Enhancement of antioxidant activity of levan through the formation of nanoparticle systems with metal ions

Highly efficient degradation of basic dyes using gold-coated nature-based supermagnetic iron oxide nanoparticles as eco-friendly nanocatalysts

Nowadays, organic dyes are prevalent components in wastewater discharges due to their extensive use in various industries, posing a significant threat to public health across different organisms. As a result, wastewater treatment has become an indispensable requirement. In this study, we synthesized supermagnetic iron oxide (Fe3O4 NPs) and gold-iron oxide bimetallic nanoparticles (Au@Fe3O4 BNPs) using an eco-friendly method that involved natural compounds extracted from brown Egyptian propolis. We employed UV-visible spectroscopy, FTIR, XRD, VSM, SEM, HRTEM, EDX, Zeta potential and XPS techniques to examine the optical characteristics, chemical structure, crystalline structure, magnetic properties, morphology, size, and chemical composition of these biosynthesized nanoparticles. Furthermore, these nanoparticles were used as nanocatalysts for the removal of cationic dyes. The photocatalytic results indicated high efficiency in the removal of methylene blue (MB), crystal violet (CV), and malachite green (MG) dyes from aqueous solutions using Fe3O4 NPs and Au@Fe3O4 BNPs. The removal rates of MB, CV, and MG were about 95.2% in 70 min, 99.4% in 50 min, and 96.2% in 60 min for Fe3O4 NPs, and 97.1% in 50 min, 99.1% in 30 min, and 98.1% in 50 min for Au@Fe3O4 BNPs, respectively. The study also assessed the potential anti-radical properties of the extract, Fe3O4 NPs, and Au@Fe3O4 BNPs using the DPPH assay, and the results demonstrated their antioxidant activity. Finally, these Fe3O4 NPs and Au@Fe3O4 BNPs have the potential to serve as efficient antioxidants and photocatalysts for removing basic dyes from water.

Green synthesis of copper ions nanoparticles functionalized with rhamnolipid as potential antibacterial agent for pathogenic bacteria

Copper-based nanoparticles possess broad-spectrum antibacterial activity against both gram-positive and gram-negative bacteria, making them a cost-effective alternative to other metal-based nanoparticles. The development of eco-friendly copper based nanopaticles using biodegradable and non-toxic biosurfactants, such as rhamnolipid is being explored in this study. In the present study, Cu(I)-rhamnolipid nanoparticles (Cu(I)-Rl Nps) was prepared by coprecipitation method. The structural analysis by using FTIR and XRD techniques revealed that Cu(I)-Rl Nps was successfully produced, as indicated by the detectable of ionic and covalent-coordinations bond between rhamnolipid and Cu(I) ions. Further analysis using TEM, PSA and ZPA suggest that the resulted Cu(I)-Rl Nps have spherical shape with the diameter range of 141.7-536.3 nm and the surface charge of -30 mV, respectively. The antibacterial activity of Cu(I)-Rl Nps surpassed that of the copper-based nanoparticles, free-state Cu(I) ions and rhamnolipid, which was determined by MIC/MBC methods. The Cu(I)-Rl Nps inhibition to the growth of Bacillus subtilis ATCC 6633 (Gram-positive) gave the MIC/MBC values of 19/19 μg/mL, while the copper-based nanoparticles, free-state Cu(I) ions and rhamnolipid gave the MIC/MBC value of 1250/2500, 1250/1250, 62/62 μg/mL, respectively. Further test on Escherichia coli ATCC 6538 (Gram-negative) showed that the Cu(I)-Rl Nps gave the MIC/MBC value of 78/78 μg/mL, while the copper-based nanoparticles, free-state Cu(I) ions and rhamnolipid gave the MIC/MBC value of 2500/2500, 2500/2500, 2000/2000 μg/mL, respectively. The increased antibacterial activity of Cu(I)-Rl Nps was due to the synergistic effects between Cu(I) and rhamnolipid.

