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.
Highlights
Adenosine triphosphate (ATP) is known to be the universal energy currency in all biological systems and to contribute to cell metabolism, biochemical reactions and active transport
Due to the unique size-dependent optical properties of gold nanoparticles (AuNPs), AuNP-based colorimetric assays have been widely applied in a variety of research fields, such as the screening of kinase activity and the measurement of the concentrations of nucleic acid, proteins, metal ions and other small molecules [21,22,23,24,25,26,27,28,29,30]
ATP, adenosine diphosphate (ADP), adenosine monophosphate (AMP), guanosine triphosphate (GTP), cytidine triphosphate (CTP), NTP mixture and boric acid were purchased from Sangon Biotech
Summary
Adenosine triphosphate (ATP) is known to be the universal energy currency in all biological systems and to contribute to cell metabolism, biochemical reactions and active transport. Due to the unique size-dependent optical properties of gold nanoparticles (AuNPs), AuNP-based colorimetric assays have been widely applied in a variety of research fields, such as the screening of kinase activity and the measurement of the concentrations of nucleic acid, proteins, metal ions and other small molecules [21,22,23,24,25,26,27,28,29,30] Such methods are very promising in that they involve very simple sample handling procedures and minimum instrumental investments and can be conducted in the field with portable devices. The present method is selective to ATP and is much faster and simpler than the existing methods, without the need for expensive and complicated instruments
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