title: Colorimetric determination of urinary adenosine using aptamer-modified gold nanoparticles.
abstract: This paper describes a colorimetric sensing approach for the determination of adenosine triphosphate (ATP) using aptamer-modified gold nanoparticles (Apt-Au NPs). In the absence of the analytes, the color of the Apt-Au NPs solution changed from wine-red to purple as a result of salt-induced aggregation. Binding of the analytes to the Apt-Au NPs induced folding of the aptamers on the Au NP surfaces into four-stranded tetraplex structures (G-quartet) and/or an increase in charge density. As a result, the Apt-Au NPs solution was wine-red in color in the presence of the analytes under high salt conditions. For mixtures of ATP (20.0-100.0nM), Apt-Au NPs (3.0nM), 10.0% poly(ethylene glycol), 0.2microM TOTO-3, 150.0mM NaCl, 15.0mM KCl, and 16.0mM Tris-HCl (pH 7.4), a linear correlation (R(2)=0.99) existed between the ratio of the extinctions of the Apt-Au NPs at 650 and 520nm (Ex(650/520)) and the concentration of ATP. The limit of detection for ATP was 10.0nM. The practicality of this simple, sensitive, specific, and cost-effective approach was demonstrated through the determination of the concentration of adenosine in urine samples.
authors: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
authors: Shih-Ju
authors: SJ
authors: Chen
authors: Yu-Fen
authors: YF
authors: Huang
authors: Chih-Ching
authors: CC
authors: Huang
authors: Kun-Hong
authors: KH
authors: Lee
authors: Zong-Hong
authors: ZH
authors: Lin
authors: Huan-Tsung
authors: HT
authors: Chang
mesh_terms: D000241:Adenosine / Q000652:urine*; D052158:Aptamers, Peptide / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D016482:Urinalysis / Q000379:methods*
chemical_list: D052158:Aptamers, Peptide; D006046:Gold; D000241:Adenosine