Oriented immobilization of glucose oxidase on graphene oxide

The oriented immobilization of glucose oxidase (GOD) on a selective support composed of graphene oxide (GO) and concanavalin A (Con A) was prepared in this study. Specially, the amino groups of Con A were covalently attached to the carboxyl groups of pre-activated GO, and then GOD was oriented immobilized on the GO–Con A conjugate via strong biospecific affinity between the sugar residues of GOD and Con A. Compared with free GOD and randomly immobilized GOD (GO–GOD), the high-affinity of Con A and GOD endowed the oriented immobilized GOD (GO–Con A–GOD) with a wider pH stability range, a better thermal stability, a longer-term storage stability and a higher resistance ability toward the denaturing agents. The Michaelis constant (Km) of GO–Con A–GOD was very close to that of free GOD. Hopefully, the GO–Con A–GOD may be further integrated into functional bioelectrodes for biosensor applications.

► GO was used as the immobilization support for GOD.
► GO was functionalized by Con A via diimide-activated amidation.
► GOD was oriented immobilized on a selective support composed of GO and Con A.
► Oriented immobilization of GOD had enhanced pH, thermal and storage stability.
► Oriented immobilized GOD had high affinity for glucose.