A simple and flexible enzymatic glucose biosensor using chitosan entrapped mesoporous carbon nanocomposite

Abstract A flexible and promising amperometric glucose biosensor was reported using direct immobilization of glucose oxidase (GOx) on chitosan supported mesoporous carbon (MPC-CHT) nanocomposite. The availability of more functional groups particularly amine groups, the CHT was selected as an immobilization matrix as well as cross linker for GOx. The MPC-CHT-GOx composites were characterized well and discussed in details. The MPC-CHT-GOx modified electrode accelerates fast electron transfer on the electrode surface due to the excellent intermolecular interaction between the CHT and GOx molecule. Besides, the MPC-CHT-GOx composite showed well-defined redox behavior with enhanced direct electron transfer (DET) of GOx in PBS, pH 7. Amperometric response of MPC-CHT-GOx modified electrode displayed a good linear response over the glucose concentration ranges from 250 μM to 3 mM with a detection limit (LOD) and sensitivity of 4.1 μM and 56.12 μA mM −1  cm −2 , respectively. The MPC-CHT-GOx modified electrode also displayed good charge transfer coefficient (α) and heterogeneous rate constant (k s ) values are 0.56 and 2.2182 s −1 . Besides, the MPC-CHT-GOx modified electrode exhibited good bio-catalytic activity with the Michaelis-Menten saturation (K m app ) value was about 2.14 mM. The practicability of the sensor was evaluated in biological real samples with satisfactory recoveries.