Resonance scattering spectrum detection of trace using nanogold probe as catalyst of Cu(II)-glucose reaction

Abstract

exhibited catalytic effect on the cracking reaction of double-stranded DNA (dsDNA) to form a short single-stranded DNA (ssDNA) that protected the nanogold (NG) to produce stable NGssDNA conjugate. The un-protected NG was aggregated to form NG aggregates (NGA) that appeared a resonance scattering (RS) peak at 542 nm. Unlike NGA, the NGssDNA exhibited a strong catalytic activity on the Cu2O particle reaction of Fehling reagent-glucose that can be monitored by RS technique at 608 nm. When the concentration increased, the NGssDNA increased, and the RS intensity at 608 nm increased. The increased RS intensity ΔI 608 nm was linear to the concentration in the range of 15–200 pmol L−1, with a regression equation of ΔI 608 nm = 1.24 C + 4.6, and a detection limit of 5 pmol L−1. This new RS assay was applied to assay in water sample, with satisfactory results.