Mesoporous silica shell in a core@shell nanocomposite design enables antibacterial action with multiple modes of action

Abstract

Core@shell structured nanocomposites have received significant attention for their synergistic mode of antibacterial action. Identification of the accommodated unit’s function in the core@shell nanostructure is necessary in order to determine whether antibacterial synergism against bacterial cell growth that is provided within the same core@shell structure. Herein, a novel nanostructure(s) composed of a cerium oxide core and a porous silica shell (CeO2@pSiO2) accomodating curcumin and lectin was prepared, and the antibacterial synergism provided by the nanocomposite was identified. The resulting spherical-shaped CeO2@pSiO2 nanostructure allowed accommodation of curcumin loading (9 w/w%) and a lectin (concanavalin A) coating (15 w/w%). The antibacterial synergism was tested using a minimal inhibitory concentration assay against an Escherichia coli Gram-negative bacterial strain. Furthermore, the mechanisms of bacterial cell disruption induced by the curcumin-loaded and concanavalin A-coated CeO2@pSiO2 core@shell structure, namely the nanoantibiotic (nano-AB) and its design components, were identified. Our findings reveal that the mesoporous silica shell around the CeO2 core within the nano-AB design aids the accommodation of curcumin and concanavalin A and promotes destruction of bacterial cell motility and the permeability of the inner and outer bacterial cell membranes. Our findings strongly indicate the promising potential of a mesoporous silica shell around nanoparticles with a CeO2 core to provide synergistic antibacterial treatment and attack bacterial cells by different mechanisms of action.