title: A highly sensitive aptamer-nanogold catalytic resonance scattering spectral assay for melamine.
abstract: The aptamer (ssDNA) was used to label nanogold (NG) particle to fabricate an aptamer-nanogold (NGssDNA) probe for melamine. The probe was stabile in pH 6.6 Na(2)HPO(4)-NaH(2)PO(4) buffer solutions and in the presence of high concentration of electrolyte. Upon addition of melamine, it interacted with the probe to form big NGssDNA-melamine aggregations that led to the resonance Rayleigh scattering (RRS) intensity at 566 nm increased greatly. The increased RRS intensity (ΔI) is linear to melamine concentration in the range of 1.89-81.98 μg/L, with a detection limit of 0.98 μg/L melamine. The unreacted probe in the aptamer reaction solution exhibited strong catalytic effect on the slow Cu(2)O particle reaction between glucose and Fehling reagent, but the catalytic activity of NG aggregations is very weak. When melamine concentration increased, the unreacted probe decreased, the RRS peak intensity at 614 nm decreased. The decreased RS intensity is linear to melamine concentration in the range of 0.63-47.30 ng/L melamine, with a detection limit of 0.38 ng/L. The aptamer-modified nanogold catalytic RRS assay was applied to determination of melamine in milk, with high sensitivity and selectivity, simplicity and rapidity.
authors.affiliation: Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin 541004, China.
authors.forename: Aihui
authors.initials: A
authors.lastname: Liang
authors.forename: Lianping
authors.initials: L
authors.lastname: Zhou
authors.forename: Huimin
authors.initials: H
authors.lastname: Qin
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huixiang
authors.initials: H
authors.lastname: Ouyang
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D014227:Triazines / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D014227:Triazines; D006046:Gold; C011907:melamine