Capping agents are of utmost importance as stabilizers that inhibit the over-growth of nanoparticles and prevent their aggregation/coagulation in colloidal synthesis. The capping ligands stabilize the interface where nanoparticles interact with their medium of preparation. Specific structural features of nanoparticles are attributed to capping on their surface. These stabilizing agents play a key role in altering the biological activities and environmental perspective. Stearic effects of capping agents adsorbed on the surface of nanoparticles are responsible for such changing physico-chemical and biological characteristics. Firstly, this novel review article introduces few frequently used capping agents in the fabrication of nanoparticles. Next, recent advancements in biomedicine and environmental remediation approaches of capped nanoparticles have been elaborated. Lastly, future directions of the huge impact of capping agents on the biological environment have been summarized.

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Role of capping agents in the application of nanoparticles in biomedicine and environmental remediation: recent trends and future prospects

Green synthesis of ZnO nanoparticles using Tecoma castanifolia leaf extract: Characterization and evaluation of its antioxidant, bactericidal and anticancer activities

Photocatalytic water decontamination using graphene and ZnO coupled photocatalysts: A review

Plants are one of the best sources to obtain a variety of natural surfactants in the field of green synthesizing material. Sambucus ebulus, which has unique natural properties, has been considered a promising material in traditional Asian medicine. In this context, zinc oxide nanoparticles (ZnO NPs) were prepared using S. ebulus leaf extract, and their physicochemical properties were investigated. X-ray diffraction (XRD) results revealed that the prepared ZnO NPs are highly crystalline, having a wurtzite crystal structure. The average crystallite size of prepared NPs was around 17 nm. Green synthesized NPs showed excellent absorption in the UV region as well as strong yellow-orange emission at room temperature. Prepared nanoparticles exhibited good antibacterial activity against various organisms and a passable photocatalytic degradation of methylene blue dye pollutants. The obtained results demonstrated that the biosynthesized ZnO NPs reveal interesting characteristics for various potential applications in the future.

https://www.mdpi.com/2076-3417/10/10/3620/pdf

Preparation and Characterization of Zinc Oxide Nanoparticles Using Leaf Extract of Sambucus ebulus

One of the promising ways to overcome microbial antibiotic resistance is the use of nanoparticles of metal oxides. As you know, a wide range of metals has antimicrobial action: Ag, Al, Cu, Fe, Mo, Mn, etc. The mechanisms of the antimicrobial action of metals are impaired functioning of microbial enzymes, generation of reactive oxygen species, damage to the cell membrane, and genotoxic action. ZnO nanoparticles have bacteriostatic and bactericidal action against gram-positive and gram-negative bacteria, as well as fungicidal activity. The mechanism of action is based on the release of Zn2+, generation of reactive oxygen species, damage to the cell membrane, binding to microbial proteins and nucleic acids. NPs based on ZnO have a number of advantages: high antibacterial efficiency at low concentrations (0.16-5.00 mM/l), action on a wide range of microbial strains, and relatively low production costs. Methods have now been found to improve the antimicrobial properties of nanoparticles. The use of several methods at the same time in some cases gives a synergistic effect. All of the above allows us to predict the use of ZnO nanoparticles as a new generation of antimicrobial agents in the near future.

/pdf/a-mini-review-of-antibacterial-properties-of-zno-1aty9exf12.pdf

A Mini Review of Antibacterial Properties of ZnO Nanoparticles

The novelty of this present work is the investigation of the anti-bacterial, anti-arthritic, anti-oxidant and in vitro cytotoxicity activities of green synthesized Zinc Oxide Nanoparticles (ZnO NPs) using leaf aqueous extract of Tectona grandis (L.). Zinc nitrate acts as the precursor and the leaf extract acts as the reducing agent. The synthesized ZnO NPs are characterized by powder X-ray diffraction (PXRD) analysis and the crystalline size is calculated by the Scherrer formula. FTIR analysis confirms the presence of various functional groups in the leaf extract as well as in the NPs. The UV absorption peak is observed at 360 nm and the calculated energy band gap is found to be 3.4 eV. Dynamic Light Scattering (DLS) analysis shows the stability and particle size of the synthesized ZnO NPs. The crystalline size, shape and surface morphology of the ZnO NPs are determined by using Field Emission Scanning Electron Microscopy (FE-SEM). Green synthesized ZnO NPs exhibited interesting antibacterial activity against Gram-positive and Gram-negative bacteria and exerted excellent DPPH (di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium) free radical scavenging activity. They also showed maximum inhibition of protein denaturation (90.46 ± 0.02) and proteinase inhibitory activity (87.68 ± 0.03) at a dose of 200 μg ml−1 respectively. The anticancer activity of ZnO NPs was also tested against normal and cancer osteoblast MC3t3-E1 cell lines and found a reduction in the size of cancer cells.

Synthesis of ZnO nanoparticles using leaf extract of Tectona grandis (L.) and their anti-bacterial, anti-arthritic, anti-oxidant and in vitro cytotoxicity activities

D. Soni

Papers

Synthesis of ZnO nanoparticles using leaf extract of Tectona grandis (L.) and their anti-bacterial, anti-arthritic, anti-oxidant and in vitro cytotoxicity activities