Novel Biocompatible and Self‐buffering Ionic Liquids for Biopharmaceutical Applications

Antibodies obtained from egg yolk of immunized hens, immunoglobulin Y (IgY), are an alternative to the most focused mammal antibodies, because they can be obtained in higher titers by less invasive approaches. However, the production cost of high‐quality IgY for large‐scale applications remains higher than that of other drug therapies due to the lack of efficient purification methods. The search for new purification platforms is thus vital. The solution could be liquid–liquid extraction by using aqueous biphasic systems (ABS). Herein, we report the extraction and attempted purification of IgY from chicken egg yolk by using a new ABS composed of polymers and Good’s buffer ionic liquids (GB‐ILs). New self‐buffering and biocompatible ILs based on the cholinium cation and anions derived from Good’s buffers were synthesized and the self‐buffering characteristics and toxicity were characterized. Moreover, when these GB‐ILs are combined with PPG 400 (poly(propylene) glycol with a molecular weight of 400 g mol^‐1) to form ABS, extraction efficiencies, of the water‐soluble fraction of proteins, ranging between 79 and 94 % were achieved in a single step. Based on computational investigations, we also demonstrate that the preferential partitioning of IgY for the GB‐IL‐rich phase is dominated by hydrogen‐bonding and van der Waals interactions.