Photocatalytic and antibacterial properties of phytosynthesized CeO2 NPs using Moringa oleifera peel extract.

Biosynthetic methods are alternative approaches which are much safer than the normal techniques (physical and chemical) used for the methods for synthesis of metal nanoparticles. The benefits are sample as it is economic and environment friendly. Herein present investigation, we have reported a microwave mediated eco-friendly synthetic approach for preparing cerium oxide (CeO2) nanoparticles. Here, we used Moringa oleifera peel as the stabilizing and reducing agent towards synthesize of Ce2O NPs via microwave irradiation. The NPs were further characterized using UV-Vis, FT-IR, XRD and HR-TEM techniques. The FTIR analysis confirmed the phytochemical involvement in NPs stabilization. The crystallinity of CeO2 nanoparticles are well demonstrated through X-ray Diffraction and HR-TEM. The TEM images reveal the spherical shape of the CeO2 NPs having an average size of 45nm. Additionally, these CeO2 NPs were used successfully as a catalyst in the degradation of the dye, crystal violet. Also the antibacterial activity of the synthesized CeO2 NPs was evaluated using Staphylococcus aureus (Gram positive bacteria) and Escherichia coli (Gram negative bacteria). CeO2 NPs showed better activity on E. coli than S. aureus. We have demonstrated an eco-friendly preparation of CeO2 nanoparticles, a good photocatalyst and having better antibacterial properties.

Surendra TV ，Roopan SM 《-》

RSM optimized Moringa oleifera peel extract for green synthesis of M. oleifera capped palladium nanoparticles with antibacterial and hemolytic property.

Palladium nanoparticles (Pd NPs) are the very good catalytic agents in many coupling reactions, also these are very well biological agents against bacteria and fungus. M. oleifera capped Pd NPs were synthesized from microwave assisted methanolic extract of M. oleifera peel. To optimize the extraction process RSM (Response Surface Methodology) was applied. To get a good extraction yield BBD (Box-Behnken Design) was employed. The better optimized conditions for the extraction was found as 400W, 25mL of CH3OH at 65°C for 2min. We observed 61.66mg of extract yield from this method. Eco-friendly M. oleifera capped Pd NPs were synthesized using M. oleifera peel extract and confirmed using the different characterization techniques like UV- Vis spectroscopy, XRD, SEM and HR-TEM analysis. We found the size of the M. oleifera capped Pd NPs nanoparticles as 27±2nm and shape of the particles as spherical through the TEM analysis. M. oleifera capped Pd NPs exhibits good antibacterial activity against S. aureus (Staphylococcus aureus) and E. coli (Escherichia coli) bacterial strains and we found the zone inhibition as 0.6 and 0.7mm. The synthesized M. oleifera capped Pd NPs are screened for hemolytic activity and it proved the M. oleifera capped Pd NPs are non-toxic on RBCs cells.

Surendra TV ，Roopan SM ，Arasu MV ，Al-Dhabi NA ，Rayalu GM ... -  《-》

Eco-friendly preparation of zinc oxide nanoparticles using Tabernaemontana divaricata and its photocatalytic and antimicrobial activity.

The present work reports the green synthesis of Zinc Oxide Nanoparticles (ZnO NPs) using aqueous Tabernaemontana divaricata green leaf extract. ZnO NPs have been characterized by X-ray diffraction (XRD), Ultra Violet-Visible (UV-Vis) studies, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD pattern analysis confirms the presence of pure hexagonal wurtzite crystalline structure of ZnO. The TEM images reveal the formation of spherical shape ZnO NPs with the sizes ranging from 20 to 50 nm. The FT-IR analysis suggests that the obtained ZnO NPs have been stabilized through the interactions of steroids, terpenoids, flavonoids, phenyl propanoids, phenolic acids and enzymes present in the leaf extract. Mechanism for the formation of ZnO NPs using Tabernaemontana divaricata as bioactive compound is proposed. As prepared ZnO NPs reveals antibacterial activity against three bacterial strains, Salmonella paratyphi, Escherichia coli and Staphylococcus aureus. The ZnO NPs shows higher antibacterial activity against S. aureus and E. coli and lesser antibacterial activity against S. paratyphi compared to the standard pharmaceutical formulation. Photocatalytic activity of synthesized ZnO NPs was analyzed for methylene blue (MB) dye degradation with sunlight. Almost complete degradation of dye occurred in 90 min. This nano-ZnO, prepared by eco-friendly method will be much useful for dye removal and bacterial decontamination.