Elaboration of Nanostructured Levan-Based Colloid System as a Biological Alternative with Antimicrobial Activity for Applications in the Management of Pathogenic Microorganisms

Considering the documented health benefits of bacterial exopolysaccharides (EPSs), specifically of bacterial levan (BL), including its intrinsic antimicrobial activity against certain pathogenic species, the current study concentrated on the development of active pharmaceutical ingredients (APIs) in the form of colloid systems (CoSs) containing silver nanoparticles (AgNPs) employing in-house biosynthesized BL as a reducing and capping agent. The established protocol of fermentation conditions implicating two species of lactic acid bacteria (LAB), i.e., Streptococcus salivarius K12 and Leuconostoc mesenteroides DSM 20343, ensured a yield of up to 25.7 and 13.7 g L-1 of BL within 72 h, respectively. An analytical approach accomplished by Fourier-transform infrared (FT-IR) spectroscopy allowed for the verification of structural features attributed to biosynthesized BL. Furthermore, scanning electron microscopy (SEM) revealed the crystalline morphology of biosynthesized BL with a smooth and glossy surface and highly porous structure. Molecular weight (Mw) estimated by multi-detector size-exclusion chromatography (SEC) indicated that BL biosynthesized using S. salivarius K12 has an impressively high Mw, corresponding to 15.435 × 104 kilodaltons (kDa). In turn, BL isolated from L. mesenteroides DSM 20343 was found to have an Mw of only 26.6 kDa. Polydispersity index estimation (PD = Mw/Mn) of produced BL displayed a monodispersed molecule isolated from S. salivarius K12, corresponding to 1.08, while this was 2.17 for L. mesenteroides DSM 20343 isolate. The presence of fructose as the main backbone and, to a lesser extent, glucose and galactose as side chain molecules in EPS hydrolysates was supported by HPLC-RID detection. In producing CoS-BL@AgNPs within green biosynthesis, the presence of nanostructured objects with a size distribution from 12.67 ± 5.56 nm to 46.97 ± 20.23 was confirmed by SEM and energy-dispersive X-ray spectroscopy (EDX). The prominent inhibitory potency of elaborated CoS-BL@AgNPs against both reference test cultures, i.e., Pseudomonas aeruginosa, Escherichia coli, Enterobacter aerogenes, and Staphylococcus aureus and those of clinical origin with multi-drug resistance (MDR), was confirmed by disc and well diffusion tests and supported by the values of the minimum inhibitory and bactericidal concentrations. CoS-BL@AgNPs can be treated as APIs suitable for designing new antimicrobial agents and modifying therapies in controlling MDR pathogens.

Cytotoxicity and Antibacterial Efficacy of AgCu and AgFe NanoAlloys: A Comparative Study

Although Ag nanoparticles (NPs) have been widely applied in daily life and in biomedical and industrial fields, there is a demand for Ag-based bimetallic nanoalloys (NAs), such as AgCu and AgFe, due to their enhanced antibacterial efficacy and reduced Ag consumption. In this work, we present a comparison study on the antibacterial efficacy and cytotoxicity rates of Ag NPs and AgCu and AgFe NAs to L929 mouse fibroblast cells using the CCK-8 technique based on the relative cell viability. The concept of the minimum death concentration (MDC) is introduced to estimate the cytotoxicity to the cells. It is found that the minimum inhibitory concentrations (MICs) of the NPs against E. coli and S. aureus decrease with the addition of both Cu and Fe. There is a strong correlation between the MDC and MIC, implying that the mechanisms of both antibacterial efficacy and cytotoxicity are similar. The enhanced antibacterial efficacy to bacteria and cytotoxicity toward the cell are attributed to Ag+ release. The following order is found for both the MIC and MDC: AgFe < AgCu < Ag NPs. However, there is no cytotoxicity to the L929 cells for AgFe and AgCu NAs at their MIC Ag concentrations against S. aureus.

