CuFe2O4/lignin-based carbon composited photothermal and photodynamic agents for synergetic antibacterial therapy.

Bacterial infection has become the second leading cause of death in the world. Exploring a new highly antibacterial catalyst to replace traditional antibacterial agent is crucial for the society development of human beings. In this study, CuFe2O4/Lg-based carbon composited catalysts were rationally constructed by facile hydrothermal method. Lignin-derived carbon with enormous oxygen-containing functional group was beneficial to anchor CuFe2O4 nanoparticles. The close contact interface between CuFe2O4 and Lignin-based carbon material was expected to extend the range of optical absorption and promote the separation and transportation of photogenerated carriers. Under NIR (980 nm, 1.5 W/cm2) light irradiation, the as-prepared CuFe2O4/Lg (20 µg/mL) exhibited excellent photo/photothermal synergetic in vitro (against Escherichia coli and Staphylococcus aureus) and in vivo (against Staphylococcus aureus-infected mouse wound model) antibacterial performance. Furthermore, the cell count assay kit 8 (CCK-8 kit) demonstrated the good biocompatibility of this material. On the basis of the experimental results, a possible antibacterial mechanism based on the synergetic photothermal and photodynamic therapies was proposed. This work presented a lignin- derived carbon-based highly efficient antibacterial disinfection agent with desirable biosafety.

Polysaccharide- and protein-based edible films combined with microwave technology for meat preservation.

To reduce food-borne bacterial infection caused by food spoilage, developing highly efficient food packing film is still an urgent need for food preservation. Herein, microwave-assisted antibacterial nanocomposite films CaO2@PVP/EA/CMC-Na (CP/EC) were synthesized using waste eggshell as precursor, egg albumen (EA) and sodium carboxymethylcellulose (CMCNa) as matrix by casting method. The size of CaO2@PVP (CP) nanoparticles with monodisperse spherical structures was 100-240 nm. When microwave and CP nanoparticles (0.05 mg/mL) were treated for 5 min, the mortality of E. coli and S. aureus could reach >97 %. Under microwave irradiation (6 min), the bactericidal rate of 2.5 % CP/EC film against E. coli and S. aureus reached 98.6 % and 97.2 %, respectively. After adding CP nanoparticles, the highest tensile strength (TS) and elongation at break (EB) of CP/EC film reached 19.59 MPa and 583.43 %, respectively. At 18 °C, the proliferation of bacterial colonies on meat can be significantly inhibited by 2.5 % CP/EC film. Detailed characterization showed that the excellent meat preservation activity was due to the synergistic effect of dynamic effect generated by ROS and thermal effect of microwave. This study provides a promising approach for the packaging application of polysaccharide- and protein-based biomass nanocomposite antibacterial edible films.