D-Proline capped gold nanoclusters for turn-on detection of serum Raltitrexed

With;-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared（;-Pro@AuNCs） within 10 min at 100℃. In the present of gold nanoparticles, the fluorescence of;Pro@AuNCs was remarkably quenched. Interestingly, based on the electrostatic interaction between anticancer drug Raltitrexed and gold nanoparticles induced fluorescence "turn-on" principle, a high selective assay for detection of Raltitrexed was established with the probe associating the fluorescence emission at 435 nm. The fluorescence intensity of;-Pro@AuNCs linearly correlated with the concentration of Raltitrexed in the range from 5.0 mmol/L to 40.0 mmol/L（R;= 0.999） and the limit of detection was 1.9 mmol/L. Further, after Raltitrexed was abdominal injected in rats, a metabolic approach was constructed with the prepared fluorescent probe. It showed great potential of AuNCs-based sensing probes for application in analysis of serum anticancer drugs.