A super highly sensitive glucose biosensor based on Au nanoparticles–AgCl@polyaniline hybrid material

Gold nanoparticles (AuNPs) with an average diameter of 5 nm were assembled on the surface of silver chloride@polyaniline (PANI) core-shell nanocomposites (AgCl@PANI). Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) suggested that AuNPs were incorporated on AgCl@PANI through coordination bonds instead of electrostatic interaction. The resulting AuNPs–AgCl@PANI hybrid material exhibited good electroactivity at a neutral pH environment. An amperometric glucose biosensor was developed by adsorption of glucose oxidase (GOx) on an AuNPs–AgCl@PANI modified glassy carbon (GC) electrode. AuNPs–AgCl@PANI could provide a biocompatible surface for high enzyme loading. Due to size effect, the AuNPs in the hybrid material could act as a good catalyst for both oxidation and reduction of H2O2. As the measurement of glucose was based on the electrochemical detection of H2O2 generated by enzyme-catalyzed-oxidation of glucose, the biosensor exhibited a super highly sensitive response to the analyte with a detection limit of 4 pM. Moreover, the biosensor showed good reproducibility and operation stability. The effects of some factors, such as temperature and pH value, were also studied.