scholarly journals Gamma Ray-Induced Synthesis of Silver Nanoparticles using Bacterial Cellulose as a Multi-Functional Agent and its Application

Author(s):  
Nasser H. Mohammad ◽  
gamal Mohamed elsherbiny ◽  
Ali A. Hammad ◽  
Ahmed A. Askar ◽  
Salwa A. Abou El Nour

Abstract Antibacterial coatings based on bacterial cellulose (BC) have been widely used in many fields including food packaging and wound dressing. In this study, we aimed to synthesis of colloidal AgNPs and BC/ AgNP composite by using BC as a reducing and capping agent in one step reaction induced by gamma-ray. Bacterial strain Komagataeibacter rhaeticus N1 MW322708 was used for biosynthesis BC by inoculation on Hestrin and Schramm medium and incubated statically at 35 °C for 10 days. BC sheet was formed, harvested, purified, and dried, then used for the synthesis of AgNPs and BC/AgNP by soaked 0.05 g of dried BC in 10ml of 1mM aqueous AgNO3 solution for 2h and then irradiated by gamma-ray under different doses. Color change from yellow to deep brown indicated the synthesis of AgNPs and BC/AgNP. The optical spectra of synthesized AgNPs revealed that the surface plasmon resonance was localized around 420 nm. DLS analysis showed that the mean diameter of AgNPs was 49.5 nm with a -19.36-mV value of zeta potential. TEM images revealed the spherical shape of synthesized AgNPs. The results of FESEM, FTIR, and XRD confirmed the formation of BC/AgNO3 composite. The highly crystalline nature of the BC membrane and BC/AgNP composite was observed in XRD measurements with a crystal size of 5.416 and 5.409 nm, respectively. The antibacterial activity of BC and BC/AgNP against pathogenic bacterial isolated from Pastirma food samples revealed that BC does not show antibacterial activity, while BC/AgNP composite showed antibacterial potency against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Proteus mirabilis, and Escherichia coli, with an inhibition zone of (mm) 9±1, 9±0.57, 10±1.15, 8±0.5 and 7±0.28, respectively. We concluded that this novel method presented in this paper offers a promising route for both AgNPs and BC/AgNP composites synthesis using a green, renewable biopolymer as a multifunctional agent and potential to be applied in the future development of food packing, biomedical instruments, and therapeutics.

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1647
Author(s):  
Gulden Nagmetova ◽  
Anna Berthold-Pluta ◽  
Monika Garbowska ◽  
Askar Kurmanbayev ◽  
Lidia Stasiak-Różańska

Biocellulose, named “the biomaterial of the future”, is a natural and ecologically friendly polymer, produced by selected acetic acid bacteria strains. Biocellulose impregnated with antimicrobial agents can be used as a novel, safe, and biodegradable food packaging material, helping extend the shelf life of some products and may also have the chance to replace typical plastic packaging, which is a big environmental problem these days. This study aimed to evaluate if cellulose impregned with natural oregano essential oil could show antibacterial activity against Cronobacter strains, which can occur in food, causing diseases and food poisoning. Bacterial cellulose was obtained from two acetic bacteria strains, Gluconacetobacter hansenii ATCC 23769 and Komagataeibacter sp. GH1. Antibacterial activity was studied by the disc-diffusion method against chosen Cronobacter strains, isolated from the plant matrix. Oregano essential oil has been shown to penetrate into the structure of bacterial cellulose, and after applying cellulose to the solid medium, it showed the ability to migrate. Biopolymer from the strain K. sp. GH1 was able to better absorb and retain essential oregano oil (OEO) compared to bacterial cellulose (BC) produced by the G. hansenii ATCC 23769. Bacterial cellulose with oregano essential oil from strain Komagataeibacter GH1 showed generally greater inhibitory properties for the growth of tested strains than its equivalent obtained from G. hansenii. This was probably due to the arrangement of the polymer fibers and its final thickness. The largest zone of inhibition of strain growth was observed in relation to C. condimenti s37 (32.75 mm ± 2.8). At the same time, the control sample using filter paper showed an inhibition zone of 36.0 mm ± 0.7. A similar inhibition zone (28.33 mm ± 2.6) was observed for the C. malonaticus lv31 strain, while the zone in the control sample was 27.1 mm ± 0.7. Based on this study, it was concluded that bacterial cellulose impregnated with oregano essential oil has strong and moderate antimicrobial activity against all presented strains of the genus Cronobacter isolated from plant matrix. Obtained results give a strong impulse to use this biopolymer as ecological food packaging in the near future.


