ABSTRACT
Herein, carvacrol (CRV) and modified cellulose nanocrystal-zinc oxide (CNC-ZnO) were incorporated into a poly (lactic acid) (PLA) matrix to prepare a PLA-based composite film using a simple solution casting method to achieve antimicrobial effects for application in antimicrobial food packaging. Compared with films obtained from neat PLA, the PLA@CRV20%@CNC-ZnO3% composite film shows better performance in terms of mechanical properties, ultraviolet (UV) blocking, and antimicrobial effects. The PLA composites containing CRV and 3 wt% CNC-ZnO blends exhibit improved tensile strength (21.8 MPa) and elongation at break (403.1 %) as well as excellent UV resistance. In particular, CRV and the CNC-ZnO hybrid endow the obtained PLA composite films with a synergistic antibacterial effect, resulting in good antibacterial properties for microbes, such as Escherichia coli, Staphylococcus aureus and Aspergillus niger. The diameters of the inhibition zone of the PLA@CRV20%@CNC-ZnO3% composite films against E. coli, S. aureus, and A. niger were 4.9, 5.0, and 3.4 cm, respectively. Appling the PLA@CRV20%@CNC-ZnO3% composite film as an antibacterial food packaging material, the storage period for strawberries was considerably extended. This study provides a theoretical basis for developing new organic/inorganic composite antimicrobial film materials from PLA.
Subject(s)
Anti-Bacterial Agents , Cellulose , Cymenes , Food Packaging , Nanoparticles , Polyesters , Zinc Oxide , Zinc Oxide/chemistry , Zinc Oxide/pharmacology , Polyesters/chemistry , Cymenes/chemistry , Cymenes/pharmacology , Cellulose/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Nanoparticles/chemistry , Food Packaging/methods , Staphylococcus aureus/drug effects , Nanocomposites/chemistry , Escherichia coli/drug effects , Tensile Strength , Microbial Sensitivity Tests , Aspergillus niger/drug effectsABSTRACT
The spread of many infectious diseases relies on aerosol transmission to the respiratory tract. Here we design an intranasal mask comprising a positively-charged thermosensitive hydrogel and cell-derived micro-sized vesicles with a specific viral receptor. We show that the positively charged hydrogel intercepts negatively charged viral aerosols, while the viral receptor on vesicles mediates the entrapment of viruses for inactivation. We demonstrate that when displaying matched viral receptors, the intranasal masks protect the nasal cavity and lung of mice from either severe acute respiratory syndrome coronavirus 2 or influenza A virus. With computerized tomography images of human nasal cavity, we further conduct computational fluid dynamics simulation and three-dimensional printing of an anatomically accurate human nasal cavity, which is connected to human lung organoids to generate a human respiratory tract model. Both simulative and experimental results support the suitability of intranasal masks in humans, as the likelihood of viral respiratory infections induced by different variant strains is dramatically reduced.
