Synthesis of Tungsten Oxide, Iron Oxide, and Copper-Doped Iron Oxide Nanocomposites and Evaluation of Their Mixing Effects with Cyromazine against Spodoptera littoralis (Boisduval).

Nanotechnology research is emerging as a cutting-edge technology, and nanocomposites have played a significant role in pest control. Therefore, the present study focuses on the synthesis of tungsten oxide (WO3), iron oxide (magnetic nanoparticle, MNP), and copper-doped iron oxide (MNP-Cu) nanocomposites and explores the different effects of their binary combinations with the insecticide cyromazine against Spodoptera littoralis. The synthesized nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. None of the tested nanomaterials showed any toxicity against the different stages of S. littoralis. Larval and pupal durations increased with increasing cyromazine and nanomaterial concentrations. The longest larval and pupal durations were recorded under treatment with the mixture of cyromazine (100 mg/L) + MNP-Cu (500 mg/L); the survival periods were 23.5 and 15.6 days, compared with 10.8 and 7.7 days in the control, respectively. The percentages of pupation and adult emergence were negatively affected by all treatments. Among the 500 mg/L nanomaterial combinations, only cyromazine (25 mg/L) and WO3 (500 mg/L) resulted in adult emergence (at a rate of 27.3%). Some abnormalities in the S. littoralis stages were observed following treatment with the tested materials. The glutathione S-transferase and alpha-esterase enzyme activities in S. littoralis were significantly increased after treatment with cyromazine, followed by cyromazine/MNP-Cu combinations. The quantitative polymerase chain reaction (Q-PCR) data showed that all treated insects had a higher immune response than the control. Finally, mixes of nanocomposites and cyromazine may be suggested as viable alternatives for S. littoralis management.

Scaling-up strategies for controllable biosynthetic ZnO NPs using cell free-extract of endophytic Streptomyces albus: characterization, statistical optimization, and biomedical activities evaluation.

In this study, we identified a suitable precursor and good cellular compartmentalization for enhancing bioactive metabolites to produce biosynthetic zinc oxide nanoparticles (ZnO NPs). An effective medium for cultivating endophytic Streptomyces albus strain E56 was selected using several optimized approaches in order to maximize the yield of biosynthetic ZnO NPs. The highest biosynthetic ZnO NPs yield (4.63 g/L) was obtained when pipetting the mixed cell-free fractions with 100 mM of zinc sulfate as a precursor. The generation of biosynthetic ZnO NPs was quickly verified using a colored solution (white color) and UV-Visible spectroscopy (maximum peak, at 320 nm). On a small scale, the Taguchi method was applied to improve the culture medium for culturing the strain E56. As a result, its cell-dry weight was 3.85 times that of the control condition. And then the biosynthesis of ZnO NPs (7.59 g/L) was increased by 1.6 times. Furthermore, by using the Plackett-Burman design to improve the utilized biogenesis pathway, the biosynthesis of ZnO NPs (18.76 g/L) was increased by 4.3 times. To find the best growth production line, we used batch and fed batch fermentation modes to gradually scale up biomass output. All kinetics of studied cell growth were evaluated during fed-batch fermentation as follows: biomass yield was 271.45 g/L, yield coefficient was 94.25 g/g, and ZnO NPs yield was 345.32 g/L. In vitro, the effects of various dosages of the controllable biosynthetic ZnO NPs as antimicrobial and anticancer agents were also investigated. The treatments with controllable biosynthetic ZnO NPs had a significant impact on all the examined multidrug-resistant human pathogens as well as cancer cells.

Extracellular biosynthesis, OVAT/statistical optimization, and characterization of silver nanoparticles (AgNPs) using Leclercia adecarboxylata THHM and its antimicrobial activity.

BACKGROUND: The biosynthesis of silver nanoparticles (AgNPs) is an area of interest for researchers due to its eco-friendly approach. The use of biological approaches provides a clean and promising alternative process for the synthesis of AgNPs. We used for the first time the supernatant of Leclercia adecarboxylata THHM under optimal conditions to produce AgNPs with an acceptable antimicrobial activity against important clinical pathogens. RESULTS: In this study, soil bacteria from different locations were isolated and screened for their potential to form AgNPs. The selected isolate, which was found to have the ability to biosynthesize AgNPs, was identified by molecular methods as Leclercia adecarboxylata THHM and its 16S rRNA gene was deposited in GenBank under the accession number OK605882. Different conditions were screened for the maximum production of AgNPs by the selected bacteria. Five independent variables were investigated through optimizations using one variable at a time (OVAT) and the Plackett-Burman experimental design (PBD). The overall optimal parameters for enhancing the biosynthesis of AgNPs using the supernatant of Leclercia adecarboxylata THHM as a novel organism were at an incubation time of 72.0 h, a concentration of 1.5 mM silver nitrate, a temperature of 40.0 °C, a pH of 7.0, and a supernatant concentration of 30% (v/v) under illumination conditions. The biosynthesized AgNPs have been characterized by UV-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biosynthesized AgNPs showed an absorption peak at 423 nm, spherical shape, and an average particle size of 17.43 nm. FTIR shows the bands at 3321.50, 2160.15, and 1636.33 cm-1 corresponding to the binding vibrations of amine, alkyne nitrile, and primary amine bands, respectively. The biosynthesized AgNPs showed antimicrobial activity against a variety of microbial pathogens of medical importance. Using resazurin-based microtiter dilution, the minimum inhibitory concentration (MIC) values for AgNPs were 500 µg/mL for all microbial pathogens except for Klebsiella pneumoniae ATCC13883, which has a higher MIC value of 1000 µg/mL. CONCLUSIONS: The obtained data revealed the successful green production of AgNPs using the supernatant of Leclercia adecarboxylata THHM that can be effectively used as an antimicrobial agent against most human pathogenic microbes.

