Detection of biological mercaptan by DNA functionalized room temperature phosphorescent quantum dot nanocomposites.

In this study, green low-toxicity Mn-doped Zns (Mn-Zns) room-temperature phosphorescent (RTP) quantum dots (QDs) (PQDs) nanocomposites (DNA-PQDs) were prepared under the optimal conditions by using single-stranded DNA (PS-C-ssDNA) rich of cytosine C and Thioguanine G (PS) as the template. DNA-PQDs interact with Ag+ to form AgN bonds and further produce C-Ag+–C conjugates. As a result, DNA-PQDs cluster together and induce the phosphorescent exciton energy transfer (PEET), resulting in quenching of room-temperature phosphorescent of DNA-PQDs. Nevertheless, Ag+ tends to form AgS bonds with biological mercaptan when it is added in, so that Ag+ falls from C-Ag+–C. DNA-PQDs changed from aggregation to looseness and RTP is recovered accordingly. On this basis, RTP detection of biological mercaptan is realized. Since this sensor system has RTP properties based on DNA-PQDs, it is very applicable to detection of mercaptan compounds in biological fluids.