A label-free fluorescent probe for the detection of adenosine 5'‑triphosphate via inhibiting the aggregation-induced emission enhancement of glutathione modified silver nanoclusters triggered by zinc ion.

It is important to establish sensitive and simple analysis methods for adenosine 5'‑triphosphate (ATP). A label-free fluorescent probe for the determination of ATP was constructed based on glutathione modified silver nanoclusters (AgNCs/GSH). AgNCs/GSH showed aggregation-induced emission enhancement (AIEE) property in the organic solvent. The effects of metal ions on the fluorescence of AgNCs/GSH were also studied. Only zinc ion enhanced the fluorescence of AgNCs/GSH obviously. This was because Zn coordinated with AgNCs/GSH to cause the aggregation of AgNCs/GSH, which was sufficiently proved by TEM. With the addition of ATP, Zn bound with ATP through ZnOP bond and the binding between Zn and AgNCs/GSH was inhibited. Hence the fluorescence of AgNCs/GSH was decreased with increasing the ATP concentration. The fluorescence response was linear in the ATP concentration range of 1-110 μM, and the detection limit was 0.8 μM. Then this method was successfully applied for determining ATP in the samples of human urine and rat serum, the recoveries were in the range of 97.6%-103%.