High-Sensitive Glucose Biosensor Based on Ionic Liquid Doped Polyaniline/Prussian Blue Composite Film

Abstract

The Prussian blue/ionic liquid-polyaniline/multiwall carbon nanotubes (PB/IL-PANI/MWNTs) composite film was fabricated by using cyclic voltammetry. The ion liquid acting as a lubricating agent, could enhance the electron delocalization degree and reduce the structural defects of the polyaniline. The surface morphology of the composite film revealed that the PB nanoparticles have smaller size than that in pure PB film. Due to the introduction of ion liquid, the PB/IL-PANI/MWNTs composite film showed wonderful synergistic effect which can remarkably enhance sensitivity, expand linear range and broaden acidic adaptability for hydrogen peroxide detection. The composite film demonstrated good stability in neutral solution contrast to pure PB film, with a linear range from 2.5 µmol/L to 0.5 mmol/L and a high sensitivity of 736.8 µA·(mmol/L)−1·cm−2 for H2O2 detection. Based on the composite film, an amperometric glucose biosensor was then fabricated by immobilizing glucose oxidase. Under the optimal conditions, the biosensor also exhibits excellent response to glucose with the linear range from 12.5 µmol/L to 1.75 mmol/L and a high sensitivity of 94.79 µA·(mmol/L)−1·cm−2 for H2O2. The detection limit was estimated 1.1 µmol/L. The resulting biosensor was applied to detect the blood sugar in human serum samples without any pretreatment, and the results were comparatively in agreement with the clinical assay.