Reusable kaolin impregnated aminated chitosan composite beads for efficient removal of Congo red dye: isotherms, kinetics and thermodynamics studies.

In this investigation, Kaolin (K) impregnated aminated chitosan (AM-CTS) composite beads were fabricated with multi-features including low-cost, high performance, renewable and ease of separation for adsorption of anionic Congo red (CR) dye. Characterization tools such as FTIR, XRD, SEM, TGA, BET, XPS and Zeta potential were thoroughly employed to confirm the successful formulation process. The results revealed that K@ AM-CTS composite beads displayed higher specific surface area (128.52 m2/g), while the thermal stability was prominently improved compared to pure AM-CTS. In addition, the adsorption equilibrium of CR dye was accomplished rapidly and closely gotten within 45 min. The removal efficiency was significantly enriched and reached 90.7% with increasing kaolin content up to 0.75%, compared to 20.3 and 58% for pristine kaolin and AM-CTS, respectively. Moreover, the adsorption process obeyed the pseudo-first order kinetic model, while data were agreed with the Freundlich isotherm model with a maximum adsorption capacity reached 104 mg/g at pH 6. Furthermore, D-R isotherm model demonstrated the physical adsorption process of CR dye, which includes the electrostatic interactions, ion exchange and H-bonding. Thermodynamics evidenced the spontaneous and endothermic nature of the adsorption process. Interestingly, the developed K@AM-CTS composites beads showed better reusability for eight consecutive cycles, suggesting their feasible applicability for adsorptive removal anionic dyes from polluted aquatic bodies.

The green exfoliation of graphite waste and its suitability for biosensor applications.

This work is concerned with the bio-exfoliation of graphite using a soil bacterium. The isolated bacterium showed a detectable ability to oxidize and change its physical appearance and chemical structure. Multiple characterization procedures were used to study the physical and chemical changes. Raman and FTIR spectroscopy proved that the isolate G3 partially exfoliated the graphite into multi-layer sp2 graphitic layers. Scanning electron microscopy (SEM) proved that there was a change in morphology between untreated graphite waste and that manipulated by bacteria. Cyclic voltammetry results proved that the green exfoliated graphite (GEG) was suitable for use in biosensor applications and showed a noticeable ability to detect methanol, even at lower concentrations. These findings are considered as promising for the biological manipulation of graphite waste for environmental purposes. In addition, it is proved that the bacterial transformation of graphite into other GEG structures occurs without needing the chemically hazardous methods that are currently applied.

Tested functionalization of alginate-immobilized ureolytic bacteria for improvement of soil biocementation and maximizing water retention.

The future expected water scarcity in the world invites the scientists to figure out sustainable solutions for agriculture needs. One of suggested solutions could be the improvement of soil stability and increasing its water retention ability. The current proposal is concerning by the improvement of soil stability through biocementation process. While, water retention ability was enhanced through the amendment of tested soils with alginate hydrogel. An ureolytic bacterial isolate showed a detectable ability to dissociate urea and act as a nucleation site for calcium carbonate precipitation. The bacterium was identified as Bacillus sp. after comparing with other strains in GenBank. The mechanical properties of three tested soil types (sand, calcareous, and clay) were improved after the biocementation by calcium carbonate from 119.8, 45.9, and 5 (N) to 187.5, 423.9, and 337.2, respectively. The Energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the appearance of carbon element in samples containing bacterial-immobilized beads and free bacterial cells indicating calcium carbonate formation. The water uptake measurements investigated the ability of alginate beads to retain water with a percentage of 55%. The overall results prove the capability of Bacillus sp. strain combined with alginate hydrogel to improve the soil stability and water retention ability.

Hydroxyethyl cellulose hydrogel for wound dressing: Fabrication, characterization and in vitro evaluation.

In this study, new hydrogel membranes were developed based on hydroxyethyl cellulose (HEC) supplemented with tungsten oxide for further implementing in wound treatment. HEC hydrogel membranes were fabricated and crosslinked using citric acid (CA). Various tests were carried out including FTIR, XRD, porosity measurements, swelling, mechanical properties, gel fraction, and thermal gravimetric analysis to evaluate the efficiency of the prepared membranes as wound dressing material. In addition, wound healing activity of the examined membranes for human dermal fibroblast cell line was investigated employing in vitro scratching model. Furthermore, the potency of the prepared membranes to suppress wound complications was studied via determination of their anti-inflammatory and antibacterial activities exploiting MTT, ELISA, and disk agar diffusion methods. The results demonstrated that the HEC hydrogel membranes revealed an anti-inflammatory and antibacterial efficacy. Moreover, HEC improved the safety of tungsten oxide toward normal human cells (white blood cells and dermal fibroblast). Furthermore, HEC membranes loaded with WO3 revealed the highest activities against Salmonella sp. pursued by P. aeruginosa in compared with the negative HEC hydrogel membrane. The current approach corroborated that HEC amended by tungsten oxide could be applied as a promising safe candidate for wound dressing material.