Immobilization of glucose oxidase onto cobalt based on silica core/shell nanoparticles as carrier

Co–B/SiO2/NH2 magnetic nanoparticles (NPs) were prepared from a silica shell-coated Co–B core using the Stöber method and amine-modification on the surface. Glucose oxidase (GOD) was covalently immobilized on the surface of Co–B/SiO2/NH2 NPs using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) as an activating agent. The magnetic NPs characteristics, such as the synthesis of Co–B/SiO2/NH2 NPs, effect of pH, temperature, and concentration of buffer for enzyme immobilization, were investigated. The optimal reaction conditions for immobilization were determined to be 0.1 M of phosphate buffer solution, pH 7.0, and 5 °C. In the case of immobilized GOD without d-glucose and with 0.1 M of d-glucose for blocking, 22.98 U/g and 24.83 U/g of their original activity were retained after 7 reuses, respectively.

► The cobalt based on silica core/shell nanoparticles (NPs) was developed as carrier. ► Glucose oxidase (GOD) was immobilized onto the magnetic NPs. ► The result showed higher activity with d-glucose for blocking than without d-glucose. ► In the case of immobilized GOD with d-glucose, its activity was retained after 7 reuses.