Ionic Liquid Vesicle-Confined Curcumin: Tunable Excited-State Dynamics and Interaction with Glutathione-Capped Nanoclusters

Encapsulation within vesicular aggregates offers a promising strategy to overcome curcumin's limited bioavailability while providing a tunable microenvironment to modulate its photophysical properties. Herein, we develop two size-variant vesicular aggregates to improve bioavailability and modulate the ultrafast excited-state dynamics of curcumin. Time-resolved anisotropy reveals that larger vesicles exhibit greater structural rigidity, thereby systematically slowing curcumin's excited-state intramolecular proton transfer (ESIPT) dynamics. Furthermore, we synthesize gold and silver nanoclusters using bioactive peptide reduced glutathione (GSH) and incorporate them into vesicular architectures to probe their interactions with curcumin and to examine alterations in the ultrafast dynamics of curcumin. The excited-state lifetime of curcumin decreases upon the addition of both nanoclusters through the Förster resonance energy transfer (FRET) process. We effectively develop a FRET system using curcumin and nanoclusters within vesicular aggregates, broadening our understanding and expanding its scope for drug delivery and bioimaging applications.