.
Phys Chem Chem Phys. 2021 Jan 6;23(1):320-328. doi: 10.1039/d0cp04513f.
Considering the remarkable applicability of ionic liquids (ILs) in bio-catalysis involving enzymes, herein, we report new IL based aqueous microemulsions as a catalytic reactor for cytochrome c (Cyt-c). Microemulsions (μEs), comprising water as the polar component, imidazolium (cation) and dioctylsulfosuccinate (AOT) (anion) based biamphiphilic ionic liquid (BAIL) as the surfactant and a hydrophobic ionic liquid (HIL) as the non-polar component have been prepared and characterized. The use of BAIL has promoted the formation of μEs without any co-surfactant, owing to its higher surface activity. The effect of ester- or amide-functionalization of the alkyl chain of the imidazolium cation of BAILs on the phase behavior of μEs has been investigated. The prepared μEs have been characterized via conductivity, dynamic light scattering (DLS), UV-vis absorption and steady-state fluorescence (using external polarity probes) techniques. The prepared μEs have been employed as nano-reactors for exploring the catalytic activity of Cyt-c. The formed BAIL-water nano-interfaces in reverse μEs have exerted a positive effect on the catalytic activity of Cyt-c stored in a water pool of reverse μEs. A five-fold higher rate constant in μEs as compared to buffer establishes μEs as a better catalytic medium. Furthermore, the differing nature of nano-interfaces created by BAILs and water in reverse μEs, depending on the functionalization of the alkyl chain of the cationic part of BAIL, has exerted varying influence on the catalytic activity of Cyt-c. It is expected that the present work will result in providing a versatile platform for the creation of new IL and water based μEs for bio-catalytic applications.
考虑到离子液体（ILs）在涉及酶的生物催化中的显著适用性，本文报道了新的基于 IL 的水包油型微乳液作为细胞色素 c（Cyt-c）的催化反应器。微乳液（μEs）由水作为极性组分、咪唑鎓（阳离子）和二辛基磺基琥珀酸钠（AOT）（阴离子）组成的双双亲性离子液体（BAIL）作为表面活性剂和疏水性离子液体（HIL）作为非极性组分制备并进行了表征。由于其更高的表面活性，BAIL 的使用促进了 μEs 的形成，而无需任何助表面活性剂。研究了 BAIL 中咪唑鎓阳离子的烷基链酯化或酰胺化对 μEs 相行为的影响。通过电导率、动态光散射（DLS）、紫外-可见吸收和稳态荧光（使用外部极性探针）技术对制备的 μEs 进行了表征。制备的 μEs 已被用作纳米反应器，以探索 Cyt-c 的催化活性。反向 μEs 中形成的 BAIL-水纳米界面对储存在反向 μEs 水相中的 Cyt-c 的催化活性产生了积极影响。与缓冲液相比，μEs 中的形成速率常数提高了五倍，这表明 μEs 是一种更好的催化介质。此外，根据 BAIL 阳离子部分的烷基链的官能化，反向 μEs 中由 BAIL 和水形成的纳米界面的性质不同，对 Cyt-c 的催化活性产生了不同的影响。预计本工作将为创建用于生物催化应用的新型 IL 和水基 μEs 提供一个多功能平台。
