Preparation, characterization, and antimicrobial activities of ZnO nanoparticles/cellulose nanocrystal nanocomposites

Zinc oxide (ZnO) nanoparticles were synthesized within cellulose nanocrystals (CNC) as a new stabilizer by a precipitation method for antimicrobial applications. For fabrication of ZnO/CNC nanocomposites, solutions with different molar ratios of Zn to CNC were prepared in ethanol as the solvent. ZnO/CNC was separated from the suspension and then dried at 120 °C for 1 hour. The nanocomposites were characterized using Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), X-ray diffraction (XRD), transmission electron microscope (TEM), and thermogravimetric (TG) analyses. According to the XRD and TEM results, the ZnO nanoparticles with a hexagonal wurtzite structure were easily prepared and dispersed in the CNC with an average size of less than 20 nm. The average size of the ZnO nanoparticles increased with increasing molar ratio of ZnO to CNC. The best ratio of Zn:CNC was chosen based on the small size of the ZnO nanoparticles that yielded better antimicrobial and thermal properties. The UV-vis absorption spectra of the ZnO/CNC nanocomposites showed absorption peaks in the UV region that were ascribed to the band gap of the ZnO nanoparticles. The antibacterial effects of ZnO/CNC were stronger compared to ZnO nanoparticles

Improvement of phytase biosynthesis by new bacterial isolate, pediococcus pentosaceus c4/1a via continuous cultivation

Phytase producer was selected from five different lactic acid bacteria isolates obtained from the animal faeces sources from laboratory culture collection. From the five isolates, C4/1A showed the highest phytase activity (21.25 U/mL) as compared to others and was identified as PediococcuspentosaceusC4/1A by 16S rRNA gene sequencing. Optimization of medium formulation and culture conditions was conducted by a conventional method (one-factor-at-one-time) using response surface methodology(RSM). Effects of four parameters were studied on the bacterial growth, reducing sugar and phytase productions. The phytase biosynthesis increased from 21.2 U/mL to 42.3 U/mL using the optimized medium formulation and culture conditions. The RSM suggested that yeast extract, glucose, sodium phytate and inoculum size significantly improved by 99.2% production of phytase. Continuous cultivation was carried out at dilution rate ranging from 0.1 h-1 to 0.4 h-1 and the steady-state of P. pentosaceusC4/1A was achieved after five generations and three residence times. The cultivation was carried out for 48 h and the highest productivity of phytase and cell concentration was obtained at dilution rate 0.3 h-1 which resulted in 8.65 U/mL/h and 0.894 g/L/h, respectively. Throughout the cultivation process, production of phytase was improved by 89.3% from shake-flask experiment to 2L bioreactor

Investigation of Pediatric Brucellosis

Background and Aim: Brucellosis (also known as undulant fever, Mediterranean fever, or Malta fever) is a zoonotic infection transmitted to humans from infected animals (sheep, cattle, goats, pigs, camels, or other animals) by ingestion of food products (such as unpasteurized dairy products) or by contact with tissue or fluids.  This disease occurs on average in 11 to 56 percent of children in endemic regions. Despite being long recognized and controllable, the disease still causes substantial morbidity, affecting especially the young population. The objective of this research was to examine the clinical, laboratory results of childhood brucellosis and brucellosis epidemiological features in patients up to 15 years in the province in Pol-e Dokhtar city, Iran. Methods The diagnosis of brucellosis was established on the basis of clinical features, and positive results from Serologic evaluation included Wright test and the 2-mercaptoethanol (2ME) test. This information includes medical records of brucellosis patients in the years 2016 to 2019. SPSS software (version 22.0) was used for the data analysis. Results: Among the patients infected with Brucella, 19 males (70.37%) and 8 females (29.63%) were diagnosed and  11 patients (40.74%) were 5-9 years of age, 10 patients (37%) were 10-15 years of age, and 6 patients (22.26%) were < 5 year of age. Also 27 (100%) patients were from rural regions (the total of affected children) that confirmed direct contact with infected animals in all of them was already established. The most frequent seasons of disease occurrence were summer (33.38%) and winter (29.6%). Conclusion: Considering that 100% of the infection of children has been seen in those who lived in the village, it requires regular vaccination of livestock and proper training in the field of disease prevention. *Corresponding Authors: Faranak Rezaei, Email: [email protected]; Iman Pouladi, Email: [email protected] Please cite this article as: Babaei Z, Azizi abi F, Pouladi I, Rezaei F. Investigation of Pediatric Brucellosis in Pol-e Dokhtar city, Iran. Arch Med Lab Sci. 2020;6:1-4 (e14). https://doi.org/10.22037/amls.v6.3054

