A reversible multi-stimuli-responsive fluorescence probe and the design for combinational logic gate operations

Here, a novel multi-stimuli-responsive fluorescence probe is developed by incorporating spiropyran group into the coumarin-substituted polydiacetylene (PDA) vesicles. The fluorescence of PDA can be turned on upon heating, and can be quenched upon exposure to UV light irradiation or pH stimuli owing to the fluorescene resonance energy transfer (FRET) between the red-phase PDA and the open merocyanine (MC) form of spiropyran. Moreover, we have designed and experimentally realized a set of logic gate operations for the first time based on the fluorescence modulation of the designed system upon thermal, photo, and pH stimuli. This novel type of resettable logic gates augur well for practical applications in information storage, optical recording, and sensing in complicated microenvironments. The interconversion between the colored and colorless form of spiropyran (close-to-opened isomerization of spiropyran when exposure to UV irradiation or upon pH stimuli) can act as the driving force to modulate the fluorescence of the red-phase PDA owing to the fluorescene resonance energy transfer (FRET) between the red-phase PDA and the open merocyanine (MC) form of spiropyran. Because of the reversible chemical nature of the spiropyran group and the reversible thermochromatic transition of the hybrid PDA vesicles, the fluorescence could be reversibly switched on and off.