Bacterial cellulose films with ZnO nanoparticles and propolis extracts: Synergistic antimicrobial effect

Abstract

This study aimed to obtain possible materials for future antimicrobial food packaging applications based on biodegradable bacterial cellulose (BC). BC is a fermentation product obtained by Gluconacetobacter xylinum using food or agricultural wastes as substrate. In this work we investigated the synergistic effect of zinc oxide nanoparticles (ZnO NPs) and propolis extracts deposited on BC. ZnO NPs were generated in the presence of ultrasounds directly on the surface of BC films. The BC-ZnO composites were further impregnated with ethanolic propolis extracts (EEP) with different concentrations.The composition of raw propolis and EEP were previously determined by gas-chromatography mass-spectrometry (GC-MS), while the antioxidant activity was evaluated by TEAC (Trolox equivalent antioxidant capacity). The analysis methods performed on BC-ZnO composites such as scanning electron microscopy (SEM), thermo-gravimetrically analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX) proved that ZnO NPs were formed and embedded in the whole structure of BC films. The BC-ZnO-propolis films were characterized by SEM and X-ray photon spectroscopy (XPS) in order to investigate the surface modifications. The antimicrobial synergistic effect of the BC-ZnO-propolis films were evaluated against Escherichia coli, Bacillus subtilis, and Candida albicans. The experimental results revealed that BC-ZnO had no influence on Gram-negative and eukaryotic cells.

Antimicrobial Activity of Zinc Oxide Nano/Microparticles and Their Combinations against Pathogenic Microorganisms for Biomedical Applications: From Physicochemical Characteristics to Pharmacological Aspects

“…Antimicrobial polymeric biomaterials or films are used as additive composites in ZnO NP/MP combinations for enhanced antimicrobial activity against pathogenic microorganisms. Recently studied antibiotic biomaterials or films [ 26 , 28 ] in ZnO NPs/MPs combinations included chitosan [ 28 , 82 , 84 ], silk sericin [ 84 ], gelatin [ 91 ], gallic acid [ 28 ], hydroxyapatite [ 83 , 119 ], alginate [ 83 ], polyethyleneglycol (PEG) [ 120 ], biopolymer K [ 27 ], carrageenan [ 27 ], bacterial cellulose [ 121 , 122 ], propolis extract [ 121 ], curcumin [ 84 , 123 , 124 ], graphene [ 84 , 85 ], graphene oxide (GO) [ 86 , 87 , 125 ], reduced graphene oxide (rGO), and cotton [ 88 , 126 , 127 , 128 , 129 ]. In general, they enhanced the antimicrobial activity of ZnO NPs/MPs and overcame formulation challenges of ZnO NPs/MPs in manufacturing beads or films and covering surfaces for coating.…”

Probing Lithium-Ion Battery Electrolytes with Laboratory Near-Ambient Pressure XPS

“…Laboratory NAP-XPS measurements were done with an EnviroESCA (SPECS GmbH, Berlin, Germany) [17][18][19][20]. The monochromatic Al Kα X-ray source is separated from the measurement chamber by a silicon nitride window, and the hemispherical energy analyzer is under ultra-high vacuum (<1 × 10 −8 mbar) due to a three-stage differential pumping system between the analysis section and analyzer.…”

Bacterial Nanocellulose—A Biobased Polymer for Active and Intelligent Food Packaging Applications: Recent Advances and Developments

“…Another approach to impart bactericidal features to BNC matrices was the incorporation of metal ions and oxides (e.g., silver, gold, copper, platinum, ZnO, TiO 2 , MgO) [ 90 ]. The study of Mocanu et al [ 115 ] presented the synergistic antimicrobial effect of zinc oxide nanoparticles and propolis extracts deposited on BNC. Zinc oxide and other metal oxides nanoparticles exhibited significant activity against food pathogens by generating reactive oxygen species and reducing the integrity of their cell membrane [ 116 ].…”