Study of the interactivity between mercury and cellular system labeled with carboxymethyl chitosan-coated quantum dots and its application in a real-time in-situ detection of mercury.

In this study, canine kidney cells (MDCK) are fluorescently labeled by carboxymethyl chitosan-coated CdTe quantum dots to obtain a stable fluorescence. Fluorescently labeled MDCK cells are incubated with Hg(2+) and passed flow cytometer to measure the mean fluorescence intensity, which shows [Hg(2+)] has a prominent quenching ability on the cells' fluorescence. The dose-dependent relation can be described by Stern-Volmer equation at the concentration range of 5-70 μg/L [Hg(2+)]. This method can be employed to determine the concentration of Hg(2+) in living cells by measuring the changes in fluorescence of the cellular system. The results show a relative standard deviation of 7.16% (n=11) and a recovery rate ranging from 92% to 103%, indicating a promising prospect of application on real-time in-situ analysis of [Hg(2+)] and its cytotoxic effects.