Optimization and miniaturization of aqueous two phase systems for the purification of recombinant human immunodeficiency virus-like particles from a CHO cell supernatant

Virus-like particles (VLPs) are promising candidates for a new generation of biopharmaceuticals, with a high impact in gene therapy, vaccination and also in the construction of delivery vehicles. Despite the growing interest in these particles, their production is currently limited by the low capacities and throughputs of classical downstream processing technologies. Aqueous two-phase extraction (ATPE) is a promising bioprocessing technique allowing clarification, concentration and purification to be accomplished in a single step. ATPE also combines a high biocompatibility with a simple and reliable scale-up and can also be performed in a continuous mode of operation. In this work, ATPE conditions for the purification of a Human Immunodeficiency Virus (HIV) VLP were screened and optimized in mL scale batch conditions. Polyethylene glycol (PEG)-salt (potassium phosphate, ammonium sulfate and trisodium citrate) and polymer-polymer (PEG-dextran) systems were investigated, among which the PEG-ammonium sulfate system demonstrated the higher partition coefficient (K= 4.4). This parameter was then compared with the obtained in a continuous microfluidic setting, performed by flowing both immiscible phases through a 100 width x 20 mu m wide microchannel. The batch optimization results showed good agreement with the continuous miniaturized extraction, both in terms of K (K = 3.9 in microfluidic scale) and protein purity. These novel findings show that PEG-ammonium sulfate ATPE is a promising system for primary HIV-VLP recovery and demonstrate the potential of a miniaturized ATPE for massive parallelization (scale-out) at the preparative scale or integrated in analytical miniaturized systems. (C) 2015 Elsevier B.V. All rights reserved.