Raja A ，Ashokkumar S ，Pavithra Marthandam R ，Jayachandiran J ，Khatiwada CP ，Kaviyarasu K ，Ganapathi Raman R ，Swaminathan M ... -  《-》

Biosynthesis of iron nanoparticles using Trigonella foenum-graecum seed extract for photocatalytic methyl orange dye degradation and antibacterial applications.

Trigonella foenum-graecum is the source of various biological and chemical constituents with a wide area of applications, especially in the treatment/prevention of diabetes and other chronic diseases such as cancer. Multiple biological and organic moieties in the aqueous or the organic phase of Trigonella foenum-graecum carry soft reduction properties to reduce the metal cations to nanoparticles. In this investigation, the Trigonella foenum-graecum was found in the seed extract for the first time in an aqueous medium. We successfully synthesized zero-valent iron nanoparticles (Fe0) (ZV-Fe NPs) and stabilized these nanoparticles in an aqueous medium. The stabilization mechanism of Fe NPs by Trigonella foenum-graecum in an aqueous extract was investigated. Further, Fe NPs were characterized by UV-visible spectrometry, X-ray diffraction (XRD), thermogravimetric analysis - derivative thermo-gravimetric (TGA/DTG), magnetization, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) images. The size of the nanoparticles, calculated using the Debye-Scherer equation and TEM, was found to be approximately 11 nm with the highest particle distribution number. Fe NPs are very effective for methyl orange dye degradation under UV light following pseudo first-order kinetics, and the rate constant kapp was found to be 0.025 min-1. Furthermore, Fe NPs were applied to check the antibacterial activities with microorganisms such as gram-negative E. coli and gram-positive S. aureus. The Minimum Inhibitory Concentration (MIC) of Fe NPs for E. coli and S. aureus was calculated as 32 μg/mL and 64 μg/mL, respectively.

Radini IA ，Hasan N ，Malik MA ，Khan Z ... -  《-》

Leucas aspera mediated multifunctional CeO2 nanoparticles: Structural, photoluminescent, photocatalytic and antibacterial properties.

Spherical shaped cerium dioxide (CeO2) nanoparticles (NPs) were synthesized via bio mediated route using Leucas aspera (LA) leaf extract. The NPs were characterized by PXRD, SEM, UV-Visible techniques. Photoluminescence (PL), photocatalysis and antibacterial properties of NPs were studied. PXRD patterns and Rietveld analysis confirm cubic fluorite structure with space group Fm-3m. SEM results evident that morphology of the NPs was greatly influenced by the concentration of LA leaf extract in the reaction mixture. The band gap energy of the NPs was found to be in the range of 2.98-3.4 eV. The photocatalytic activity of NPs was evaluated by decolorization of Rhodamine-B (RhB) under UVA and Sun light irradiation. CeO2 NPs show intense blue emission with CIE coordinates (0.14, 0.22) and average color coordinated temperature value ∼148,953 K. Therefore the present NPs quite useful for cool LEDs. The superior photocatalytic activity was observed for CeO2 NPs with 20 ml LA under both UVA and Sunlight irradiation. The enhanced photocatalytic activity and photoluminescent properties were attributed to defect induced band gap engineered CeO2 NPs. Further, CeO2 with 20 ml LA exhibit significant antibacterial activity against Escherichia coli (EC) and Staphylococcus aureus (SA). These findings show great promise of CeO2 NPs as multifunctional material for various applications.

Malleshappa J ，Nagabhushana H ，Sharma SC ，Vidya YS ，Anantharaju KS ，Prashantha SC ，Daruka Prasad B ，Raja Naika H ，Lingaraju K ，Surendra BS ... -  《-》