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

Abstract

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 × 10 −7 to 1.35 × 10 −5 M with a low detection limit of 5.0 × 10 −8 M towards d-glucose.