Near-Infrared Two-Photon Fluorescent Chemodosimeter Based on Rhodamine-BODIPY for Mercury Ion Fluorescence Imaging in Living Cells

A novel near-infrared upconversion chemodosimeter for Hg2+ ion (NRhB-BODIPY) was designed and synthesized. In the NIR chemodosimeter, Fisher aldehyde is introduced to the structure of rhodamine dyes in order to extend the wavelength of absorption and emission. The maximal emission bands of NRhB-BODIPY concentrated at 735 nm after adding 5 equivalents Hg2+. The probe can be applied to the quantification detect of Hg2+ with the detection limit of 1.41×10−8 M. Moreover, the response behavior of NRhB-BODIPY towards different pH values exhibited good linear correlation, which means it can also be served as pH probe. NRhB-BODIPY can be used as two-photon fluorescence probe to detect the Hg2+. The NRhB-BODIPY/Hg2+ solution exhibit strong fluorescence emission at band 745 nm and show bright red fluorescence after excited by 800 nm laser. The response of the chemodosimeter is fast (within 30 s) and the chemodosimeter is chemically reversible. The stoichiometry between probe and ions was deduced from Job's plot showed 1:2. Living cell imaging experiment demonstrated that NRhB-BODIPY is an excellent bioimaging agent.