Deep eutectic solvent and styrene copolymer-shelled magnetic microspheres for the capture of Ovomucoid in foods and their interactions

Fe₃O₄ is a cost-effective and strong magnetic core, meanwhile polymerizable deep eutectic solvents (PDESs) are considered to have excellent performance and biocompatibility in separation and material fields. Therefore, the aim was to prepare magnetic microspheres (P(DES-co-St)@Fe₃O₄) with Fe₃O₄ as the core and PDESs (choline chloride/acrylic acid, 1:2; choline chloride/itaconic acid, 1:1)-styrene (St) copolymer as the shell for binding of target protein. The resulting microspheres exhibited ideal magnetic responsiveness (14.14 emu·g^-1), stability, dispersion and uniformity (average diameter of 1.04 μm). The acidic PDESs endowed the surface structure of magnetic microspheres with numerous carboxyl groups (3.71 mmol·g^-1), providing multiple active sites to capture allergenic proteins (ovomucoid, ovotransferrin, ovalbumin) from foods. Under current conditions, the binding capacity of ovomucoid was determined to be 155.3 mg·mL^-1. Kinetic and thermodynamic studies, along with fluorescence spectroscopy and molecular simulations, indicated that the magnetic microspheres bind with ovomucoid through a combination of monolayer multiple interactions with selectivity.