Search Results (9)

Multidrug-resistant bacterial pathogens pose a critical global health challenge, necessitating safe and effective antimicrobial alternatives. Plant-derived nanoparticles represent promising candidates due to their bioactivity and biocompatibility. Magnesium nitrate nanoparticles were synthesized using Momordica charantia peel extract through green chemistry. Phytochemical screening identified flavonoids, phenolics, tannins, and terpenoids that facilitated nanoparticle formation and stability. Characterization via scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy confirmed polydisperse size distribution (1–100 nm), crystalline structure, and functional group capping. Disc diffusion assays demonstrated concentration-dependent antibacterial activity against multidrug-resistant strains, with maximum inhibition zones of 17.6 ± 1.1 mm against Gram-positive bacteria. Minimum inhibitory concentration and minimum bactericidal concentration assays revealed high bactericidal activity, particularly against Gram-positive bacteria. Time-kill kinetic studies showed concentration- and time-dependent killing with ≥3 log₁₀ reduction in viable bacterial counts at higher concentrations. Nanoparticle–antibiotic combinations exhibited markedly enhanced activity against multidrug-resistant strains compared to free antibiotics, indicating synergistic effects. Toxicity assessment using Brine Shrimp Lethality Assay revealed low toxicity (LC₅₀ > 1000 µg/mL). Green-synthesized magnesium nitrate nanoparticles demonstrate potent antibacterial properties and effectively enhance antibiotic potency against multidrug-resistant bacteria. Further studies are required to validate therapeutic applicability. Full article

Magnesium oxide (MgO) nanoparticles, recognized for their versatile applications from catalysis to biomedicine, require synthesis methods that offer precise control over their properties while ensuring safety and scalability. This study explores a safer, industrially viable adaptation of the polyacrylamide gel synthesis route by utilizing magnesium sulfate (MgSO₄) instead of conventional nitrates to mitigate explosion risks during calcination. A systematic study was conducted to evaluate the influence of key synthesis parameters, such as crosslinker ratio, initiator concentration, precursor loading, calcination conditions (including temperature, time, and heating rate), pH, and the use of chelating agents (EDTA and citric acid), on the purity, morphology, size distribution, and colloidal stability of the synthesized MgO nanoparticles. Characterization via X-ray spectroscopy XRF and XRD, acoustic spectroscopy, nitrogen physisorption (BET), electronic microscopy SEM and TEM and dispersion stability analysis revealed that polymeric cell volume (controlled by crosslinker and initiator) significantly influences size distribution, while chelating agents in alkaline environments drastically reduce particle size to ~20 nm and alter morphology to platelets (EDTA) or polygonal shapes (citric acid). Crucially, a low heating rate (2.5 °C/min) was found to yield smaller particles (~30 nm) and higher purity. This work provides a comprehensive blueprint for the tailored, safe, and scalable synthesis of MgO nanoparticles with targeted properties for specific technological applications. Full article

This work reports the biosynthesis of silver nanoparticles (AgNPs) using an autoclave method with Tagetes erecta extract (TEE) as a source of reducing agents, silver nitrate (AgNO₃) as the metal precursor, and a nucleating agent (i.e., sodium chloride [S]) or a structure director agent (i.e., gum Arabic [G] or hydrous magnesium silicate/talc powder [T]) to tailor the morphology of AgNPs. Since the properties and potential applications of AgNPs depend on their size and shape, these additives were employed to achieve morphological control. Phytochemical screening tests and UPCL-Qtof-MS/MS profiling of TEE were performed to identify the compounds present in the extract, indicating that highly polar phenolic compounds such as saponins, tannins, and flavonoids are present in TEE, allowing it to act as a source of reducing/stabilizing agents. The biosynthesized AgNPs exhibited different morphologies (i.e., spheres, rods, ribbons, and wires) depending on the modifying agent used (i.e., S, G, or T). Characterization techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), and X-ray diffraction (XRD) confirmed the successful use of S, G, and T in modulating AgNP morphology. The results of the antibacterial activity evaluation demonstrated that both TEE and AgNPs possess bacteriostatic activity against Escherichia coli and Enterococcus faecalis, with the use of S as a nucleating agent increasing the inhibitory effect of AgNPs. Full article

