Impact of the capping agent removal from Au NPs@MOF core-shell nanoparticles heterogeneous catalysts

Metal nanoparticles encased in a MOF shell have shown remarkable properties in catalysis due to potential synergistic effects. However, capping agents, commonly used to prepare these nanoparticles, lower their reactivity...

Synergic effect of aqueous extracts of Ocimum sanctum and Trigonella foenum-graecum L on the in situ green synthesis of silver nanoparticles and as a preventative agent against antibiotic-resistant food spoiling organisms

Combining Ocimum sanctum and Trigonella foenum-graecum L leaf water extracts synergistically act as a reducing and capping agent for the synthesis of narrow polydisperse silver nanoparticles with controlled sizes depending on the precursor (AgNO3) concentration.

Nanomaterials for Sustainability: A Review on Green Synthesis of Nanoparticles Using Microorganisms

Nanotechnology has permeated all areas of sciences as one of the most propitious technology with the deployment of nanoparticles in environmental remediation and biomedical fields; their synthesis under greener conditions has been bourgeoned using microorganisms, plants, etc. to decrease the use of toxic chemicals. Synthesis of nanoparticles by exploiting microorganisms has opened up a new prospect at the interface of nanotechnology, chemistry, and biology enabling access via a biocompatible, safe, sustainable, eco-friendly, and reliable route; microorganisms offer crystal growth, stabilization, and prevention of aggregation thus performing a dual role of reducing and capping agent because of the presence of biomolecules such as enzymes, peptides, poly (amino acids), polyhydroxyalkanoate (PHA), and polysaccharides. Herein, the microorganisms-based synthesis of various nanoparticles comprising gold, silver, platinum, palladium, copper, titanium dioxide, zinc oxide, iron oxide, and selenium along with their appliances in waste treatment, biomedicine namely cancer treatment, antibacterial, antimicrobial, antifungal, and antioxidants, are deliberated.

Antibacterial Effect of Biosynthesized Zinc Oxide Nanoparticles against Erwinia amylovora and Induction of Crop Growth

Objectives: Zinc oxide nanoparticles (ZnO-NPs) are widely recognized as one of the most promising types of materials in a wide range of applications, including agriculture. Modern systemic efforts have identified several therapeutically active microalgae-derived compounds, including phenols, flavonoids and others. The antibacterial properties of the phenolic substances were demonstrated. Hence, the present study aims to exhibit the antibacterial activity of the bioactive compound capped silver nanoparticles under in vitro conditions. Methods: Bioactive compound separated by Solid-phase Extraction method. Dispersible Zinc oxide nanoparticles synthesized using the bioactive compound as the major capping agent. Zinc nitrate was used as starting material and its reduction was carried by phenolic components of Spirulina platensis aqueous extract from Zn2+ to ZnO. The synthesized Zinc oxide nanoparticles are characterized by H1 NMR spectroscopy. Conjugated nanoparticles are characterized physically by Scanning Electron Microscopy (SEM) analysis. SEM demonstrated particle sizes in the range 10–15 nm. ZnO nanoparticles demonstrated antibacterial activity against an isolated plant pathogen Erwinia amylovora. Time kill determination assay was done. Findings: Phenols obtained after Solid Phase Extraction. Hence, this was regarded as the maximum quantified bioactive compound of Spirulina platensis. H1 NMR spectroscopy analyses showed the presence of phenolic compounds and alcohols groups of long chain were also detected. In SEM analysis, the mean diameter of spherical Phenols-ZnOPs is less than 15 nm surrounded by the capping agent. In given time periods of 4, 8, 16, and 24 hour cells, concentrations of 1000µg/mL were 42 %, 33 %, 20 %, and 18 %. At 500 µg/mL of extract concentration, Spirulina platensis inhibited 50% bacterial proliferation (IC50) of Erwinia amylovora. A significant inhibitory effect (p<0.0001) was seen against the plant pathogenic strain. Novelty: In addition to their antibacterial activities, biosynthesized ZnO-NPs are thought to show promise efficacy as growth accelerators. The most dangerous bacterial disease of pear and apple trees is fire blight, caused by Erwinia amylovora. Phenolic capped ZnO-NPs have been found to be efficient plant pathogen antagonists.

Synthesis of Fe:Ag nanocomposites and their anti-bacterial activities

The present study reports the synthesis of Fe:Ag composite nanoparticles by green approach, utilizing Urtica dioica leaves extract, as reducing and capping agent for the metal sources. Formation of composite phases found to depend on the salt sources, which provides different ion species in the reaction mixture. The formation of crystalline nanoparticles having cubic structure was confirmed by XRD analysis. Ag rich crystalline nanoparticles were found to disperse in the oxidized Fe matrix by high resolution transmission microscopic studies. XPS analysis revealed the presence of Fe of in 0, +2, and +3 valance states and Ag in Ag+1 and Ag° states. The synthesized nanoparticles were found to show notable antibacterial activity against the gram negative pathogen E. Coli and gram positive pathogen S. aureus.