An Nd3+-Sensitized Upconversion Fluorescent Sensor for Epirubicin Detection

We describe here an Nd3+-sensitized upconversion fluorescent sensor for epirubicin (EPI) detection in aqueous solutions under 808 nm laser excitation. The upconversion fluorescence of nanoparticles is effectively quenched in the presence of EPI via a fluorescence resonance energy transfer mechanism. The dynamic quenching constant was 2.10 x 10(4) M-1. Normalized fluorescence intensity increased linearly as the EPI concentration was raised from 0.09 mu M to 189.66 mu M and the fluorometric detection limit was 0.05 mu M. The sensing method was simple, fast, and low-cost and was able to be applied to determine the levels of EPI in urine with spike recoveries from 97.5% to 102.6%. Another important feature of the proposed fluorescent sensor is that it holds a promising potential for in vivo imaging and detection due to its distinctive properties such as weak autofluorescence, low heating effect, and high light penetration depth.