Adsorption and Separation of Trypsin Using Deep Eutectic Solvent‐Functionalized Magnetic Polydopamine

ABSTRACT Five deep eutectic solvent (DES)‐functionalized magnetic polydopamine (MPDA) composites were designed and synthesized via an ultrasound‐assisted method, and subsequently integrated with magnetic solid‐phase adsorption (MSPA) for the efficient adsorption of trypsin. Among them, MPDA@[ChCl][EG], functionalized with a DES composed of choline chloride and ethylene glycol, exhibited the highest adsorption efficiency. The morphology, magnetic responsiveness, and functional group distribution of MPDA@[ChCl][EG] were characterized by transmission electron microscopy, vibrating sample magnetometry, and fourier‐transform infrared spectroscopy. Single‐factor optimization experiments were conducted to investigate the key parameters affecting trypsin adsorption. Under optimal conditions, MPDA@[ChCl][EG] achieved an adsorption capacity of 338.99 mg·g −1 for trypsin, with an equilibrium time of 60 min. The adsorption behavior was well described by the Langmuir isotherm and pseudo‐second‐order kinetic models, indicating monolayer chemisorption. Furthermore, MPDA@[ChCl][EG] was successfully applied to the adsorption and separation of trypsin from a complex biological sample (bovine pancreas crude extract). This strategy of constructing magnetic adsorbents using green DESs and MPDA offers new possibilities for protein adsorption under mild conditions.