Self‐Assembled Binaphthyl‐Bridged Amphiphilic AABB Phthalocyanines: Nanostructures for Efficient Antimicrobial Photodynamic Therapy

Abstract

Herein, the photodynamic activity of phthalocyanine (pc)‐assembled nanoparticles against bacterial strains is demonstrated. The photosensitizers (PS) studied in this work are two chiral ZnIIPcs (PS‐1 and PS‐2), with an AABB geometry (where A and B refer to differently substituted isoindole constituents). They contain differently functionalized, chiral binaphthyloxy‐linked A isoindole units, which determine the hydrophobicity of the system, and cationic methyl pyridinium moieties in the other two isoindoles to embody hydrophilicity. Both compounds have the ability to self‐assemble into nanoparticles in aqueous media and have proved efficient in the photo‐inactivation of Staphylococcus aureus and Escherichia coli, selected as models of Gram‐positive and Gram‐negative bacteria. The average size of the nanoparticles was determined by substitution at the binaphthyl core and, in turn, influences the toxicity of the PS. Thus, PS‐1, presenting a nonsubstituted binaphthyl core, forms larger nanoparticles with a larger cationic surface than the octyl‐functionalized PS‐2. Although both PSs present similar structure and photophysical features, the self‐assembled nanostructures of PS‐1 are more effective at killing both types of strain, showing an outstanding photo‐inactivation capacity with the Gram‐negative E. coli.

Regulation of photo triggered cytotoxicity in electrospun nanomaterials: role of photosensitizer binding mode and polymer identity

“…Although SymPc presented a broader and blue-shifted absorption in H 2 O, its ROS generation was somehow higher. We assume that the two PSs form different types of aggregates determined not only by repulsion between positively charged pyridinium units but also, more importantly, by solvophobic forces, 38 in which the polyethylene glycol substituent may play an important role. Overall, the high ROS generating ability and positive charge of both PSs points to great potential for a broad spectrum of antibacterial and antiviral activity.…”

Self‐Assembled Porphyrinoids: One‐Component Nanostructured Photomedicines

“…A novel archetype of amphiphilic Pc‐based PS relies on a binaphthyloxy‐linked A 2 B 2 ZnPc core structure (with A and B coding for two differently functionalized isoindoles), [72] functionalized with pyridinium‐substituents at two of the isoindole to provide water solubility. [73] In particular, two PS endowed with different amphiphilic character were prepared, either attaching two octyl chains at the binaphthyl unit (PS‐2) or keeping the ring bare (PS‐1) (Figure 10 C). These molecules showed ability to form positively charged and stable nanoparticles in aqueous solution, and to disassemble in more hydrophobic media.…”

The Surprisingly Positive Effect of Zinc-Phthalocyanines With High Photodynamic Therapy Efficacy of Melanoma Cancer

“…Phthalocyanine (Pc) derivatives are photoactive compounds (ideally absorb light in the UV–Vis spectrum), especially in the red to near-infrared regions, which allow a higher tissue penetration and, consequently, a better PDT response ( Camerin et al, 2010 ; Vummidi et al, 2013 ; Lo et al, 2020 ; Lopes-Nunes et al, 2020 ; Galstyan, 2021 ; Janas et al, 2021 ; Ribeiro and Lourenço, 2021 ). However, Pc macrocycles have weak solubility in various organic solvents or in aqueous media, and therefore, to minimize this drawback, it is essential to incorporate “bio”motifs, such as biologics or charged groups, including cationic pyridinium units on their structure to improve their amphiphilicity ( Lourenço et al, 2015 ; Lourenço et al, 2019 ; Gamelas et al, 2020 ; Lopes-Nunes et al, 2020 ; Pereira et al, 2020 ; Revuelta-Maza et al, 2020 ; Revuelta‐Maza et al, 2021 ). Different peripheral substituents (α- and/or ß -positions) and their number usually give distinct photophysical, photochemical, and PDT results ( Halaskova et al, 2021 ).…”