A DPA-based highly selective and sensitive fluorescent probe for mercuric ions and its imaging in living cells

Based on the 2,2-dipicolylamine (DPA) receptor and naphthalimide fluorophore, three fluorescent probes, RDPA, MDPA and VDPA have been developed for the recognition of mercuric ions. Among them, VDPA, bearing a diglycol group in the imine chain, exhibits good water solubility, and high selectivity towards mercuric ions in PBS water solution. With DPA as the receptor, VDPA showed very high affinity and sensitivity towards He2+, and the binding constant and detection limit were calculated to be 2.8 x 10(10) M-1 and 5.49 nM, respectively. The MTT assay and living cell imaging experiments suggested that the probe VDPA has potential application for detecting Hg2+ in living cells.