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

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 × 20 μm 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.