Aqueous two-phase systems comprising ionic liquids for the extraction of recombinant proteins

Abstract

The progress made on the use of new biopharmaceuticals has a high influence on the global health, and since the approval of humulin (recombinant insulin) by FDA, new protein-based pharmaceuticals have been introduced in the market such as the interferon alfa 2b (IFNα2b), which has been used in in the treatment of oncological diseases for more than 30 years. Nowadays, the (bio)pharmaceutical industry is committed to improve the quality of their products while endeavoring a reduction of its production costs. Currently, the downstream processing of biopharmaceuticals is dominated by chromatography and, despite being highly effective, is responsible for their current high-cost [1]. Accordingly, there is a crucial need to develop effective alternative purification platforms. In this way, aqueous two-phase systems (ATPS) emerge. Due to their high-water content, ATPS may be considered a biocompatible technique for the purification of (bio)molecules. Additionally, the use of ionic liquids (ILs) in low concentrations as adjuvants in ATPS affords an enhanced performance in what concerns to (bio)molecules selectivity. In this work it is shown the use of polymer-polymer ATPS comprising ILs as adjuvants to purify recombinant proteins. Several variables were studied in the extraction of the target proteins, namely pH, polymer molecular weight, and the effect of different families of ILs and their concentration. Overall, imidazolium-based ILs seem responsible for an improved ATPS performance towards a higher purity, and is additionally shown that electrostatic interactions between the negatively charged protein and ILs cations may account for this behavior.