Nanosized silver–palm pollen nanocomposite, green synthesis, characterization and antimicrobial activity

Palm pollen (PP) has been widely used in nutrition, pharmaceutical and cosmetic industries. In the present study, we explored the potential of PP in the synthesis of a silver nanoparticle (Ag NP). PP was used as both reducing and stabilizing agent. The Ag/PP nanocomposite was examined by field emission electron microscopy, X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy and zeta potential measurement. The biosynthesized NPs showed surface plasmon resonance centered at 425 nm with an average particle size measured to be 23 nm and a zeta potential of −30.9 mV. Prominent FT-IR signals were obtained and ascribed to phenolic and carbohydrate compounds involved in the formation of the Ag NPs, and proteins which participated in stabilization of the Ag NPs. The biologically synthesized Ag NPs were found to be extremely effective against E. coli (13.8 ± 0.25 mm) with a minimum inhibitory concentration of 20 µg/mL. Thus, such biosynthesized Ag NPs can be used in medicinal applications

Cellulose nanocrystals/ZnO as a bifunctional reinforcing nanocomposite for poly (vinyl alcohol)/chitosan blend films: fabrication, characterization and properties

In this study, cellulose nanocrystals/zinc oxide (CNCs/ZnO) nanocomposites were dispersed as bifunctional nano-sized fillers into poly(vinyl alcohol) (PVA) and chitosan (Cs) blend by a solvent casting method to prepare PVA/Cs/CNCs/ZnO bio-nanocomposites films. The morphology, thermal, mechanical and UV-vis absorption properties, as well antimicrobial effects of the bio-nanocomposite films were investigated. It demonstrated that CNCs/ZnO were compatible with PVA/Cs and dispersed homogeneously in the polymer blend matrix. CNCs/ZnO improved tensile strength and modulus of PVA/Cs significantly. Tensile strength and modulus of bio-nanocomposite films increased from 55.0 to 153.2 MPa and from 395 to 932 MPa, respectively with increasing nano-sized filler amount from 0 to 5.0 wt %. The thermal stability of PVA/Cs was also enhanced at 1.0 wt % CNCs/ZnO loading. UV light can be efficiently absorbed by incorporating ZnO nanoparticles into a PVA/Cs matrix, signifying that these bio-nanocomposite films show good UV-shielding effects. Moreover, the biocomposites films showed antibacterial activity toward the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The improved physical properties obtained by incorporating CNCs/ZnO can be useful in variety uses

Rapid removal of Cu(II) ion by chemically modified rubber wood fiber

This article describes a study of the adsorption conditions of Cu(II) ions onto polyacrylamide-grafted rubberwood fiber. Preparation of the adsorbent was carried out via graft copolymerization of acrylamide (Am) onto rubberwood fiber (RWF), using ceric ammonium nitrate as an initiator. Fourier transform infrared spectroscopy was used to confirm the formation of PAm-g-RWF. Various variables affecting the adsorption capacity such as pH of the solution, adsorption time, initial metal ion concentration, and temperature were investigated. Cu(II) was removed by PAm-g-RWF up to 92% from an initial concentration of 10 mg/L at pH 6.0. Kinetic adsorption data can be described by the second-order equation. Equilibrium parameters for adsorption isotherms of the metal ions on the grafted fiber were obtained using the Langmuir and Freundlich models, and the Langmuir model was found to be in better correlation with the experimental data with a maximum adsorption capacity of 142.85 mg/g. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°), and entropy change (ΔS°) were calculated; the adsorption process was spontaneous and endothermic. The results showed that PAm-g-RWF developed in this study could be an economical and effective adsorbent for application in removal of copper ions from water and wastewater

A combined nucleocapsid vaccine induces vigorous SARS-CD8+ T-cell immune responses

Several studies have shown that cell-mediated immune responses play a crucial role in controlling viral replication. As such, a candidate SARS vaccine should elicit broad CD8+ T-cell immune responses. Several groups of mice were immunized alone or in combination with SARS-nucleocapsid immunogen. A high level of specific SARS-CD8+ T-cell response was demonstrated in mice that received DNA encoding the SARS-nucleocapsid, protein and XIAP as an adjuvant. We also observed that co-administration of a plasmid expressing nucleocapsid, recombinant protein and montanide/CpG induces high antibody titers in immunized mice. Moreover, this vaccine approach merits further investigation as a potential candidate vaccine against SARS

In vitro molecular study of wound healing using biosynthesized bacteria nanocelluse/silver nanocomposite assisted by bioinformatics databases

