Study on the Conformation of Entrapped Protein inside the Reverse Micellar Confinement Based on the Amino Acid Derived Ionic Liquid

Abstract

AbstractOwing to superior surface‐activity and versatility in functionalization compared to conventional surfactants, surface‐active ionic liquids (SAILs) gained immense interest in recent years. Toxicity and biodegradation remain central issues while dealing with the SAILs and thus, the quest for synthesis of greener SAILs is increasing day by day. Keeping in view of the importance of SAIL's performance, we undertook the present study for the formulation of reverse micelles (RMs) using biodegradable L‐proline propyl ester lauryl sulfate ([ProC3][LS]) in cyclohexane (Cy). The formation of RMs was confirmed from the phase behavior and dynamic light scattering (DLS) studies. Fourier‐transform infrared spectroscopy (FTIR) study revealed the solvation of anionic head group through H‐bonding by added water. An increased micropolarity and reduced microviscosity were evidenced inside the RM droplets as a function of hydration level. Finally, the encapsulation of BSA protein in RMs was investigated through the fluorescence, circular dichroism and DLS studies, which showed conformation with higher degree of secondary structural content than the native state inside the droplet core at higher hydration. Our results signify the importance of the role of hydration in the function of enzyme or protein molecules in molecular crowding environments. These facts certainly prove the versatility of this kind of organized assemblies to alter their inherent properties simply by changing water content.