Polydopamine@SnS/g-C3N4 heterojunction photocatalyst: Insight into visible-light-induced reactive oxygen species (ROS)-mediated antibacterial and antimold activities

Abstract

Herein, we aimed to fabricate poly(dopamine) coated tin sulfide/graphitic-carbon nitride (PDA@SnS/g-C3N4) photocatalyst as a targeted bioactive nano-agent for the growth control of antimicrobial resistants’ using a combined solvothermal and chemically oxidative polymerization of dopamine synthesis technique. The as-synthesized materials were systematically characterized for crystallographic, morphological, and spectroscopic analysis, revealed that the g-C3N4 component is composed of discrete nanoparticles that couple with SnS nanoparticles anchoring g-C3N4 nanosheets and poly(dopamine) molecules as capping agents, resulting in tight bilayer contact interfaces. Therefore, effective charge carrier separation was observed in the final product upon visible-light illumination. When used as an antimicrobial agent, the resultant PDA@SnS/g-C3N4 composite strongly inactivated the growth of the Gram-positive–Enterococcus faecalis, Gram-negative–Pseudomonas aeruginosa, and two mold strains–Aspergillus fumigatus, Aspergillus flavus upon 0.60 J dose of visible-light treatment at a minimum concentration of 45 μg·ml−1, respectively. Moreover, radical scavenger experiments confirm the •O2–, and h+ initial species in the system. Importantly, no antimicrobial effect is recorded for the non-irradiated samples, indicating that the developed materials are not innately virulent in the lack of visible light and can be safely used to control the growth and survivorship of both detrimental molds and bacteria in reducing the risk of healthcare-associated infections.