Imaging of living organisms and determination of real water samples using a rhodamine-based Fe(III)-induced fluorescent probe

In this study, we designed and synthesized a novel rhodamine-based and Fe3+ -induced fluorescent probe (RBNC) and characterized by H-1 NMR, C-13 NMR and ESI-MS. RBNC exhibits highly specific detection of Fe3+ with little interference to other coexisting cations and anions in the MeOH/H2O (1:1, v/v, HEPES, 0.5 mM, pH = 7.35) solution. After adding Fe3+, the color change is obvious and the fluorescence intensity is rapidly enhanced. The reversibility of RBNC to Fe3+ was achieved by adding Na4P2O7. In addition, RBNC has a higher binding constant (1.17 x 10(4) m(-1)) and a lower detection limit (0.157 mu M). RBNC can also be used to monitor trace Fe(3+)in actual water samples. Bioimaging experiments demonstrated that RBNC is feasible for imaging in living organisms when it is used for biological detection. MTT assays indicated that RBNC is non-toxic in cells at low concentrations.