Biocompatible magnetic cellulose-chitosan hybrid gel microspheres reconstituted from ionic liquids for enzyme immobilization

Magnetic Fe3O4-cellulose-chitosan hybrid gel microspheres were prepared by sol-gel transition technology using ionic liquids as solvent for cellulose and chitosan dissolution and regeneration. The synthesized microspheres were characterized by XRD, FTIR, SEM, and vibrating sample magnetometer (VSM). The XRD and FTIR results showed that chitosan and cellulose had been successfully coated onto the surface of Fe3O4 after the preparation. SEM presented that the synthesized microspheres were regular sphere with a mean diameter of about 10 mm. Furthermore, it was found that glucose oxidase (GOx) could be successfully immobilized on the hybrid gel microspheres via glutaraldehyde technique. The immobilized enzyme presented higher thermostability, wider range of pH optima and improved storage stability in comparison with free GOx. The glucose conversion could reach 91.5% within 4 h and retained 84.2% of the initial activity after 15 cycles of use. These results demonstrate their potential applications in the field of biocatalysis.