Development of Ag nanoparticle-carbon quantum dot nanocomplex as fluorescence sensor for determination of gemcitabine.

Gemcitabine hydrochloride is an established chemotherapeutic agent in several solid tumors. In spite of outstanding therapeutic efficacy, there are some serious fetal side effects with gemcitabine in higher concentrations which necessitate developing a sensitive sensor for its quantification. Herein, a fluorescent metal-nanoparticles conjugated carbon quantum dot (MN-CQD) was prepared by a mixture of citric acid/ammonia sulfate and different metals using hydrothermal method. Based on the primary experiments, the efficiency of Ag nanoparticle-CQDs for gemcitabine determination was found to be much better than others. The AgNp-CQDs fluorescence was quenched by gemcitabine anticancer drug via photo-induced charge transfer which renders the system into fluorescence "OFF" status. Under the experimental conditions, the linear range of detection was 0.003-0.1 μM in an aqueous solution with a correlation coefficient of 0.96 and a limit of detection equal to 0.002 µM. The relative standard deviation (RSD) for gemcitabine determination was 3.4% (n = 3). Finally, after optimizing the conditions, the concentration of analyte was determined in real samples including human plasma and urine. These results confirm that the as prepared fluorescence based nanosensor can be used for sensitive quantification of gemcitabine in real samples.