The application of foliar sprays of suspensions of relatively insoluble essential element salts is gradually becoming common, chiefly with the introduction of nano-technology approaches in agriculture. However, there is controversy about the effectiveness of such sparingly soluble nutrient sources as foliar fertilizers. In this work, we focussed on analysing the effect of adding Ca-carbonate (calcite, CaCO₃) micro- and nano-particles as model sparingly soluble mineral compounds to foliar fertilizer formulations in terms of increasing the rate of foliar absorption. For these purposes, we carried out short-term foliar application experiments by treating leaves of species with variable surface features and wettability rates. The leaf absorption efficacy of foliar formulations containing a surfactant and model soluble nutrient sources, namely Ca-chloride (CaCl₂), magnesium sulphate (MgSO₄), potassium nitrate (KNO₃), or zinc sulphate (ZnSO₄), was evaluated alone or after addition of calcite particles. In general, the combination of the Ca-carbonate particles with an essential element salt had a synergistic effect and improved the absorption of Ca and the nutrient element provided. In light of the positive effects of using calcite particles as foliar formulation adjuvants, dolomite nano- and micro-particles were also tested as foliar formulation additives, and the results were also positive in terms of increasing foliar uptake. The observed nutrient element foliar absorption efficacy can be partially explained by geochemical modelling, which enabled us to predict how these formulations will perform at least in chemical terms. Our results show the major potential of adding mineral particles as foliar formulation additives, but the associated mechanisms of action and possible additional benefits to plants should be characterised in future investigations. Full article

The magnesium nanosized ferrite powder with formula MgFe₂O₄ was synthesized via a pyrochemical sol–gel glycine–nitrate method and annealed consistently at temperatures of up to 1300 °C. The MgFe₂O₄ ferrite samples’ microstructure was studied by SEM and XRD methods. According to the results of the studies, the increase in MgFe₂O₄ nanoparticles size from about 15 nm to micron-sized particles was observed when increasing annealing temperatures. The DC electrical conductivity of MgFe₂O₄ also clearly shows the change in conduction behavior of samples with increased calcination temperatures. The electromagnetic microwave properties of micron-sized particles of MgFe₂O₄ ferrite powder for a 1200 °C annealing temperature were studied for composites in paraffin matrix with produced magnetic filler mass concentration at 40% and 50%. The filament composites of polymer polylactic acid with MgFe₂O₄ ferrite powder samples were prepared by the FDM 3D-printing process and their microwave-absorbing properties were investigated. The application of developed PLA–MgFe₂O₄ ferrite filament for fabricating magnetic microwave-absorbing components also was demonstrated. Full article

Nitrate is a widespread water contaminant that can pose environmental and health risks. Various conventional techniques can be applied for the removal of nitrate from water and wastewater, such as biological denitrification, ion exchange, nanofiltration, and reverse osmosis. Compared to traditional methods, the chemical denitrification through zero-valent metals offers various advantages, such as lower costs, simplicity of management, and high efficiencies. The most utilized material for chemical denitrification is zero-valent iron (ZVI). Aluminium (ZVA), magnesium (ZVM), copper (ZVC), and zinc (ZVZ) are alternative zero-valent metals that are studied for the removal of nitrate from water as well as from aqueous solutions. To the best of our knowledge, a comprehensive work on the use of the various zero-valent materials that are employed for the removal of nitrate is still missing. Therefore, in the present review, the most recent papers concerning the use of zero-valent materials for chemical denitrification were analysed. The studies that dealt with zero-valent iron were discussed by considering microscopic (mZVI) and nanoscopic (nZVI) forms. For each Fe⁰ form, the effects of the initial pH, the presence or absence of dissolved oxygen, the initial nitrate concentration, the temperature, and the dissolved ions on the nitrate removal process were separately evaluated. Finally, the different materials that were employed as support for the nanoparticles were examined. For the other zero-valent metals tested, a detailed description of the works present in the literature was carried out. A comparison of the various features that are related to each considered material was also made. Full article

