Composite quantum dots detect Cd(ii) in living cells in a fluorescence “turning on” mode

Abstract

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.