Visible light-induced synergic antimicrobial activity of silver nanoparticles/methylene blue nanohybrids encapsulated in chitosan and pluronic polymers

Author(s)

Silva Lima, Giovanni Alexsander ; Guerini, Guilherme Goncalves ; de Vasconcellos, Suzan Pantaroto ; Pellosi, Diogo Silva

• Document type: Journal article
• Source: CHEMICAL PAPERS; v. 77, n. 1, p. 13-pg., 2022-09-27.

Abstract

Despite the extraordinary advances, bacterial infections continue to be one of the main concerns in modern medicine due the development of antibiotic multidrug resistant strains. In this scenario, the development of new antimicrobial agents that can act by multiple targets avoiding resistance development is urgent. Among several approaches, the use of silver nanoparticles (AgNP) and photodynamic therapy are highlighted. However, these modalities alone have not been enough. Therefore, in this work, we integrated AgNP and the photosensitizing agent methylene blue (MB) favorable photophysical properties into Pluronic P123 and chitosan polymers creating an AgNP/MB nonohybrid structure as demonstrated by UV-Vis, particle size and transmission electron microscopy analysis. These were carefully engineered to tune the distance between AgNP-MB aiming to enhance material photophysics through resonant coupling of MB photosensitizer and AgNP. The nanohybrid allowed a significant enhancement of hypertoxic singlet oxygen (O-1(2)) generation, which in turn promoted the inactivation of S. aureus and E. coli bacteria, under red LED light irradiation. Chou-Talalay statistics demonstrated that when AgNP and MB are working together, especially in P123 formulations, a strong synergistic action occurs mainly due to the so-called double-enhancement mechanism, which improves the in situ Ag+ and O-1(2) release, inducing bacteria to inactivation. These results showed the importance of the rational design for engineering new and efficient multifunctional nanomaterials, indicating that Pluronic-loaded AgNP/MB nanohybrids can act as a next-generation of antimicrobial nanoplatforms against bacterial infections. [GRAPHICS] . (AU)

• FAPESP's process: 18/11451-7 - Visible light-assisted synthesis and morphological optimization of silver nanoparticles
• Grantee: Giovanni Alexsander Silva Lima
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 19/01604-3 - Light-assisted synthesis of silver nanoparticles/photosensitizers in polymeric matrix and its synergic application in phototherapies
• Grantee: Diogo Silva Pellosi
• Support Opportunities: Regular Research Grants