Nanoarchitectonics of nitric oxide releasing supramolecular structures for enhanced antibacterial efficacy under visible light irradiation

Light-controlled therapies offer a promising strategy to prevent and suppress infections caused by numerous bacterial pathogens. Excitation of exogenously supplied photosensitizers (PS) at specific wave-lengths elicits levels of reactive oxygen intermediates toxic to bacteria. Porphyrin-based supramolecular nanostructure frameworks (SNF) are effective PS with unique physicochemical properties that have led to their widespread use in photomedicine. Herein, we developed a nitric oxide (NO) releasing, biocompat-ible, and stable porphyrin-based SNF (SNF-NO), which was achieved through a confined noncovalent self -assembly process based on pi-pi stacking. Characterization of the SNFs via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed the formation of three-dimensional, well-defined octahedral structures. These SNF-NO were shown to exhibit a red shift due to the noncova-lent self-assembly of porphyrins, which also show extended light absorption to broadly cover the entire visible light spectrum to enhance photodynamic therapy (PDT). Under visible light irradiation (46 J cm (2)), the SNF generates high yields of singlet oxygen (O-1(2)) radicals, hydroxyl radicals (HO), superoxide radicals (O-2(.)), and peroxynitrite (ONOO-) radicals that have shown potential to enhance antimicrobial photody-namic therapy (APDT) against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli (E. coli). The resulting SNFs also exhibit significant biofilm dispersion and a decrease in biomass production. The combination of robust photosensitizer SNFs with nitric oxide-releasing capabilities is dynamic in its ability to target pathogenic infections while remaining non-toxic to mammalian cells. The engineered SNFs have enormous potential for treating and managing microbial infections. (c) 2023 Elsevier Inc. All rights reserved.

Automated summary

Light-controlled therapies using porphyrin-based supramolecular nanostructure frameworks (SNFs) show promise in preventing and suppressing bacterial infections. The SNFs offer extended light absorption and release high yields of reactive oxygen intermediates under visible light irradiation, enhancing antimicrobial photodynamic therapy (APDT). Furthermore, the SNFs exhibit significant biofilm dispersion and can target pathogenic infections without harming mammalian cells, making them a potential treatment for microbial infections.