BOPHY‐Fullerene C₆₀ Dyad as a Photosensitizer for Antimicrobial Photodynamic Therapy

Abstract

A novel BOPHY–fullerene C60 dyad (BP‐C60) was designed as a heavy‐atom‐free photosensitizer (PS) with potential uses in photodynamic treatment and reactive oxygen species (ROS)‐mediated applications. BP‐C60 consists of a BOPHY fluorophore covalently attached to a C60 moiety through a pyrrolidine ring. The BOPHY core works as a visible‐light‐harvesting antenna, while the fullerene C60 subunit elicits the photodynamic action. This fluorophore–fullerene cycloadduct, obtained by a straightforward synthetic route, was fully characterized and compared with its individual counterparts. The restricted rotation around the single bond connecting the BOPHY and pyrrolidine moieties led to the formation of two atropisomers. Spectroscopic, electrochemical, and computational studies disclose an efficient photoinduced energy/electron transfer process from BOPHY to fullerene C60. Photodynamic studies indicate that BP‐C60 produces ROS by both photomechanisms (type I and type II). Moreover, the dyad exhibits higher ROS production efficiency than its individual constitutional components. Preliminary screening of photodynamic inactivation on bacteria models (Staphylococcus aureus and Escherichia coli) demonstrated the ability of this dyad to be used as a heavy‐atom‐free PS. To the best of our knowledge, this is the first time that not only a BOPHY–fullerene C60 dyad is reported, but also that a BOPHY derivative is applied to photoinactivate microorganisms. This study lays the foundations for the development of new BOPHY‐based PSs with plausible applications in the medical field.

Light-Activated Antibacterial Polymeric Surface Based on Porphycene

“…The scavenger reacts with 1 O 2 to produce the endoperoxide derivative, which decomposes spontaneously (see Figure S7). Thus, the formation of 1 O 2 can be monitored by following the decrease of the absorption band of DPBF at 414 nm …”

“…Thus, the formation of 1 O 2 can be monitored by following the decrease of the absorption band of DPBF at 414 nm. 60 The polymeric film P-Pc-Cbz was dipped in an airequilibrated solution of DPBF in DMF, and it was then exposed to visible light irradiation (455−800 nm). In addition, the photooxidation reaction of the trapping reagent was also assessed and compared using a solution of Pc-Cbz in DMF.…”

Tuning the Molecular Structure of Corroles to Enhance the Antibacterial Photosensitizing Activity

“…Samples were excited at 572 nm and fluorescence emission was detected between 600 and 800 nm. Fluorescence quantum yields (Φ F ) were calculated according to previously published work (see Equation (S1) ) [ 18 , 29 ], using Co as a reference (Φ F = 0.10 in toluene) [ 30 ]. Fluorescence excitation spectra were recorded between 360 and 700 nm at an emission wavelength of 710 nm.…”

“…Singlet oxygen photosensitized by corrole derivatives was detected according to previous works [ 18 , 29 ]. Samples, containing 9,10-dimethylantracene (DMA) and the corresponding corrole (A = 0.1 at 606 nm) in toluene (2 mL), were irradiated with light (λ irr = 606 nm, 1.15 mW/cm 2 ) under aerobic conditions.…”

“…Thus, the obtention and characterization of new PSs for antimicrobial photodynamic therapy are of great relevance for the development of this area. Even though a wide variety of families of PSs have been applied to photokill pathogenic microbes [ 13 , 14 , 15 , 16 , 17 , 18 ], the most used are those based on porphyrins. The main reason relies on the high synthetic versatility of this kind of tetrapyrrolic macrocycles, which allows tuning the properties of PSs according to the needs.…”