Background: In recent years, bacterial nanocellulose (BNC) based nanocomposites have been developed to promote healing property and antibacterial activity of BNC wound dressing. Molecular study can help to better understanding about interaction of genes and pathways involved in healing progression. Objectives: The aim of this study was to prepare bacterial nanocellulose/silver (BNC/Ag) nanocomposite films as ecofriendly wound dressing in order to assess their physical, cytotoxicity and antimicrobial properties. The in vitro molecular study was performed to evaluate expression of genes involved in healing of wounds after treatment with BNC/Ag biofilms. Study design, materials, and methods: Silver nanoparticles were formed by using Citrullus colocynthis extract within new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Besides, swelling property and Ag release profile of the nanocomposites were studied. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was studied. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR. Results: Spherical silver nanoparticles with particle size ranging from 20 to 50 nm were synthesized and impregnated within the structure of BNC. The resulting nanocomposites showed significant antibacterial activities with inhibition zones ranging from 7±0.25 to 16.24±0.09 mm against skin pathogenic bacteria. Moreover, it was compatible with human fibroblast cells (HDF) and could promote in vitro wound healing after 48h. Based on bioinformatics databases, the genes of TGF-β1, MMP2, MMP9, CTNNB1, Wnt4, hsa-miR-29b-3p and hsa-miR-29c-3p played important role in wound healing. The nanocomposites had an effect in expression of the genes in healing. Thus, the BNC/Ag nanocomposite can be used to heal wound in a short period and simple manner. Conclusion: This eco-friendly nanocomposite with excellent antibacterial activities and healing property confirming its utility as potential wound dressings

Cytotoxic effects of bio-synthesized zinc oxide nanoparticles on murine cell lines

Zinc oxide nanoparticles (ZnO-NPs) are among the most appropriate metal oxide nanoparticles to exhibit significant potential for treatment properties in a broad spectrum of applications in biomedicine, such as in the treatment of various cancers. The aim of this study was to evaluate the in vitro cytotoxic activity and cellular effects of previously prepared ZnO-NPs using brown seaweed (Sargassum muticum) aqueous extract. Consequently, In vitro anticancer activity was demonstrated in murine cancer cell lines of breast cancer (4T1), lung adenocarcinoma (CRL-1451), colon cancer (CT-26), and acute myelocytic leukemia (WEHI-3). Treated cancer cells with ZnO-NPs for 72 hours demonstrated various levels of cytotoxicity based on calculated IC50 values using MTT assay as follows: 21.7 ± 1.3 μg /mL (4T1), 17.45 ± 1.1 μg /mL (CRL-1451), 11.75 ± 0.8 μg /mL (CT-26) and 5.6 ± 0.55 μg /mL (WEHI-3), respectively. On the other hand, ZnO-NPs treatments for 72 hours showed no toxicity against normal mouse fibroblast (3T3) cell lines. Furthermore, distinct morphological changes were found by utilizing flourescent dyes, as apoptotic population were increased via flowcytometry, while cell cycle block and stimulation of apoptotic proteins were also observed. Additionally, the present study showed that the caspase activations contributed to ZnO-NPs triggered apoptotic death in WEHI-3 cells. Thus, the nature of biosynthesis and the therapeutic potential of ZnO-NPs could prepare the way for further research on the design of green synthesis therapeutic agents, particularly in nanomedicine, for the treatment of cancer

ZnO-Ag core shell nanocomposite formed by green method using essential oil of wild ginger and their bactericidal and cytotoxic effects

In this paper, a novel green method for fabrication of zinc oxide-silver (ZnO-Ag) core-shell nanocomposite using essential oil of ginger (EO-G) is reported. The EO-G played two significant roles in the synthesis process: it could act as a reaction media for the formation of ZnO and reduce Ag+ to Ag0. The bioformed ZnO-Ag nanocomposite was compared with pure biosynthesized ZnO-NPs and characterized by UV–vis spectroscopy, TEM, EDX, XRD and FTIR. The characterization results confirmed that Ag-NPs had been embedded in ZnO hexagonal nanoparticles. Six Gram positive and negative pathogens were used to investigate the antibacterial effects of these samples. Ag-doping improves the bactericidal activity of ZnO-NPs. In vitro cytotoxicity studies on Vero cells, a dose dependent toxicity with non-toxic effect of concentration below 100 μg/mL was shown for ZnO-Ag nanocomposite. The biosynthesized ZnO-Ag nanocomposites were found to be comparable to those obtained from the conventional methods using hazardous materials which can be an excellent alternative for the synthesis of ZnO-Ag using biomass