Composite quantum dots detect Cd(II) in living cells in a fluorescence turning on mode

A fluorescent 'turn-on' sensor based on triethylene-glycol triazole-linked silica nanospheres embedded with CdSe quantum dots (CdSe@SiO2-TGT) via click chemistry has been reported. The composite CdSe@SiO2-TGT sensor showed, as designed, excellent selectivity for Cd2+. To address the problems caused by the most reported signal off mode, sulfite anions were introduced into the CdSe@SiO2-TGT system with a result of fluorescence quenching, and in this case, higher sensitivity of Cd2+ ion recognition was achieved through the specific fluorescence turning on mode. Most significantly, the as-prepared composite quantum dot (CdSe@SiO2-TGT) based fluorescent sensor was successfully imaged and worked in living cells for detecting Cd2+ ions.