Three-Dimensional Porous Ti₃C₂T_x MXene-Graphene Hybrid Films for Glucose Biosensing

Incorporating two-dimensional (2D) graphene sheets into a 3D graphene structure provides porous structures to bind enzyme but with low enzyme affinity and unstable structure because of removal of the surficial functional group and the flexibility of graphene sheets. To address this issue, we herein constructed a 3D porous Ti₃C₂T_x MXene-graphene (MG) hybrid film through a facile mixing-drying process. Ti₃C₂T_x MXene nanosheets (MNS) with hydrophilic groups on the rigid flakes endowed the MG hybrid film with open porous structure and a highly hydrophilic miroenvironment. By simply controlling the content of Ti₃C₂T_x MNS and graphene sheets, the sizes of the internal pores were accordingly tunable. The 3D porous hybrid film, fabricated from Ti₃C₂T_x MNS and graphene sheets (weight ratios of 1:2 abd 1:3), supplied more open structure to facilitate the glucose oxidase (GOx) entering the internal pores, which probably enhanced the stable immobilization and retaining of the GOx in the film. As a result, the as-proposed biosensor exhibited prominent electrochemical catalytic capability toward glucose biosensing, which was finally applied for glucose assay in sera. The preparation of the size-controlled 3D porous hybrid film provided a method for effectively binding enzymes/protein further to develop elegant biosensors.