Recently, large-scale agriculture has led to increasing crop production. To increase crop productivity in large-scale cropping systems, attempts have been made to make nano-fertilizers and deliver them to the crops by extension of nanotechnology. Hence, nano-fertilizers might be defined as nanoparticles that may directly assist in supplying essential nutrients for crop productivity. Seed germination is the first and the most susceptible stage in the plant’s growing phases, so could be considered as an index to evaluate the effect of newly developed materials such as nanoparticles (NPs), providing useful information for researchers. In our experiments, germination tests have been carried out in Petri dishes containing wet filter paper and nano-primed seeds. We had biosynthesized seven nanoparticles in our previous studies including calcinated and non-calcinated zinc oxide, zinc, magnesium oxide, silver, copper, and iron nanoparticles. The effect of these biogenic nanoparticles and their counterpart metallic salts including zinc acetate, magnesium sulfate, silver nitrate, copper sulfate, and iron (III) chloride was studied on two popularly grown plants, wheat and flax, in laboratory conditions to obtain preliminary information for future field experiments. Germination percentage, shoot length, root length, seedlings length, root–shoot ratio, seedling vigor index (SVI), shoot length stress tolerance index (SLSI), and root length stress tolerance index (RLSI) were calculated on the second and seventh days of the experiment. According to the results, the response of the plants to metal containing nanoparticles and metal salts mainly depend on the type of the metal, plant species, concentration of the NP suspension or salt solution, condition of the exposure, and the stage of growth. Full article

To develop a method for the preparation of MgO nanoparticles, precatalyst synthesis from magnesium nitrate with ammonia and calcination was performed in presence of PEG in air. Without PEG, the catalysts are inactive. The conversion to hydroxide was performed using a PEG/MgO molar ratio of 1, but, before the calcination, excess of PEG was either saved (PEG1) or increased to 2, 3, or 4 (PEG 2–4). Catalysts were calcined at 400–660 °C and characterized using XRD, N₂ adsorption-desorption, TGA, FTIR, and SEM. The FAME yield in the reactions with methanol depend on the PEG ratio used and the calcination temperature. The optimal calcination temperature and highest FAME yield in the 6 h reactions for catalysts PEG1, PEG2, PEG3 and PEG4 were 400 °C, 74%; 500 °C, 80%; 500 °C, 51% and 550 °C, 31%, respectively. The yield dependence on calcination temperature for catalysts with a constant PEG ratio is similar to that of a bell curve, which becomes wider and flatters with an increase in PEG ratio. For most catalysts, the FAME yield increases as the size of the crystallites decreases. The dependence of FAME and the intermediate yield on oil conversion confirms that all catalysts have strong base sites. Full article

The use of nanoparticles in fertilisation has confirmed positive effects on plant growth and yield. Simultaneously, there is still little research into the effects of nanoparticles on the antioxidant system of plants. Due to the positive effect of nano zinc oxide on plants and the special property of nano zero-valent iron, these particles were selected for the research. The nano zero-valent iron is crucial for plants as it is present in agglomerations on the surface of roots where it increases the absorptive surface of the rhizosphere and causes elongation of the roots. The study aims to determine the influence of selected nanoparticles as a potential improvement for conventional fertilisation by magnesium (Mg), calcium (Ca), phosphorus (P) and nitrogen (N). After the cultivation, the influence of nanoparticles on the accumulation of macronutrients in plant tissues, biometric parameters, and physiological response (chlorophyll and antioxidant system) of radish (Raphanus sativus) were assessed. The solution used in this study helped to increase the content of nitrates (V) in radish roots by 31.7–73.2% compared to conventional fertilisation. Nevertheless, nanoparticles supplementation resulted in a decrease in the concentrations of magnesium, iron (Fe) and zinc (Zn) in plants. The high dose of used fertilisers increased the thickness and length of tubers by approximately 50.0%, compared to the control samples. The “Macro 2 + nano” variant caused an increase of plant biomass up to 70.0%. The analysis of the antioxidant system showed that the application of macronutrients with nanoparticles increased the concentration of polyphenols in plant tubers by 46.0–55.6%. Interestingly, while implemented conditions caused a 1.5-fold increase in CAT activity in leaves, at the same time the decrease in CAT activity in plant roots was observed. Based on the obtained results of the enzymatic antioxidant system and biometric parameters of plants, it can be concluded that (in laboratory conditions) nZVI and nanoZnO are efficient components of fertilisers. However, the effects on other organisms must be investigated before implementing a method for widespread use. Full article