Biocompatibility of ionic liquids towards protein stability: A comprehensive overview on the current understanding and their implications

Over the past years since the discovery of ionic liquids (ILs), there is an increased demand to consider ILs as novel biocompatible co-solvents for proteins. Due to their tunable physical properties ILs can adjust themselves in any required experimental conditions starting from protein extraction to enzyme catalysis at elevated temperature. In recent years, large numbers of ILs have been synthesized and their effect on protein stability has been illustrated. With the rapid growth in various kinds of ILs, our understanding of protein stability in ILs has substantially increased. It is not necessary that a particular IL that is biocompatible to a protein will behave same for the other. Therefore, it is extremely essential to collect the literature dealing with the direct involvement of ILs in protein folding/unfolding studies under the same roof. This review focuses the tremendous accomplishments achieved in recent years in the field of protein stability in ILs. We hope that this would also help to set a stage where we can identify, explore and compare the mechanistic behavior of protein folding/unfolding in ILs. This review will surely bring a new boost in protein folding studies from the chemical biology perspective.