Eco-friendly decoration of graphene oxide with green synthesized silver nanoparticles: cytotoxic activity

Phytotoxicity and Antimicrobial Activity of Green Synthesized Silver Nanoparticles Using Nigella sativa Seeds on Wheat Seedlings

Recently, the green synthesis of nanomaterials has grown in popularity and has become one of the most used approaches. Plant extracts are safe for the environment and could be cost-effective for nanoparticle preparation. Silver nanoparticles (AgNPs) have been synthesized using aqueous extracts of Nigella sativa (N. sativa) seeds. The formation of AgNPs was confirmed by using an X-ray diffractometer, a UV-visible spectrometer, and a transmission electron microscope. The phytotoxicity and genotoxicity of different AgNP concentrations (12.5, 25, 50, 75, and 100 μg·L−1) were evaluated by wheat (Triticum aestivum L.) seed germination. The results showed that AgNPs did not significantly affect germination, while root and coleoptile lengths decreased considerably. On the contrary, the biomass of seedlings markedly increased in response to AgNP treatments. Moreover, genotoxicity was detected, especially at high concentrations of AgNPs. DNA, RNA, and total soluble proteins of wheat seedlings significantly decreased. In addition, antimicrobial activities of biosynthesized AgNPs were detected.

Green Metallic Nanoparticles for Cancer Therapy: Evaluation Models and Cancer Applications

Metal-based nanoparticles are widely used to deliver bioactive molecules and drugs to improve cancer therapy. Several research works have highlighted the synthesis of gold and silver nanoparticles by green chemistry, using biological entities to minimize the use of solvents and control their physicochemical and biological properties. Recent advances in evaluating the anticancer effect of green biogenic Au and Ag nanoparticles are mainly focused on the use of conventional 2D cell culture and in vivo murine models that allow determination of the half-maximal inhibitory concentration, a critical parameter to move forward clinical trials. However, the interaction between nanoparticles and the tumor microenvironment is not yet fully understood. Therefore, it is necessary to develop more human-like evaluation models or to improve the existing ones for a better understanding of the molecular bases of cancer. This review provides recent advances in biosynthesized Au and Ag nanoparticles for seven of the most common and relevant cancers and their biological assessment. In addition, it provides a general idea of the in silico, in vitro, ex vivo, and in vivo models used for the anticancer evaluation of green biogenic metal-based nanoparticles.

Anti-dyslipidemic properties of green gold nanoparticle: improvement in oxidative antioxidative balance and associated atherogenicity and insulin resistance

Background

Nowadays, the green synthesis of AuNPs in the presence of plants has been attracted a lot of attention. Herein, in vivo antidiabetic activity of AuNPs synthesized using Ziziphus jujuba in streptozotocin-induced diabetic rats has been evaluated.

Methods

Formation of AuNPs was confirmed by UV-vis, HR-TEM and XRD. Different doses of jujube gold nanoparticles (0.5 and 1 mg/kg) were used to treat streptozotocin-induced diabetic rats in different groups. At the end of experiment (21 days), serum level of fasting blood glucose (FBG), insulin, Body weight, HOMA-IR, vitamin D, ALT, AST, urea, creatinine, lipid profile, prooxidant-antioxidant balance (PAB) and liver oxidative stress markers were determined.

Results

results showed a significant decrease in the level of liver MDA (P = 0.001), fasting blood glucose (P = 0.0001), HOMA-IR (P = 0.0001), ALT (P = 0.0001), AST (P = 0.0001), urea (P = 0.02), Triglycerides (P = 0.002), Total cholesterol (P = 0.0001), PAB (P = 0.0001) and AIP (P = 0.001) and in contrast a significant increase total antioxidant capacity (P = 0.02), insulin (P = 0.03), Body weight (P = 0.0001) and vitamin D (P = 0.0001) in the AuNPs-treated diabetic group compared to the diabetic rats. No significant change was observed in the total thiol group (P = 0.18), LDL-C (P = 0.43), creatinine (P = 0.09) and HDL-C (P = 0.71) level in diabetic rats treated with AuNPs compared to diabetic rats.

Conclusion

The results of this study proves that green AuNPs exerted promising antidiabetic and anti-oxidant properties.

Advancement of Ag-Graphene Based Nanocomposites: An Overview of Synthesis and Its Applications

Graphene has been employed as an excellent support for metal nanomaterials because of its unique structural and physicochemical properties. Silver nanoparticles (AgNPs) with exceptional properties have received considerable attention in various fields; however, particle aggregation limits its application. Therefore, the combination of AgNPs and graphene based nanocomposites (Ag-graphene based nanocomposites) has been widely explored to improve their properties and applications. Excitingly, enhanced antimicrobial, catalytic, and surface enhanced Raman scattering properties are obtained after their combination. In order to have a comprehensive knowledge of these nanocomposites, this Review highlights the chemical and biological synthesis of Ag-graphene nanocomposites. In particular, their applications as antimicrobial agents, catalysts, and sensors in biomedicine, agricultural protection, and environmental remediation and detection are covered. Meanwhile, the factors that influence the synthesis and applications are also briefly discussed. Furthermore, several important issues on the challenges and new directions are also provided for further development of these nanocomposites.

A review on biosynthesis of silver nanoparticles and their biocidal properties

Use of silver and silver salts is as old as human civilization but the fabrication of silver nanoparticles (Ag NPs) has only recently been recognized. They have been specifically used in agriculture and medicine as antibacterial, antifungal and antioxidants. It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus Candida albicans by binding Ag/Ag+ with the biomolecules present in the microbial cells. It has been suggested that Ag NPs produce reactive oxygen species and free radicals which cause apoptosis leading to cell death preventing their replication. Since Ag NPs are smaller than the microorganisms, they diffuse into cell and rupture the cell wall which has been shown from SEM and TEM images of the suspension containing nanoparticles and pathogens. It has also been shown that smaller nanoparticles are more toxic than the bigger ones. Ag NPs are also used in packaging to prevent damage of food products by pathogens. The toxicity of Ag NPs is dependent on the size, concentration, pH of the medium and exposure time to pathogens.