A two-photon fluorescent probe for real-time monitoring of autophagy by ultrasensitive detection of the change in lysosomal polarity.

The first two-photon probe, Lyso-OC, was proposed for use in monitoring cell autophagy by detection of the change in the lysosomal polarity during the membrane fusion process of autophagy. The Lyso-OC probe exhibited desirable optical properties and a detection signal that was selective to the polarity change. More importantly, Lyso-OC displayed real-time monitoring of autophagy in living cells.