Construction of magnetic response nanocellulose particles to realize smart antibacterial of pickering emulsion

Smart antibacterial Pickering emulsion can respond to the stimulation of environmental conditions to control the release of antibacterial agents, protecting the quality and safety of food. In this study, Fe₃O₄ was grafted on the cellulose nanocrystal (CNC) via ultrasound-assisted in situ co-precipitation to synthesize the magnetic cellulose nanocomposite particles. When the ratio of FeCl₃ and FeCl₂ was 1.5:1, the prepared particles CNC/Fe_1.5 exhibited the maximum saturation magnetization intensity of 54.98 emu/g and good emulsion stability, which was used to emulsify oregano essential oil (OEO) to fabricate smart antibacterial Pickering emulsion with magnetically responsive ability. The emulsion with the oil-water ratio of 3:7 and the particle concentration of 0.3 wt% showed the excellent stability and sensitive responsiveness of magnetic. The OEO released rapidly within 0-8 h followed by the slow release when the emulsion was stimulated by 0.2 T, 0.4 T and 0.6 T magnetic field. The antibacterial rate of the emulsion was close to 100 % against both E. coli and L. monocytogenes at magnetic field with 0.4 T and 0.6 T in 12 h, achieving the smart antimicrobial. The prepared smart antibacterial Pickering emulsion would provide a novel material and have the potential in food packaging.