Efficient immobilization of glucose oxidase by in situ photo-cross-linking for glucose biosensing

A glucose biosensor was fabricated based on electrostatic self-assembly in combination with in situ photo-cross-linking of glucose oxidase (GOx) and diazoresin–chitosan (DAR–CS) on Prussian blue deposited multi-walled carbon nanotubes (PB-MWNTs) backbone. It was demonstrated that GOx was initially ionically deposited and subsequently covalently photo-cross-linked onto the PB-MWNTs backbone using photosensitive DAR–CS as the assembly interlayer. The modified electrode exhibited good electrical conductivity and effective electron transfer mediation toward H2O2 reduction due to the employment of PB-MWNTs as the fabrication backbone. The biosensor showed high sensitivity of 77.9 μA mM−1 cm−2 to glucose in the linear concentration range from 1.0×10−5 to 1.1×10−3 M with fast response time of 10 s, detection limit of 3.1×10−6 M, and good anti-interference ability. More importantly, the biosensor exhibited greatly improved biosensing stability in comparison with the non-photo-cross-linked biosensor attributed to the conversion of weak ionic bonds to strong covalent ones for enzyme immobilization by the proposed strategy. The results for glucose determination in real serum samples with the biosensor were found to be in good agreement with those obtained by the conventional clinical procedure.