Near-infrared light excited UCNP-DNAzyme nanosensor for selective detection of Pb2+ and in vivo imaging.

Due to similar charges, atomic radii, and chemical properties of most metal ions, the selective sensing of these metal ions and imaging in vivo is still a challenge. A DNAzyme assemblied and near-infrared (NIR) light excited nanosensor was developed to detect and image Pb2+. In this nanosensor, NaYF4:Yb, Er upconversion nanoparticles (UCNPs) introduced as NIR-to-Vis transducer were the donor of luminescence resonance energy transfer (LRET), and DNAzyme-functionalized black hole quencher 1 (BHQ1) acted as energy transfer acceptor. This proposed nanosensor was applied to detecting Pb2+ in solution with high sensitivity and selectivity. Furthermore, we have successfully demonstrated the imaging ability of this nanosensor towords Pb2+ in living cells and early-stage zebrafish with negligible autofluorescence and good photostability. The UCNP-DNAzyme nanosensor would enrich the method of imaging Pb2+ in vivo, and might serve as a potential tool for understanding the metabolic pathways of Pb2+ and the mechanism of lead poisoning in biological system.