High-throughput screening of aqueous biphasic systems with ionic liquids as additives for extraction and purification of enveloped virus-like particles

Abstract

Due to their unique properties, virus-like particles (VLPs) have been portrayed as a promising high-value biopharmaceutical in VLP-based vaccination and cancer therapy. Nevertheless, due to limited physical and economical capabilities of the current downstream processing of VLPs, their production is still difficult and seen as a major problem that needs to be tackled. In this work, high-throughput screening on a liquid handling station (LHS) has been implemented for efficient selection of adequate polymer-salt aqueous biphasic systems (ABS) for extraction and purification of enveloped Hepatitis C virus pseudoparticles (HCVpp). The effect of polyethylene glycol (PEG) molecular weight and salt type (citrate, sulfate, and phosphate) was first evaluated. Furthermore, to optimize extraction parameters, the effect of pH and tie-line lengths (TLL) was also addressed. For the most promising ABS and extraction conditions, the addition of ten ionic liquids (ILs) as adjuvants was investigated. Insights on the chemical features of ILs that impact HCV-VLPs partitioning are highlighted. Finally, the potential of studied ABS containing ILs as adjuvants in the extraction and purification of VLPs from cell culture supernatants was addressed. The 100% extraction efficiency of VLPs in the PEG-rich phase was achieved, and VLP purity was increased compared to the system without IL. In conclusion, these promising results show that ILs can be very effective in modulating the phase properties of polymer-salt ABS, achieving high HCV-VLP purification.