Morphological, physical, antimicrobial and release properties of ZnO nanoparticles-loaded bacterial cellulose films

Bacterial cellulose (BC) monolayer and multilayer films, incorporating 5 wt.% ZnO nanoparticles (NPs) have been obtained. Ultrasound (US) irradiation (40 kHz) was applied during ZnO-BC nanocomposites preparation. X-ray diffraction (XRD) patterns showed that ZnO NPs were crystallized in their pure phase. SEM scanning electron microscopy (SEM) results indicated that US treatment causes to decrease ZnO particle size, forming a stable hybrid nanostructure and evenly distributed ZnO NPs coated BC nanofibers. ZnO NPs enhanced the mechanical properties and diminished water vapor permeability and moisture absorption of BC films. Antibacterial activity of ZnO-BC films against Staphylococcus aureus was more than Escherichia coli. The antibacterial activity was enhanced with the utilization of US irradiation. The ZnO release was influenced by films composition; the multilayer and US treated films being promising in order to achieve controlled release of ZnO. Results suggest that ZnO-BC films may be used as controlled release antimicrobial food active packaging. (C) 2016 Elsevier Ltd. All rights reserved.