Simultaneous Purification of Human Interferon Alpha-2b and Serum Albumin Using Bioprivileged Fluorinated Ionic Liquid-Based Aqueous Biphasic Systems

Abstract

Interferon alpha-2b (IFN- (Formula presented.) 2b) is an essential cytokine widely used in the treatment of chronic hepatitis C and hairy cell leukemia, and serum albumin is the most abundant plasma protein with numerous physiological functions. Effective single-step aqueous biphasic system (ABS) extraction for the simultaneous purification of IFN- (Formula presented.) 2b and BSA (serum albumin protein) was developed in this work. Effects of the ionic liquid (IL)-based ABS functionalization, fluorinated ILs (FILs; [C (Formula presented.) C (Formula presented.) Im][C (Formula presented.) F (Formula presented.) SO (Formula presented.)] and [N (Formula presented.)][C (Formula presented.) F (Formula presented.) SO (Formula presented.)]) vs. mere fluoro-containing IL ([C (Formula presented.) C (Formula presented.) Im][CF (Formula presented.) SO (Formula presented.)]), in combination with sucrose or [N (Formula presented.)][H (Formula presented.) PO (Formula presented.)] (well-known globular protein stabilizers), or high-charge-density salt K (Formula presented.) PO (Formula presented.) were investigated. The effects of phase pH, phase water content (%wt), phase composition (%wt), and phase volume ratio were investigated. The phase pH was found to have a significant effect on IFN- (Formula presented.) 2b and BSA partition. Experimental results show that simultaneous single-step purification was achieved with a high yield (extraction efficiency up to 100%) for both proteins and a purification factor of IFN- (Formula presented.) 2b high in the enriched IFN- (Formula presented.) 2b phase (up to 23.22) and low in the BSA-enriched phase (down to 0.00). SDS-PAGE analysis confirmed the purity of both recovered proteins. The stability and structure of IFN- (Formula presented.) 2b and BSA were preserved or even improved (FIL-rich phase) during the purification step, as evaluated by CD spectroscopy and DSC. Binding studies of IFN- (Formula presented.) 2b and BSA with the ABS phase-forming components were assessed by MST, showing the strong interaction between FILs aggregates and both proteins. In view of their biocompatibility, customizable properties, and selectivity, FIL-based ABSs are suggested as an improved purification step that could facilitate the development of biologics.