Stimulating antibacterial activities of graphitic carbon nitride nanosheets with plasma treatment

Abstract

As a widely studied photoactive antibacterial nanomaterial, the intrinsic antibacterial traits of graphitic carbon nitride (g-C₃N₄) as a two-dimensional nanomaterial have not been reported so far. Herein, nitrogen-plasma-treated g-C₃N₄ (N-g-C₃N₄) nanosheets and their influence on bactericidal characteristics are investigated. Bactericidal rates of more than 99% have been successfully achieved for 8 kinds of foodborne pathogenic bacteria by N-g-C₃N₄ with 8 h incubation in the dark. The achieved rates are percentage wise 10 times higher than those for pristine g-C₃N₄. Cell rupture caused by direct mechanical contact between g-C₃N₄ nanosheets and cell membranes is observed. X-ray photoelectron spectroscopy revealed a substantial loss of surface defects and nitrogen vacancies in N-g-C₃N₄. Molecular dynamics simulations further indicated that the largely sealed defects of N-g-C₃N₄ enhanced the electrostatic attraction between inherent pores and lipid heads; thus, further insertion of N-g-C₃N₄ was promoted, resulting in enhanced antibacterial activity. This study establishes novel fabrication and application strategies for carbon based antibacterial nanomaterials.