A Visible-Light-Regulated Chloride Transport Channel Inspired by Rhodopsin.

Inspired by the light-regulating capabilities of naturally occurring rhodopsin, we have constructed a visible-light-regulated Cl- -transport membrane channel based on a supramolecular host-guest interaction. A natural retinal chromophore, capable of a visible-light response, is used as the guest and grafted into the artificial channel. Upon introduction of an ethyl-urea-derived pillar[6]arene (Urea-P6) host, threading or de-threading of the retinal and selective bonding of Cl- can be utilized to regulate ion transport. Based on the visible-light responsiveness of the host-guest interaction, Cl- transport can be regulated by visible light between ON and OFF states. Visible-light-regulated Cl- transport as a chemical model permits to understand comparable biological ion-selective transport behaviors. Furthermore, this result also supplies a smart visible-light-responsive Cl- transporter, which may have applications in natural photoelectric conversion and photo-controlled delivery systems.