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

Coupling of surface plasmons on metal nanoparticles with the electronic states of organic chromophores is known to result in hybrid states having unique photophysical properties. Previously, we had demonstrated that plasmon–molecule coupling in gold–BODIPY nanocomposites was effective for singlet oxygen production for photodynamic therapy (PDT). Herein, we show that gold nanoparticles can function as a matrix on which Förster resonance energy transfer (FRET) is facilitated between two electronically distinct BODIPY chromophores in a multichromophoric nanocomposite, which opens up radiative pathways, thereby making the nanocomposite fluorescent. Additionally, photoinduced hot electron transfer between BODIPY and gold allows for the efficient photosensitized generation of singlet oxygen. Our approach to achieving simultaneous FRET and plasmon–molecule interactions on gold nanoparticles is unique and hitherto unknown and makes the multichromophoric nanocomposite a potential candidate for photodynamic therapy and cell imaging.