One-pot preparation of conductive composite containing boronic acid derivative for non-enzymatic glucose detection

The composite consisting of poly(azure A), gold nanoparticles and 4-mercaptophenylboronic acid (PAA-AuNPs-MPBA) was prepared on the glassy carbon electrode surface by using a one-pot electropolymerization protocol. The generation of poly(azure A) film, the reduction of HAuCl₄ and the binding of MPBA on metallic gold were simultaneously achieved in the cyclic voltammetric scan process, which was verified by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements. MPBA on the composite could capture glucose based on the specific boronic acid-diol binding and form a stable 5-membered cyclic boronate ester, which prevented the penetration and the charge transfer of the ferri-/ferrocyanide couple on the electrode surface. The peak-current change was found to be proportional to the logarithm of the glucose concentration in the range 10nM-10μM with a detection limit of 4nM. The proposed sensor exhibited good immunity from interference of several physiological compounds, reliable reproducibility and satisfying stability and it was successfully used in the determination of glucose in human serum sample.