Fine‐Tuning Plasmon‐Molecule Interactions in Gold‐BODIPY Nanocomposites: The Role of Chemical Structure and Noncovalent Interactions

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.

Gold–BODIPY Nanoparticles with Luminescence and Photosensitization Properties for Photodynamic Therapy and Cell Imaging

“…All experiments were carried out as described previously . Field emission scanning electron microscopy (FESEM) images were captured using a Bruker Nano GmbH Gemini SEM 500 field emission scanning electron microscope.…”

“…Syntheses of BODIPYs, nanocomposites, organic nanoparticles, and pristine gold nanoparticles were carried out as reported earlier. ,, For the synthesis of multichromophoric nanocomposites NC3 , 1 mL of HAuCl 4 (2.5 mM) was added to 7 mL of l -tryptophan (25 mM) in water. After stirring for a few minutes, a solution of 1 and 2 in acetone (1 mL each from 2.5 mM stock solutions) was added upon which the solution turned brown-orange.…”

“…However, as the support matrixes rarely interact electronically with the photosensitizer, they seldom aid in overcoming the aggregation-caused quenching phenomenon. On the other hand, the usage of metal nanoparticles aids not only in the self-assembly process but also in modulating the photophysical properties. , Gold nanoparticles are known to have low toxicity and a tunable absorption profile that are dependent on their size and shape and are thus attractive …”

Ternary host-guest complexes with rapid exchange kinetics and photoswitchable fluorescence

“…We hypothesized that cage C should randomly bind two copies of each of these structurally similar molecules, making the formation of ternary complexes feasible (Scheme 1D). It is well known that, on the one hand, the optical properties of BODIPYs 23,[45][46][47][48] (and other dyes [49][50][51][52][53] ) are strongly dependent on their supramolecular environment; on the other hand, when placed in close proximity, anthracenes can undergo a fast [4+4] cycloaddition reaction, [54][55][56][57][58] making the BODIPY/PAH combination ideally suited to investigate the exchange dynamics in host-guest inclusion complexes.…”

Effective Singlet Oxygen Sensitizers Based on the Phenazine Skeleton as Efficient Light Absorbers in Dye Photoinitiating Systems for Radical Polymerization of Acrylates

“…The study of reactive oxygen species is crucial for several groups of scientists, including photochemists, biologists, and physiologists [ 2 , 26 , 27 , 28 , 29 , 30 ]. The search for new, efficient singlet oxygen sensitizers seems to be important because of the positive and negative role of singlet oxygen for humans.…”