A highly selective turn-on fluorescent chemosensor for Al3+ imaging in living cells via through-bond energy transfer

PSI-BDP showed almost no fluorescence due to the introduction of oxygen donors through the PeT process. Upon addition of Al3+, the PeT was switched off by coordination of Al3+, and the cassette PSI-BDP underwent through-bond energy transfer (TBET) to release strong fluorescence. PSI-BDP was highly selective to Al3+ and the detection limit for Al3+ reached 1 mu M. The fluorescence intensity of PSI-BDP for Al3+ remained unaffected over a wide pH span of 5-9 and PSI-BDP detection of Al3+ could therefore be applied to a biologically relevant pH range. PSI-BDP was used as a fluorescence turn-on chemosensor for Al3+ in HepG2 cells, indicating its potential application for studying the effect of Al3+ in biological systems.