Ultrasensitive Fluorescence Determination of 6-Thioguanine in Biological Samples Based on the Silver Nanoparticle-Mediated Release of Acridine Orange Probe.

This article reports a simple, convenient, and very sensitive method for the determination of 6-thio guanine (6-TG). The basic phenomenon in the proposed method is fluorescence resonance energy transfer, where acridine orange (AO) act as a donor and citrate-stabilized silver nanoparticles (AgNPs) as an acceptor. A noncovalent bond between the surfaces of AgNPs and AO was found, and the effect of fluorescence quenching was observed. The fluorescence spectra of AO recovered after further addition of 6-TG are responsible for the aggregation of AgNPs. Under ideal conditions, the linear relationship of 6-TG in the concentration range of 0.005 to 0.04 μM was displayed, and the limit of detection of 6-TG was obtained as 5.3 nM. Under ideal conditions, the linear relationship of 6-TG was displayed in the concentration range of 0.005 to 0.04 μM, and the limit of detection of 6-TG was obtained as 5.3 nM. The proposed method offers a rapid analysis to determine 6-TG in human serum, blood, and urine samples. [ABSTRACT FROM AUTHOR]