Cage-like PbS nanostructure for the construction of novel glucose electrochemical biosensor

A novel glucose electrochemical biosensor was constructed based on the immobilization of glucose oxidase (GOx) in cage-like PbS nanostructure. The fabricated biosensor was characterized by scanning electron microscopy, UV-vis spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry, respectively. The direct electrochemistry of GOx at cage-like PbS nanostructure modified glassy carbon electrode was for the first time studied. The cage-like PbS nanostructure has larger surface area and provides a favorable microenvironment for facilitating the direct electron transfer between enzyme and electrode surface. The immobilized enzymes on PbS cage-like nanostructure retains its native structure and bioactivity and shows a surface controlled, reversible two-proton and two-electron transfer reaction with a apparent electron transfer rate constant of 2.85 s−1. The biosensor shows wide linear range for glucose from 5.0 × 10−5 M to 1.45 × 10−3 M with high sensitivity of 11.02 mA M−1 cm−2. The detection limit was calculated to be 1.0 × 10−5 M at signal-to-noise of 3. Moreover, the proposed glucose biosensor displays excellent selectivity, good reproducibility, and acceptable operational stability and can be successfully applied in the detection of glucose in serum sample. The cage-like PbS nanostructure provides a promising approach for immobilizing proteins and fabricating excellent biosensors.