Gold nanoparticle-based colorimetric detection of ATP via a label-free aptamer.

Adenosine triphosphate (ATP) is an important detection content in many biological reaction detection. At present, the detection methods of ATP mainly focused on electrophoresis, optical analysis, chromatography, and bioluminescence. However, these methods are not widely applied due to the high cost, complicated operation, time-consuming and low sensitivity. Here we developed a simple, fast and sensitive ATP biosensor with the specific aptamer as the recognition element and the unmodified gold nanoparticle (AuNPs) as the colorimetric probe. In the high salt environment, the aggregation of AuNPs causes the color change from red to blue. However, in the presence of aptamer, the free aptamers protect the AuNPs from aggregation and keeps the color of the solution red. Conversely, in the presence of ATP, aptamers are consumed to form aptamer-ATP complex, the AuNPs lose their protection and aggregate with the visual color change from red to blue. Our results show that ATP with a linear range of 5-320 μM can be detected. In conclusion, nanoparticles-based colorimetric method is feasible for ATP detection and has great potential in clinical screening.