A cyanobenzo[a]phenoxazine-based near infrared lysosome-tracker for in cellulo imaging.

A cyanobenzo[a]phenoxazine-based pH probe with pKa = 5.0 exhibits OFF–ON emission at 625–850 nm upon excitation at 600 nm in aqueous buffers. The in cellulo imaging experiments with HeLa cells indicate that the probe can serve as a lysosome-specific probe under red light excitation (633 nm) with near infrared emission (650–790 nm). [ABSTRACT FROM AUTHOR]