Chitosan-induced Au/Ag nanoalloy dispersed in IL and application in fabricating an ultrasensitive glucose biosensor based on luminol–H2O2–Cu2+/IL chemiluminescence system

• Chitosan-induced Au/Ag nanoalloy dispersed in IL was synthesised.
• Glucose biosensor fabricated by covalent immobilization of enzyme and nanoalloy.
• The nanoalloy catalyzes enzymatic reaction and the CL reaction.
• Immobilized IL on biosensor along Cu2+ in assay solution forms [Cu2+]/IL complex.
• [Cu2+]/IL decreases the CL reaction pH and increases enzymatic reaction kinetic.

A novel glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated hydrogen peroxide (H2O2) was constructed by one covalent immobilization of glucose oxidase (GOD) in glutaraldehyde-functionalized glass cell. In following, chitosan-induced Au/Ag nanoparticles dispersed in ion liquid (IL) were synthesised and immobilized on it. Herein, chitosan molecules acted as both the reducing and stabilizing agent for the preparation of NPs and also, as a coupling agent GOD and Au/Ag alloy NPs. In addition to catalyze luminol CL reaction, these NPs offered excellent catalytic activity toward hydrogen peroxide generation in enzymatic reaction between GOD and glucose. The used IL in fabrication of biosensor increased its stability. Also, IL alongside Cu2+ accelerated enzymatic and CL reaction kinetic, and decreased luminol CL reaction optimum pH to 7.5 which would enable sensitive and precision determination of glucose. Under optimum condition, linear response range of glucose was found to be 1.0 × 10−6–7.5 × 10−3 M, and detection limit was 4.0 × 10−7 M. The CL biosensor exhibited good storage stability, i.e., 90% of its initial response was retained after 2 months storage at pH 7.0. The present CL biosensor has been applied satisfactory to analysis of glucose in real serum and urine samples.

Figure optionsDownload as PowerPoint slide