Biocompatible mesoporous polymeric ionic liquid with high adsorption capacity for selective isolation of ovalbumin

Ionic liquids are becoming widely applied in the extraction/separation of biological molecules. In this study, the solidification of ionic liquid 1-hydroxyethyl-3-vinylimidazole chloride ([HVIM]Cl) was achieved via one-pot free radical copolymerisation with divinylbenzene (DVB) as a cross-linking reagent, giving a mesoporous hydrophilic polymeric ionic liquid (PIL). Mesoporous PIL possesses a large surface area of 328.32 m2·g−1 and a high pore volume of 0.45 cm3·g−1. Owing to hydrophilic interactions and π–π stacking interactions, the PIL adsorbs ovalbumin (Ova) selectively with a theoretical maximum adsorption capacity of 2468.0 mg·g−1, and this Ova adsorption fit the Langmuir model well. The captured Ova was efficiently recovered using sodium dodecyl sulphate (0.4%, m·v−1) with an elution efficiency of 94.7%. Circular dichroism spectra indicated that the adsorption-elution process caused no conformational changes in Ova, indicating that the prepared PIL is highly biocompatible. The practicability of this mesoporous PIL was well demonstrated by the selective adsorption of Ova from protein mixtures and the efficient isolation of Ova from chicken egg white.