ABSTRACT
Strong coupling between localized surface plasmons and molecular absorptions leads to remarkable changes in the photophysical properties of dye-loaded metal nanoparticles. Here, we report supramolecular nanocomposites consisting of BODIPY, tryptophan, and gold nanoparticles, and investigate the effect of structural variations on their photophysical properties. Our results indicate that the photostability and photosensitization properties of the nanocomposites depend on the chemical composition of the BODIPY molecules. The singlet oxygen quantum yield of the nanocomposites NC1 (BODIPY, B1 bearing a single methyl group) and NC3 (BODIPY, B3 with 5 methyl and 2 iodo groups) were 0.46 and 0.42, respectively, which were significantly higher compared to their individual components. Ultrafast spectroscopy studies revealed that the migration of photoexcited BODIPY electrons to the plasmonic photoexcitation allowed electron transfer into the singlet oxygen states, thereby leading to efficient generation of singlet oxygen.
ABSTRACT
Design of photosensitizers capable of generating singlet oxygen is crucial for the success of photodynamic therapy, and biocompatible supramolecular systems are emerging in this area. We report a supramolecular nanocomposite consisting of BODIPY, tryptophan and gold nanoparticles. While the individual components in isolation were inactive, the nanocomposite was found to be photostable and exhibited efficient photosensitization properties.
