Amperometric Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase-labeled Nano-Au Colloids Immobilized on Poly(2,6-pyridinedicarboxylic acid) Layer by Cysteamine

Abstract

A sensitive hydrogen peroxidase (H₂O₂) amperometric sensor based on horseradish peroxidase (HRP)-labeled nano-Au colloids has been proposed. Nano-Au colloids were immobilized by the thiol group of cysteamine, which was associated with the carboxyl groups of poly(2,6-pyridinedicarboxylic acid) (PPDA). With the aid of the hydroquinone, the sensor displayed excellent electrocatalytical response to the reduction of H₂O₂. Compared with the non-Au-colloid modified electrode, i.e., PPDA/HRP, the Au-colloid modified electrode exhibited better performance characteristics, including stability, reproducibility, sensitivity and accuracy. The biosensor shows a linear response to H₂O₂ in the range of 3.0 × 10^-7 - 2 × 10^-3 M. The detection limit was 1.0 × 10^-7 M.