A highly sensitive and selective fluorescein-based fluorescence probe for Au3+ and its application in living cell imaging

•A new fluorescein-based fluorescent probe for detection of Au3+ was synthesized.•This probe exhibits highly selective and sensitive response toward gold(III) ion in aqueous solution.•The selective fluorescent response was attributed to an irreversible CN bond hydrolysis induced by Au3+.•The probe is cell-permeable and can be used to detect Au3+ within living cells. A new fluorescein-based fluorescent probe for the detection of Au3+ has been developed. This probe was derived from 4′,5′-fluoresceindicarboxaldehyde and exhibited highly selective and sensitive response toward gold(III) ions in aqueous solution. There is a good linear relationship between the fluorescence intensity at 523nm and the concentrations of Au3+ ranging from 0μM to 60μM, which makes it effective for the detection of Au3+. The limit of detection (LOD) was evaluated to be 0.07μM based on S/N=3. The fluorescence enhancement was attributed to the irreversible CN bond hydrolysis that occurred to this probe in the presence of Au3+, generating the fluorescent 4′,5′-fluoresceindicarboxaldehyde. Furthermore, the imaging experiments indicated that this probe is cell-permeable and can be used to detect Au3+ within living cell.