Rhodamine-based fluorescent sensor for mercury in buffer solution and living cells

摘要

A novel fluorescent sensor based on thiooxorhodamine B has been prepared to detect Hg~(2+) in aqueous buffer solution. It demonstrates high selectivity for sensing Hg~(2+) with about 383-fold enhancement in fluorescence emission intensity and micromolar sensitivity (K_d = 7.5 x 10~(-6) mol L~(-1)) in comparison with alkali and alkaline earth metal ions (K~+, Na~+, Mg~(2+), Ca~(2+)) and other transition metal ions (Mn~(2+), Ni2~(2+), Co~(2+), Cu~(2+), Zn~(2+), Cd~(2+), Ag~+, Pb~(2+), Cr~(3+), Fe~(3+)). Meanwhile the distinct color changes and rapid switch-on fluorescence also provide 'naked eyes' detection for Hg~(2+) over a broad pH range. Moreover, such sensor is cell-permeable and can visualize the changes of intracellular mercury ions in living cells using fluorescence microscopy.