title: Simple, fast and selective detection of adenosine triphosphate at physiological pH using unmodified gold nanoparticles as colorimetric probes and metal ions as cross-linkers.
abstract: We report a simple, fast and selective colorimetric assay of adenosine triphosphate (ATP) using unmodified gold nanoparticles (AuNPs) as probes and metal ions as cross-linkers. ATP can be assembled onto the surface of AuNPs through interaction between the electron-rich nitrogen atoms and the electron-deficient surface of AuNPs. Accordingly, Cu2+ ions induce a change in the color and UV/Vis absorbance of AuNPs by coordinating to the triphosphate groups and a ring nitrogen of ATP. A detection limit of  50 nM was achieved, which is comparable to or lower than that achievable by the currently used electrochemical, spectroscopic or chromatographic methods. The theoretical simplicity and high selectivity reported herein demonstrated that AuNPs-based colorimetric assay could be applied in a wide variety of fields by rationally designing the surface chemistry of AuNPs. In addition, our results indicate that ATP-modified AuNPs are less stable in Cu2+, Cd2+ or Zn2+-containing solutions due to the formation of the corresponding dimeric  metal-ATP complexes.
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, Henan, China. ddh@aynu.edu.cn
authors.forename: Dehua
authors.initials: D
authors.lastname: Deng
authors.forename: Ning
authors.initials: N
authors.lastname: Xia
authors.forename: Sujuan
authors.initials: S
authors.lastname: Li
authors.forename: Chunying
authors.initials: C
authors.lastname: Xu
authors.forename: Ting
authors.initials: T
authors.lastname: Sun
authors.forename: Huan
authors.initials: H
authors.lastname: Pang
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D015335:Molecular Probes; D013056:Spectrophotometry, Ultraviolet
chemical_list: D015335:Molecular Probes; D006046:Gold; D000255:Adenosine Triphosphate