Electrochemical oxidation of proteins using ionic liquids as solubilizers, adsorption solvents and electrolytes

• Ionic liquids (ILs) based on imidazolium and ammonium cations were used.
• The proteins solubilized by ILs are adsorbable onto electrode surfaces.
• ILs can be used as electrolytes for voltammetric analysis of proteins.
• No damaging effects of ILs on the studied proteins were found.

This study focuses on application of room temperature ionic liquids (RTILs) as solubilizers, adsorption solvents and supporting electrolytes for electrochemical analysis of human and bovine serum albumins, HSA and BSA. The proteins were analyzed by ex situ, adsorptive transfer, square-wave voltammetry (SWV) at a basal-plane pyrolytic graphite electrode after solubilization using imidazolium- and ammonium-based RTILs. The application of RTILs enabled SWV scan from 0 to +1.5 V (vs. Ag/AgCl/3 M KCl) without interference with the anodic response of the proteins. Concretely, Tyr (Y) and Trp (W) oxidation currents of HSA and BSA, peak Y&W around +0.85 V, were observed and characterized under different RTILs and RTIL/water conditions. The electrochemical data were supported by electrophoresis under denaturing and native conditions. These provided evidence for the structural changes and stability of the studied proteins in the presence of RTILs. The data acquired using BSA and HSA model proteins, could be used in further applications of RTILs in protein electrochemistry and for developing new protein sensing strategies.

Figure optionsDownload as PowerPoint slide