Light-Deactivated Fluorescent Probes (FLASH-Off) for Multiplexed Imaging.

Highly multiplexed, cyclic fluorescence imaging has advanced our understanding of the biology, evolution, and complexity of human diseases. Currently available cyclic methods still have considerable limitations including the need for long quenching times and extensive wash steps. Here, we report a new series of fluorochromes that can be efficiently inactivated by a single light pulse (∼405 nm) by means of a photo-immolating triazene linker. Upon UV-light irradiation, the rhodamines are cleaved off from the antibody conjugates and undergo a fast intramolecular spirocyclization that inherently switches off their fluorescence emission without the need to wash or add exogenous chemicals. We show that these switch-off probes are fast, highly controllable, biocompatible, and allow spatiotemporal quenching control of live and fixed samples.