The current work concentrated on the green synthesis of silver nanoparticles (AgNPs) through the use of aqueous Citruslimon zest extract, optimizing the different experimental factors required for the formation and stability of AgNPs. The preparation of nanoparticles was confirmed by the observation of the color change of the mixture of silver nitrate, after the addition of the plant extract, from yellow to a reddish-brown colloidal suspension and was established by detecting the surface plasmon resonance band at 535.5 nm, utilizing UV-Visible analysis. The optimum conditions were found to be 1 mM of silver nitrate concentration, a 1:9 ratio extract of the mixture, and a 4 h incubation period. Fourier transform infrared spectroscopy spectrum indicated that the phytochemicals compounds present in Citrus limon zest extract had a fundamental effect on the production of AgNPs as a bio-reducing agent. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential (ZP), dynamic light scattering (DLS), SEM, EDX, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis, which showed crystalline spherical silver nanoparticles. In addition, the antimicrobial and antioxidant properties of this bioactive silver nanoparticle were also investigated. The AgNPs showed excellent antibacterial activity against one Gram-negative pathogens bacteria, Escherichia coli, and one Gram-positive bacteria, Staphylococcus aureus, as well as antifungal activity against Candida albicans. The obtained results indicate that the antioxidant activity of this nanoparticle is significant. This bioactive silver nanoparticle can be used in biomedical and pharmacological fields.

Hesperidin is a flavonoid glycoside with proven therapeutic activities for various diseases, including cancer. However, its poor solubility and bioavailability render it only slightly absorbed, requiring a delivery system to reach its therapeutic target. Hesperidin loaded on gold nanoparticles (Hsp-AuNPs) was prepared by a chemical synthesis method. Various characterization techniques such as UV-VIS spectroscopy, FTIR, XRD, FESEM, TEM and EDX, Zeta potential analysis, particle size analysis, were used to confirm the synthesis of Hsp-AuNPs. The cytotoxic effect of Hsp-AuNPs on human breast cancer cell line (MDA-MB-231) was assessed using MTT and crystal violet assays. The results revealed significant decrease in proliferation and inhibition of growth of the treated cells when compared with human normal breast epithelial cell line (HBL-100). Determination of apoptosis by fluorescence microscope was also performed using acridine orange-propidium iodide dual staining assay. The in vivo study was designed to evaluate the toxicity of Hsp-AuNPs in mice. The levels of hepatic and kidney functionality markers were assessed. No significant statistical differences were found for the tested indicators. Histological images of liver, spleen, lung and kidney showed no apparent damages and histopathological abnormalities after treatment with Hsp-AuNPs. Hsp-AuNPs ameliorated the functional activity of macrophages against Ehrlich ascites tumor cells-bearing mice. The production of the pro-inflammatory cytokines was also assessed in bone marrow–derived macrophage cells treated with Hsp-AuNPs. The results obviously demonstrated that Hsp-AuNPs treatment significantly inhibited the secretion of IL-1β, IL-6 and TNF.

To synthesize silver nanopaticles from leaves extract of Eucalyptus chapmaniana (E. chapmaniana) and test the antimicrobial of the nanoparticles against different pathogenic bacteria, yeast and its toxicity against human acute promyelocytic leukemia (HL-60) cell line. Ten milliliter of leaves extract was mixed with 90 mL of 0.01 mmol/mL or 0.02 mmol/mL aqueous AgNO3 and exposed to sun light for 1 h. A change from yellowish to reddish brown color was observed. Characterization using UV-vis spectrophotometery and X-ray diffraction analysis were performed. Antimicrobial activity against six microorganisms was tested using well diffusion method and cytoxicity test using 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a yellow tetrazole was obtained on the human leukemia cell line (HL-60). UV-vis spectral analysis showed silver surface plasmon resonance band at 413 nm. X-ray diffraction showed that the particles were crystalline in nature with face centered cubic structure of the bulk silver with broad beaks at 38.50° and 44.76°. The synthesized silver nanoparticles efficiently inhibited various pathogenic organisms and reduced viability of the HL-60 cells in a dose-dependent manner. It has been demonstrated that the extract of E. chapmaniana leaves are capable of producing silver nanoparticles extracellularly and the Ag nanoparticles are quite stable in solution. Further studies are needed to fully characterize the toxicity and the mechanisms involved with the antimicrobial and anticancer activity of these particles.

Bioactive plant chemicals are considered to be rich and useful for creating nanomaterials. The current work investigated the biosynthesis of silver nanoparticles (AgNPs) using ethanolic flaxseed extract as an efficient reducing factor. The production of AgNPs was verified by color-shifting observation of the mixture of silver nitrate (AgNO₃) from yellow to a reddish suspension after the addition of the extract and by evaluating it by UV–visible inspection. Additionally, FTIR spectrum was used to support the identification of functional groups. The morphology and structure of AgNPs were assessed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) examinations, which revealed spherical AgNPs with a diameter of 46.98 ± 12.45 nm and a crystalline structure. The zeta potential (ZP) and dynamic light scattering (DLS) measurements of AgNPs revealed values of −44.5 mV and 231.8 nm, respectively, suggesting appropriate physical stability. The antibacterial activity of AgNPs was investigated against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes, while the antioxidant effect was investigated using the DPPH technique. These obtained AgNPs could potentially be used as efficient antibacterial and antioxidant nanomaterials.

Laser ablation in liquid was utilized to prepare a TiO₂ NP suspension in in deionized distilled water using Q-switch Nd: YAG laser at various laser energies and ablation times. The samples were characterized using UV–visible absorption spectra obtained with a UV–visible spectrophotometer (UV-Vis,) Fourier transform infrared (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM). While, UV-Vis spectra showed the characteristic band-to-band absorption peak of TiO₂ NPs in the UV range. FTIR analysis showed the existence of O-Ti-O bond. XRD patterns indicated the presence of (101) and (112) plane crystalline phases of TiO₂. TEM images showed a spherical-like structure of TiO₂ NPs with various size distributions depending on the ablation period. It was also found that there is a relationship between laser ablation time and TiO₂ NP size distribution, where longer ablation times led to the smaller size distribution. The antibacterial activity of TiO₂ NPs was evaluated with different species of bacteria such as Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, and Staphylococcus aureus, using the liquid approach. The optimum activity of TiO₂ NPs is found to be against E. coli at 1000 μg mL⁻¹. Furthermore, adding, TiO₂ NPs (1000 μg mL⁻¹) in the presence of amoxicillin has a synergic effect on E. coli and S. aureus growth, as measured by the well diffusion method. However, both E. coli (11.6 ± 0.57mm) and S. aureus (13.3 ± 0.57mm) were inhibited by this process.