Hydrophobic Ionic Liquid Gel Microspheres as Bi-Component Carriers with a Liquid Phase to Immobilize Enzymes for Enhanced Performance

This study focuses on incorporating liquid molecules, different from the bulk solution, into the immobilized enzyme carrier to regulate the distribution effect and diffusion-limiting impact of the carrier's microenvironment for substrates, which generally is difficult to achieve due to the instability of the materials with liquid inclusions. A freestanding liquid-holding particle carrier, with bi-component hydrophobic ionic liquid gel microspheres with poly (glycidyl methacrylate) as the network and 1-butyl-3-methylimidazolium hexafluorophosphate as the dispersing medium, is proposed, which is stable in air aqueous solution, and can extract proteins and organic small molecules into its interior due to the mobility of its dispersing medium. Horseradish peroxidase is covalently immobilized into the microspheres, forming a liquid compartment enzyme microreactor. The microreactor exhibits superior stability, enzymatic activity, and catalytic performance for Basic Orange II degradation compared to free enzyme and liquid-free immobilized enzymes. This is attributed to the biocompatibility of the ionic liquid, its role in substrate enrichment in its interior, and its rapid mass transfer capability. This contribution shows the effectiveness of regulating the carrier's microenvironment with liquid molecules, offering fresh perspectives and strategies for enzyme technology.