A novel colorimetric and OFF-ON fluorescent chemosensor based on fluorescein derivative for the detection of Fe3+ in aqueous solution and living cells

In this work, we have developed a novel benzothiazole-functionalized fluorescein fluorescent Sensor 1 which displays highly selective and sensitive OFF-ON fluorescence response and naked-eye color change to Fe3+ in aqueous solution at pH 7.2. The association constant and detection limits of 1 for Fe3+ were estimated to be 1.085 × 105 M−1 and 7.4 nM. Living cell fluorescence imaging experiments demonstrated that 1 exhibits low cytotoxicity and cell-membrane permeability, which makes it capable of Fe3+ imaging in living Hep G2 cells.150