Natural melanin nanoparticle-based photothermal film for edible antibacterial food packaging.

Although nanocomposite films had shown excellent potential in antibacterial food packaging, their potential harmful impact limits their further application in reality. Therefore, exploring a Generally Recognized As Safe (GRAS) nanomaterial that has antibacterial ability is the pioneer for the fabrication of a real edible nanocomposite-based antibacterial packaging film. Herein, for the first time by using the natural nanostructure extracted from cuttlefish ink, an edible antibacterial food packaging with high safety were constructed. The natural melanin nanoparticles (NMPs) in cuttlefish ink have good photothermal conversion ability. As such, by incorporating with natural pectin (PC) film and with near infrared (NIR) irradiation triggering, the results show that PC/NMPs films perform high-efficiency and short-term bactericidal activity against foodborne pathogenic bacteria, including thermotolerant Listeria monocytogenes. The sterilization rate could reach more than 90 % within only 5 min. Also, this nanocomposite film showed better mechanical properties, thermal stability and barrier properties than the neat pectin film. Antibacterial test on food sample also proved the good antibacterial ability of the PC/NMPs films. Therefore, exploring GRAS natural functional nanocomposite film is expected to be the effective way to promote edible nano-antibacterial packaging.

Efficient and reusable photocatalytic river water disinfection by addictive graphitic carbon nitride/magnesium oxide nano-onions with particular "nano-magnifying glass effect".

Photocatalytic disinfection is a promising way to combat bacterial pollution in the water environment. Inefficient use of visible light and undirected diffusion of reactive oxygen species (ROS) reduce photocatalytic disinfection efficiency. Herein, inspired by the concentrating effect of convex lens, photocatalysts with particular "nano-magnifying glass effect" (TCNMgNOs) were designed by embedding magnesium oxide with "converge effect" into the tailored hierarchical triple-shell porous g-C3N4 with "one light multi-purpose effect" to boost the visible-light utilization. Meanwhile, the ATPase hydrolysis homeostasis of bacteria was destroyed by TCNMgNOs to achieve the targeted movement of ROS. The results confirmed that the photocatalytic sterilization efficiency of TCNMgNOs was amplified by 30 times over g-C3N4, which was achieved by focusing visible light, multiple reflecting visible light and light transmission within the porous thin shells as well as the "addictive sterilization mechanism". The sterilization efficiency still maintains 98.8 % (15 min) after 6 rounds recycling and reusing in practical river water disinfection. A novel pathway for fighting against microbial contaminants in natural water was explored.