Determination of ATP by resonance light scattering using a binuclear uranyl complex and aptamer modified gold nanoparticles as optical probes

We describe a resonance light scattering (RLS) method for the direct detection of adenosine triphosphate (ATP) in aqueous solution without the need for separation. The binuclear uranyl complex bis-uranyl-bis-sulfosalophen (BUBSS) was synthesized by the coordination reaction of two uranyl ions with the ditopic tetradentate ligand bis-sulfosalophen. In parallel, gold nanoparticles were modified with anti-ATP aptamer (Apt-AuNPs) to serve as RLS probes. The detection scheme is based on the specific reaction of a BUBSS molecule with two ATP molecules to form a linear supramolecule. This, in turn, binds two Apt-AuNPs molecules, and this is accompanied by the aggregation of the Apt-AuNPs and results in a strong RLS signal. A RLS method was developed on this basis that has a linear response to ATP in the 5 to 500 nM concentration range, with a 4.5 nM detection limit under optimal conditions. The method has been successfully applied to the detection of ATP in spiked real samples and gave recoveries between 96.3 and 102.5 %.