Plant-Mediated Synthesis of Magnetite Nanoparticles with Matricaria chamomilla Aqueous Extract

Magnetite nanoparticles (NPs) possess properties that make them suitable for a wide range of applications. In recent years, interest in the synthesis of magnetite NPs and their surface functionalization has increased significantly, especially regarding their application in biomedicine such as for controlled and targeted drug delivery. There are several conventional methods for preparing magnetite NPs, all of which mostly utilize Fe(iii) and Fe(ii) salt precursors. In this study, we present a microwave hydrothermal synthesis for the precipitation of magnetite NPs at temperatures of 200 °C for 20 min and 260 °C for 5 min, with only iron(iii) as a precursor utilizing chamomile flower extract as a stabilizing, capping, and reducing agent. Products were characterized using FTIR, PXRD, SEM, and magnetometry. Our analysis revealed significant differences in the properties of magnetite NPs prepared with this approach, and the conventional two-precursor hydrothermal microwave method (sample MagH). FTIR and PXRD analyses confirmed coated magnetite particles. The temperature and magnetic-field dependence of magnetization indicate their superparamagnetic behavior. Importantly, the results of our study show the noticeable cytotoxicity of coated magnetite NPs-toxic to carcinoma cells but harmless to healthy cells-further emphasizing the potential of these NPs for biomedical applications.

Antioxidant and hypoglycemic potential of phytogenic cerium oxide nanoparticles

Plants provide humans with more than just food and shelter; they are also a major source of medications. The purpose of this research was to investigate the antioxidant and hypoglycemic potential of green synthesized CeONPs using Mentha royleana leaves extract. The morphological and physicochemical features of CeONPs were evaluated by UV-Visible spectrophotometry, Scanning Electron Microscopy, Energy Dispersive X-rays and Fourier-transform infrared spectrometry, Dynamic light scattering, Atomic Force Microscopy, Zeta Potential. The average size range of synthesized CeONPs diameter between 46 and 56 nm, crystalline in shape, with Polydispersity index value of 0.2 and subatomic particles mean diameter was 4.5-9.1 nm. The antioxidant capability of CeONPs was assessed using DPPH, ABTS⁺, hydrogen peroxide, hydroxyl radical scavenging, and reducing power tests. The hypoglycemic potential of CeONPs was investigated using alpha-amylase, alpha-glucosidase, glucose absorption by yeast cells, and antisucrase. The effective concentrations were 500 and 1000 µg/ml found good in suppressing radical species. To explore the hypoglycemic potential of CeONPs, alpha-amylase, alpha-glucosidase, glucose absorption by yeast cell, and antisucrase assays were performed. Glucose absorb by yeast cells assay was tested for three distinct glucose concentrations: 5 mmol/L, 10 mmol/L, and 25 mmol/L. Green synthesize CeONPs showed a dose-dependent response, higher concentrations of CeONPs imposed a stronger inhibitory impact on the catalytic site of enzymes. This study suggest that CeONPs could possibly binds to the charge carrying species and act as competitive inhibitor which slow down the enzyme substrate reaction and prevents enzymatic degradation. The study's findings were outstanding, which bodes well for future medicinal applications of CeONPs.

Sustainable synthesis of microwave-assisted IONPs using Spinacia oleracea L. for control of fungal wilt by modulating the defense system in tomato plants

BACKGROUND

Changing climate enhances the survival of pests and pathogens, which eventually affects crop yield and reduces its economic value. Novel approaches should be employed to ensure sustainable food security. Nano-based agri-chemicals provide a distinctive mechanism to increase productivity and manage phytopathogens, with minimal environmental distress. In vitro and in greenhouse studies were conducted to evaluate the potential of green-synthesized iron-oxide nanoparticles (IONPs) in suppressing wilt infection caused by Fusarium oxysporum f. sp. lycospersici, and improving tomato growth (Solanum lycopersicum) and fruit quality.

RESULTS

Various microwave powers (100-1000 W) were used to modulate the properties of the green-synthesized IONPs, using spinach as a starting material. The IONPs stabilized with black coffee extract were substantively characterized using X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy, dielectric and impedance spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy (SEM and TEM, respectively), and magnetization analysis. XRD revealed a cubic magnetite (Fe3O4) phase with super-paramagnetic nature, detected at all microwave powers. The binding energies of Fe 2p3/2 (710.9 eV) and Fe 2p1/2 (724.5 eV) of Fe3O4 NPs were confirmed using XPS analysis at a microwave power of 1000 W. Uniform, spherical/cubical-shaped particles with an average diameter of 4 nm were confirmed using SEM and TEM analysis. A significant reduction in mycelial growth and spore germination was observed upon exposure to different IONP treatments. Malformed mycelium, DNA fragmentation, alternation in the cell membrane, and ROS production in F. oxysporum indicated the anti-microbial potential of the IONPs. The particles were applied both through the root (before transplantation) and by means of foliar application (after two weeks) to the infected seedlings. IONPs significantly reduced disease severity by an average of 47.8%, resulting in increased plant growth variables after exposure to 12.5 µg/mL of IONPs. Analysis of photosynthetic pigments, phenolic compounds, and anti-oxidant enzymes in the roots and shoots showed an increasing trend after exposure to various concentrations of IONPs. Correspondingly, lycopene, vitamin C, total flavonoids, and protein content were substantially improved in tomato fruits after treatment with IONPs.

CONCLUSION

The findings of the current investigation suggested that the synthesized IONPs display anti-fungal and nutritional properties that can help to manage Fusarium wilt disease, resulting in enhanced plant growth and fruit quality.

Rapid and Green Preparation of Multi-Branched Gold Nanoparticles Using Surfactant-Free, Combined Ultrasound-Assisted Method

The conventional seed-mediated preparation of multi-branched gold nanoparticles uses either cetyltrimethylammonium bromide or sodium dodecyl sulfate. However, both surfactants are toxic to cells so they have to be removed before the multi-branched gold nanoparticles can be used in biomedical applications. This study describes a green and facile method for the preparation of multi-branched gold nanoparticles using hydroquinone as a reducing agent and chitosan as a stabilizer, through ultrasound irradiation to improve the multi-branched shape and stability. The influence of pH, mass concentration of chitosan, hydroquinone concentration, as well as sonication conditions such as amplitude and time of US on the growth of multi-branched gold nanoparticles, were also investigated. The spectra showed a broad band from 500 to over 1100 nm, an indication of the effects of both aggregation and contribution of multi-branches to the surface plasmon resonance signal. Transmission electron microscopy measurements of GNS under optimum conditions showed an average core diameter of 64.85 ± 6.79 nm and 76.11 ± 14.23 nm of the branches of multi-branched particles. Fourier Transfer Infrared Spectroscopy was employed to characterize the interaction between colloidal gold nanoparticles and chitosan, and the results showed the presence of the latter on the surface of the GNS. The cytotoxicity of chitosan capped GNS was tested on normal rat fibroblast NIH/3T3 and normal human fibroblast BJ-5ta using MTT assay concentrations from 50–125 µg/mL, with no adverse effect on cell viability.