Essential oil–encapsulated SiO2 nanocapsules for the treatment of bacterial biofilms formed on food‐contact surfaces

Abstract Litsea cubeba essential oil (EO)‐encapsulated SiO 2 (SiO 2 ‐EO) nanocapsules were fabricated by in situ biosilicification for the treatment of biofilms on food‐contact surfaces. By optimizing the synthesis conditions (0.5 mg/mL EO and 50 mM silicic acid), SiO 2 ‐EO nanocapsules exhibited a uniform size distribution (150–200 nm) with a distinct core–shell structure. The characterization of nanocapsules was elucidated using a scanning electron microscope (SEM), transmission electron microscope, Fourier transform infrared, and x‐ray diffraction analyses. The minimal inhibitory concentrations of SiO 2 ‐EO nanocapsules were 5 and 1.25 mg/mL for Escherichia coli and Staphylococcus aureus , respectively. Compared to free EO, the SiO 2 ‐EO nanocapsules showed more significant inhibition activity against both Gram‐negative and Gram‐positive bacterial biofilms. Confocal experiments and SEM demonstrated that the nanocapsules efficiently penetrate biofilms within 30 min and deliver EO to destroy the membrane structure of bacteria. Eventually, SiO 2 ‐EO nanocapsules were also applied to four kinds of food‐contact surfaces. The populations in biofilms exposed to 2.5 mg/mL of nanocapsules decreased 1.51–1.56 log CFU/cm 2 and 2.15–2.22 log CFU/cm 2 for E. coli and S. aureus , respectively. This study provides an innovative strategy to treat bacterial biofilms with EO‐based nanocomposites.