Porphyrin−BODIPY Dyad: Enhancing Photodynamic Inactivation via Antenna Effect

Abstract

AbstractA porphyrin−BODIPY dyad (P−BDP) was obtained through covalent bonding, featuring a two‐segment design comprising a light‐harvesting antenna system connected to an energy acceptor unit. The absorption spectrum of P−BDP resulted from an overlap of the individual spectra of its constituent parts, with the fluorescence emission of the BODIPY unit experiencing significant quenching (96 %) due to the presence of the porphyrin unit. Spectroscopic, computational, and redox investigations revealed a competition between photoinduced energy and electron transfer processes. The dyad demonstrated the capability to sensitize both singlet molecular oxygen and superoxide radical anions. Additionally, P−BDP effectively induced the photooxidation of L‐tryptophan. In suspensions of Staphylococcus aureus cells, the dyad led to a reduction of over 3.5 log (99.99 %) in cell survival following 30 min of irradiation with green light. Photodynamic inactivation caused by P−BDP was also extended to the individual bacterium level, focusing on bacterial cells adhered to a surface. This dyad successfully achieved the total elimination of the bacteria upon 20 min of irradiation. Therefore, P−BDP presents an interesting photosensitizing structure that takes advantage of the light‐harvesting antenna properties of the BODIPY unit combined with porphyrin, offering potential to enhance photoinactivation of bacteria.