A sensitive non-enzyme sensing platform for glucose based on boronic acid-diol binding

A sensitive non-enzyme sensing platform for D-glucose based on the specific boronic acid-diol binding was established. Prussian blue (PB) which was co-deposited with gold nanoparticles (AuNPs) to form Au-PB nanocomposite on gold electrode surface was employed to be the electrochemical indicator. To further improve the sensitivity of the sensor, a second AuNPs layer was assembled on the Au-PB nanocomposite via electroless metallization induced by catechol group of polydopamine. The in situ generated AuNPs afforded multiple binding sites for 4-mercaptophenylboronic acid (MPBA) self-assembly on the electrode surface via Au-S interaction. MPBA reacted with the 1,2-diol of D-glucose to form a stable 5-membered cyclic boronate ester and the binding event was monitored by the decreased current signal of PB moiety. Due to the high affinity of MPBA for D-glucose and high stability of the resulting sensing platform as well as the existence of AuNPs, the fabricated sensor exhibited high selectivity, good sensitivity, and wide linear range from 1.0 x 10(-7) to 1.35 x 10(-5) M with a low detection limit of 5.0 x 10(-8) M towards D-glucose. (C) 2011 Elsevier B.V. All rights reserved.