Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg2+ detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb3+ from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg2+ into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg2+. As a kind of Hg2+ nanosensor, the probe exhibited excellent selectivity for Hg2+ and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg2+ in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. [Display omitted] •Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process.•AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition.•Hypersensitive detection of Hg2+ was achieved based on time-resolved spectroscopy.