Photooxidation-Driven Purely Organic Room-Temperature Phosphorescent Lysosome-Targeted Imaging

Area of Science:

• Supramolecular Chemistry
• Biomaterials Science
• Photochemistry

Background:

• Host-guest complexation is crucial for developing functional supramolecular assemblies.
• Phosphorescent materials are valuable for bioimaging and sensing applications.
• Developing stimuli-responsive materials for cellular imaging is an active research area.

Purpose of the Study:

• To construct a host-guest-binding-induced phosphorescent supramolecular assembly.
• To investigate the photophysical properties and imaging capabilities of the assembly.
• To demonstrate dual organelle-targeted imaging in living cells.

Main Methods:

• Utilized cucurbit[8]uril as a host and an anthracene-conjugated bromophenylpyridinium as a guest.
• Investigated host-guest complexation and its effect on fluorescence emission.
• Induced photooxidation of the anthryl group to anthraquinone.
• Observed the emergence of green phosphorescence and dual organelle targeting (nuclei and lysosomes).

Main Results:

• Formation of a linear supramolecular assembly enhancing red fluorescence via charge-transfer interactions.
• Conversion to a homoternary inclusion complex upon photooxidation, yielding strong green phosphorescence.
• Achieved distinct dual organelle-targeted imaging in nuclei and lysosomes post-UV irradiation.
• Demonstrated photooxidation-driven, purely organic room-temperature phosphorescence.

Conclusions:

• The cucurbit[8]uril host effectively induces supramolecular assembly formation with enhanced photophysical properties.
• Photooxidation triggers a significant shift from fluorescence to phosphorescence, enabling dual-color imaging.
• This strategy offers a versatile platform for supramolecular organelle identification and tracking biological events in live cells.