2019 ◽  
Vol 25 (34) ◽  
pp. 3692-3701 ◽  
Author(s):  
Hanif Ullah ◽  
Munair Badshah ◽  
Alexandra Correia ◽  
Fazli Wahid ◽  
Hélder A. Santos ◽  
...  

Background: Bacterial cellulose (BC) has recently attained greater interest in various research fields, including drug delivery for biomedical applications. BC has been studied in the field of drug delivery, such as tablet coating, controlled release systems and prodrug design. Objective: In the current work, we tested the feasibility of BC as a drug carrier in microparticulate form for potential pharmaceutical and biomedical applications. Method : For this purpose, drug-loaded BC microparticles were prepared by simple grinding and injection moulding method through regeneration. Model drugs, i.e., cloxacillin (CLX) and cefuroxime (CEF) sodium salts were loaded in these microparticles to assess their drug loading and release properties. The prepared microparticles were evaluated in terms of particle shapes, drug loading efficiency, physical state of the loaded drug, drug release behaviour and antibacterial properties. Results: The BC microparticles were converted to partially amorphous state after regeneration. Moreover, the loaded drug was transformed into the amorphous state. The results of scanning electron microscopy (SEM) showed that microparticles had almost spherical shape with a size of ca. 350-400 μm. The microparticles treated with higher drug concentration (3%) exhibited higher drug loading. Keeping drug concertation constant, i.e., 1%, the regenerated BC (RBC) microparticles showed higher drug loading (i.e., 37.57±0.22% for CEF and 33.36±3.03% for CLX) as compared to as-synthesized BC (ABC) microparticles (i.e., 9.46±1.30% for CEF and 9.84±1.26% for CLX). All formulations showed immediate drug release, wherein more than 85% drug was released in the initial 30 min. Moreover, such microparticles exhibited good antibacterial activity with larger zones of inhibition for drug loaded RBC microparticles as compared to corresponding ABC microparticles. Conclusion : Drug loaded BC microparticles with immediate release behaviour and antibacterial activity were fabricated. Such functionalized microparticles may find potential biomedical and pharmaceutical applications.


2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Nguyen Phuc Quan 1,2 ◽  
Tran Quoc Vinh 1 ◽  
Kieu Thi My Yen 1 ◽  
Le Vu Khanh Trang 2 ◽  
Nguyen Minh Ly 2 ◽  
...  

The synthesis of silver nanoparticles (Ag NPs) has been carried out using different methods, mainly by biological and chemical methods; however, comparing antibacterial activity of Ag NPs synthesized by these methods has not been conducted before. In this study, silver nanoparticles (Ag NPs) were synthesized by methods using reducing agent NaBH4/carboxymethyl cellulose (CMC) and fungal strain Trichoderma asperellum (T.asperellum). The formation of silver nanoparticles was observed visually by color change and identified by Ultraviolet-visible (UV – vis) spectroscopy. The transmission electron microscopy (TEM) image illustrated almost nanoparticles with spherical shape and average diameter of 4.1 ± 0.2 nm and 2.1 ± 0.2 nm of samples produced from chemical reduction and biosynthesis respectively. Both samples after 180 days storing have been separated lightly, but the agglomeration and absorbance peak shifting were not observed which proved the high stability of synthesized Ag NPs. Antimicrobial activity against human bacterial pathogen Escherichia coli (E. coli) showed that the inhibition zone produced by “biosynthesis” and “chemical reduction” Ag NPs were 3.17 cm and 2.42 cm respectively. With nanoparticles size smaller than 2 mm, antibacterial activity of “biosynthesis” Ag NPs against E. coli was 31 % higher than “chemical reduction” Ag NPs, although the concentration of Ag NPs produced by biosynthesis was about 10-fold less.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2569
Author(s):  
Mia Kurek ◽  
Nasreddine Benbettaieb ◽  
Mario Ščetar ◽  
Eliot Chaudy ◽  
Maja Repajić ◽  
...  

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.


