Characterization of an ultrasensitive biosensor based on a nano-Au/DNA/nano-Au/poly(SFR) composite and its application in the simultaneous determination of dopamine, uric acid, guanine, and adenine

• Published in: Sensors and actuators. B, Chemical Chemical, 2013-03, Vol.178, p.10-18
• Main Authors: Niu, Ling Mei, Lian, Kao Qi, Shi, Hong Mei, Wu, Yi Bing, Kang, Wei Jun, Bi, Si Yuan
• Format: Article
• Language: English
• Subjects: Adenine; atomic force microscopy; biosensors; blood serum; carbon; detection limit; dielectric spectroscopy; Dopamine; electrodes; gold; Gold nanoparticles; Guanine; humans; microstructure; nanogold; oxidation; scanning electron microscopy; surface area; Uric acid; urine
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2012.12.015

An ultrasensitive method for the simultaneous determination of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) was developed using differential pulse voltammetry with a three-dimensionally distributed Au nanoparticle (GNP)-modified glassy carbon electrode (GCE). The nano-Au/DNA/nano-Au/poly(SFR)/GCE microstructure was characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and atomic force microscopy, showing an anchored three-dimensional distribution of GNPs on the modified electrode. The electrode exhibited ultrasensitive responses to DA, UA, G, and A due to poly(SFR) electrocatalytic activities and the large surface area of the GNPs. All four analytes showed well-defined catalytic oxidation peaks at the modified electrode. DA, UA, G, and A yielded linear ranges from 8.0×10−9M to 1.1×10−6M, 9.0×10−8M to 1.2×10−5M, 9.0×10−9M to 5.0×10−6M, and 6.0×10−8M to 8.0×10−7M, respectively, and detection limits for the analytes were 2.0×10−10M, 8.0×10−9M, 5.0×10−10M, and 4.0×10−9M, respectively. The feasibility of the proposed assay for use in human serum and urine was investigated and satisfying results were obtained.