The Use of Saccharomyces cerevisiae Supplemented with Intracellular Magnesium Ions by Means of Pulsed Electric Field (PEF) in the Process of Bread Production

Bread was supplemented with magnesium through an addition of yeasts subjected to the effect of PEF at optimised parameters to obtain the maximum bioaccumulation of magnesium in cells. Bread produced with the use of yeasts supplemented with magnesium by means of PEF was characterised by its highest content, at 39.3 mg/100 g, which was higher by 50% and 24%, respectively, compared to the control bread sample with an admixture of yeasts cultured without any addition of magnesium and with no PEF treatment and to the control bread sample with an admixture of yeasts cultured with an addition of magnesium but no PEF treatment. The addition of yeasts supplemented with magnesium using PEF in bread production did not cause any statistically significant changes in the chemical composition of any of the analysed samples. However, statistically significant changes were noted in the technological properties of breads produced with an admixture of yeasts supplemented with magnesium by means of PEF treatment. An increase of moisture to 54.03 ± 0.29% led to a reduction of the total baking loss. No statistically significant differences were noted in the bread volume in samples K1, K2, and P, varying from 239 to 269 cm3/100 g.

A new approach to nanocomposite carbohydrate polymer films: Levan and chia seed mucilage

Plastic pollution is increasing day by day and the search for new, environmentally friendly products continues. Herein, for the first time, different degrees of mucilage were obtained from chia seeds and the film-forming behavior of levan biopolymer with these mucilages was investigated. Glycerol and sorbitol were used as plasticizers in the film design. Films prepared with sorbitol were characterized physically, mechanically and morphologically. The antioxidant and antimicrobial effects of the films were examined. The films formed as nanocomposites of levan and chia seed mucilages obtained at different temperatures (25 °C, 55 °C and 80 °C) exhibited structurally and mechanically different properties. It was observed that the films obtained with chia mucilages and levan preserved their antibacterial properties but lost their antifungal properties. In addition, quorum sensing property of the mucilage obtained at 55 °C during the investigation of the antibacterial property was reported for the first time with this study. The levan-based chia seed mucilages films obtained have the potential to be used in industrial and medical fields, and the nature-friendly nature of these films is very important for our green world.

Bioavailability and antioxidant activity of nanotechnology-based botanic antioxidants

Botanic bioactive substances have issues with their solubility, stability, and oral bioavailability in the application, which could be improved by nanotechnologies. In another hands, green synthesis of nanoparticles (NPs) with plant extract is also a promising technology for preparation of NPs due to its safety advantage, yet the bioactive botanic substances that could be more than the assistant of the green synthesis of NPs. Based on the above concerns, this review summarized the preparation of botanic NPs with various plant extract, their solubility, stability, and oral bioavailability; specific attention has been paid to the botanic Ag/Au NPs, their capacity of antioxidant, bioavailability, antimicrobial, anti-inflammatory, and anticancer.

Biosynthesis of nano bimetallic Ag/Pt alloy from Crocus sativus L. extract: Biological efficacy and catalytic activity

In this project, silver‑platinum (AgPt) nanoparticles were prepared by using the Crocus sativus L. plant ethanolic extract. The AgPt nanoparticles were characterized by applying the various method as ultraviolet-visible and infrared spectroscopy, electron microscopy, and X-ray diffraction analysis. The morphology structural indicated that the AgPt nanoparticles were spherical particles with diameter about 36.0 nm. The FTIR spectroscopy shows the efficient stabilization of the AgPt nanoparticles by phytoconstituents. The Ag and AgPt nanoparticles have polyphenolic content, lower than the flavonoids and proanthocyanins contents. The AgPt nanoparticles depicted the highest antioxidant properties compared to the Ag nanoparticles and ascorbic acid. The results showed that the AgPt nanoparticles had a high antioxidant properties. In addition, the AgPt nanoparticles demonstrated the substantial antimicrobial and cytotoxic activities against pathogenic microbes and MCF-7 breast cancer cell line. The environmental chemistry analysis depicts that methyl orange can be degraded from water by catalytic degradation process with sodium borohydride. The AgPt nanoparticles were prosperous in catalytic degrading methyl orange following a first order kinetic model.