Studies on the Interaction of Imidazolium Ionic Liquids with Human Serum Albumin

Imidazolium-based ionic liquids have emerged as promising bio-compatible solvents for bio-molecules. The interaction of two imidazolium-based ionic liquids, namely 1-decyl-3-methyl-imidazolium tetrafluoroborate [Dmim][BF4] and 1-butyl-3-methylimidazolium octylsulfate [Bmim][OS], with human serum albumin (HSA) have been investigated using UV-visible, fluorescence and fourier transform infrared spectroscopy. Stern-Volmer quenching constant (Ksv) and the binding affinity (Ka) value have been also calculated to reveals the molecular interactions between HSA and the imidazolium-based ILs. Additionally, we explored the thermodynamic feasibility of these interactions by calculating the Gibbs free energy (∆G), entropy (∆S), and enthalpy (∆H). Hydrophobic interactions have been identified as exerting a more significant influence than hydrogen bonding in the interactions between proteins and ionic liquids. This implies that the hydrophobic characteristics of the ionic liquids play a pivotal role in the denaturation of proteins. Consequently, we conclude that the hydrophobic nature of the ionic liquids is essential for inducing interactions with proteins and potentially contributing to protein structure denaturation.