Glutamate Biosensor Using a DNA-Cu(II)/polyamine Membrane as a Novel Electrocataytic Layer for Cathodic Determination of Hydrogen Peroxide

Abstract

Novel glutamate biosensor was fabricated by coupling of a glutamate oxidase (GlOx) to a copper ion embedded polyion complex membrane composed of double-stranded DNA and polyallylamine (PAA), which prepared on a surface of the glassy carbon (GC) electrode. A hydrogen peroxide (H2O2) produced during the GlOx reaction was cathodically detected, based on an electrocatalytic activity of a DNA-Cu(II) complex for a reduction of H2O2. The cathodic current responses to L-glutamate obtained at −0.2 V (vs. Ag/AgCl) and at pH 6.0 linearly increased up to 100 µM with a detection limit of 1 µM (S/N=3). The sensitivity (slope of the linear region) was 0.80 nA/µM, and the response time was less than 20∼30 s. The sensor retained its response characteristics for at least five days by the storage in dry state at 4°C.