A Highly Sensitive Biosensor Based on a Versatile Approach for Immobilization of Glucose Oxidase via "Click" Reaction for Detection of Glucose

A novel immobilized method, "click" reaction, was employed to capture glucose oxidase (GOD). First, azido-terminated carbon nanotubes (CNTs-N-3) were obtained by bifunctional azide molecule (amine-PEG-azide) and alkynyl-modified GOD (alkynyl-GOD) was also synthesized. Subsequently, CNTs-N-3 was reacted with alkynyl-GOD in a copper(I)-catalyzed click reaction. Finally, the mixture was dipped onto the surface of glassy carbon electrode with the help of Nafion to construct a highly sensitive biosensor for the detection of glucose. The results of the both click reaction were monitored by IR spectroscopy, and the electrochemical performance of the modified electrode was studied by cyclic voltammetry and chronoamperometry. Under optimal conditions, the developed sensor exhibited fast response to glucose and the linear ranges were 6.0 x 10(-7) -1.4 x 10(-3) mol/L with a detection limit of 2.0 x 10(-7) mol/L (at 3 sigma). The proposed biosensor exhibited high sensitivity, long-term stability, excellent reproducibility. In addition, the serum samples were analyzed by this biosensor with satisfactory results.