Author(s):  
Eric Kwabena Droepenu ◽  
Ebenezer Aquisman Asare ◽  
Boon Siong Wee ◽  
Rafeah Binti Wahi ◽  
Frederick Ayertey ◽  
...  

Abstract Background Various parts of Anacardium occidentale plant possess curative qualities like antidiabetic, anti-inflammatory, antibacterial, antifungal, and antioxidant. Aqueous extract of this plant leaf was used in biosynthesizing zinc oxide (ZnO) nanoaggregates using two precursors of zinc salt (zinc acetate dihydrate [Zn(CH3COO)2∙2H2O] and zinc chloride [ZnCl2]). The synthesized ZnO samples were used in a comparative study to investigate the antibacterial activity against selected Gram-positive and Gram-negative microbes [Staphylococcus aureus, Exiguobacterium aquaticum (Gram +ve) and Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii (Gram −ve)]. The synthesized ZnO nanoaggregates from the two precursors were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive x-ray spectroscopy (EDX) techniques. Results Micrographs of SEM and TEM confirmed nanoparticles agglomerated into aggregates. While spherical nanoaggregates were identified in samples prepared from Zn(CH3COO)2∙2H2O, flake-like structures were identified in samples synthesized from ZnCl2. Particle size determined by TEM was 107.03 ± 1.54 nm and 206.58 ± 1.86 nm for zinc acetate dihydrate and zinc chloride precursors respectively. ZnO nanoaggregate synthesized using zinc acetate as precursor gave higher antibacterial activity than its counterpart, zinc chloride with K. pneumonia recording the highest inhibition zone of 2.08 ± 0.03 mm (67.53%) whereas S. aureus recorded the least inhibition zone of 1.06 ± 0.14 mm (34.75%) for ZnO nanoaggregate from zinc chloride precursor. Also, antibacterial activity increases with increasing concentration of the extract in general. However, A. baumannii, E. aquaticum, and K. pneumoniae did not follow the continuity trend with regards to the 250 ppm and 500 ppm concentrations. Conclusion Biosynthesis of ZnO nanoaggregates using aqueous extract of A. occidentale leaf from zinc acetate dihydrate and zinc chloride as precursors was successful with the formation of nanospheres and nanoflakes. The study suggested that A. occidentale sp. could be an alternative source for the production of ZnO nanoparticles and are efficient antibacterial compounds against both Gram +ve and Gram −ve microbes with its promising effect against infectious bacteria.


2021 ◽  
Vol 12 (5) ◽  
pp. 645-649
Author(s):  
Yu Gu ◽  
Yuqing Qiao ◽  
Yusen Meng ◽  
Ming Yu ◽  
Bowu Zhang ◽  
...  

Herein, we report for the first time the synthesis of polypyrrole copolymers with good solvent-dispersibility under gamma-ray irradiation at room temperature in air.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 584
Author(s):  
Shalendra Kumar ◽  
Faheem Ahmed ◽  
Nagih M. Shaalan ◽  
Osama Saber

Bio-inspired synthesis is a novel and attractive environmentally friendly route to generating inorganic materials. In this work, the preparation of CeO2 NPs using egg white and investigation of their antibacterial properties both in liquid and solid growth medium against Escherichia coli and Staphylococcus aureus bacteria were reported. The CeO2 nanoparticles were characterized using X-ray diffraction (XRD), Field emission transmission electron microscope (FETEM), UV-Vis, Raman, and antibacterial measurements. The results from XRD and TEM analysis showed that the prepared nanoparticles were a single phase in the nano regime (5–7 nm) with spherical shape and uniform size distribution. Optical properties reflected the characteristics peaks of CeO2 in the UV-Vis range with a bandgap ~2.80 eV. The antibacterial activity of the synthesized NPs was achieved under ambient conditions with different bacteria and the results showed that the properties were different for both the bacteria. The highest activity with an inhibition zone of about 22 mm against S. aureus was obtained as compared with the 19 mm zone of inhibition obtained with E.coli. This finding will be of major significance that indicates a possibility to develop CeO2 NPs as antibacterial agents against extensive microorganisms to control and prevent the spread and persistence of bacterial infections.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Mocanu ◽  
Gabriela Isopencu ◽  
Cristina Busuioc ◽  
Oana-Maria Popa ◽  
Paul Dietrich ◽  
...  

AbstractThis 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.


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