S. Velmurugan

RETRACTED: Synthesis of silver nanoparticles using A. indicum leaf extract and their antibacterial activity

Green synthesis of silver nanoparticles has been achieved using environmentally acceptable plant extract. It is observed that Abutilon indicum leaf extract can reduce silver ions into silver nanoparticles within 15 min of reaction time. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV-Vis spectrophotometer analysis. The mean particle diameter of silver nanoparticles was calculated from the XRD pattern. FT-IR spectra of the leaf extract after the development of nanoparticles are determined to allow identification of possible functional groups responsible for the conversion of metal ions to metal nanoparticles. The AgNPs thus obtained showed highly potent antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus subtilis) and Gram-negative (Salmonella typhi and Escherichia coli) microorganisms.

RETRACTED: Synthesis, characterization and catalytic activity of silver nanoparticles using Tribulus terrestris leaf extract

Biomediated silver nanoparticles were synthesized with the aid of an eco-friendly biomaterial, namely, aqueous Tribulus terrestris extract. Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous T. terrestris leaf extracts as both the reducing and capping agent. Silver ions were rapidly reduced by aqueous T. terrestris leaf extracts, leading to the formation of highly crystalline silver nanoparticles. An attempt has been made and formation of the silver nanoparticles was verified by surface plasmon spectra using an UV-vis (Ultra violet), spectrophotometer. Morphology and crystalline structure of the prepared silver nanoparticles were characterized by TEM (Transmission Electron Microscope) and XRD (X-ray Diffraction), techniques, respectively. FT-IR (Fourier Transform Infrared), analysis suggests that the obtained silver nanoparticles might be stabilized through the interactions of carboxylic groups, carbonyl groups and the flavonoids present in the T. terrestris extract.

RETRACTED: Green synthesis of zinc oxide nanoparticles using Moringa oleifera leaf extract and evaluation of its antimicrobial activity

The development of semiconductor materials made a considerable progress of catalytic technologies. In the present study, a simple and eco-friendly chemical direction for the synthesis of zinc oxide nanoparticles (ZnO NPs) using leaf extract of Moringa oleifera has been used. The prepared ZnO NPs were characterized various techniques such as UV-Vis absorption spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectroscopy (PL). XRD analysis revealed the wurtzite hexagonal structure of ZnO NPs. FT-IR confirmed the presence of functional groups of both leaf extract and ZnO NPs. The particles size, morphology and topography determined from FE-SEM. The intense and narrow width of zinc and oxygen have high purity and crystalline were identified using EDX. UV-Vis absorption showed the characteristic absorption peak of ZnO NPs. The results of antimicrobial activities revealed that maximum zones of inhibition was observed Gram (+ve) positive bacteria and followed by the Gram (-ve) negative bacteria and fungal at concentration of 200μg/mL of ZnO NPs.

RETRACTED: Green synthesis of silver nanoparticles from Gloriosa superba L. leaf extract and their catalytic activity

The present work focuses the use of aqueous extract of Gloriosa superba Linn. (Glory Lily) for producing silver nanoparticles (AgNPs) from silver nitrate aqueous solution. Phytochemical analysis of the extract revealed the presence of alkaloid, amino acids, carbohydrates and proteins in the extract and they serve as effective reducing and capping agents for converting silver nitrate to silver nanoparticles. The nanoparticles were characterised by UV (Ultra violet), FT-IR (Fourier Transform Infrared), XRD (X-ray diffraction), TEM (Transmission Electron Microscope) SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray), and PL (Photoluminescence) studies. Moreover, the catalytic activity of synthesized AgNPs in the reduction of methylene blue was studied by UV-vis spectrophotometer. The synthesized AgNPs are observed to have a good catalytic activity on the reduction of methylene blue by G. superba extract which is confirmed by the decrease in absorbance maximum values of methylene blue with respect to time using UV-vis spectrophotometer.

Green synthesis of silver nanoparticles using Croton sparsiflorus morong leaf extract and their antibacterial and antifungal activities.

Biologically synthesized nanoparticles have been widely used in the field of medicine. Especially, silver nanoparticles (Ag NPs) synthesized by the leaf extract lead the biological activity. In the present work, the synthesized Ag NPs by using the leaf extract of Croton sparsiflorus morong Ag NPs were characterized by using UV-Visible (UV-Vis) absorption spectroscopy, X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) along with Energy Dispersive X-ray (EDX) Spectroscopy and Fourier Infrared (FT-IR) Spectroscopy, respectively. UV-Vis peak at 457 nm confirmed the Ag NPs due to the absorption. Cubic structural analysis and 16 nm particle size of the Ag NPs were calculated by using XRD analysis. The surface morphology along with the presence of Ag NPs was identified by using FE-SEM and EDX, respectively. The FT-IR study revealed with the functional groups of the Ag NPs. Finally, the present research has been explored to exhibit the significant antimicrobial activities.

Rapid biological synthesis of silver nanoparticles using Leucas martinicensis leaf extract for catalytic and antibacterial activity

A novel green approach for the synthesis and stabilization of silver nanoparticles (AgNPs) using water extract of Leucas martinicensis leaf has been developed. As obtained, the nanoparticles are characterized by UV-visible (UV-Vis), transmission electron microscope (TEM), and X-ray diffraction (XRD). The crystalline nature of the AgNPs is confirmed by the prominent peaks in the XRD pattern. FTIR spectra suggest that the possible biomolecules are responsible for the efficient stabilization of the sample. The effects of leaf quantity on the biosynthesis of AgNPs are investigated by UV-Vis spectrophotometer. The synthesized AgNPs are observed to have a good catalytic activity on the reduction of methylene blue by L. martinicensis leaf. This is confirmed by the decrease in absorbance maximum values of methylene blue with respect to time through UV-Vis spectrophotometer. Moreover, the antibacterial activity of synthesized AgNPs against Staphylococcus aureus, Bacillus subtilis, Salmonella typhi, and Escherichia coli are screened.

Retraction notice to “Synthesis, characterization and catalytic activity of Silver Nanoparticles Using Tribulus terrestris Leaf Extract” [SAA (2014) 88-93]

This article has been retracted: please see Elsevier Policy on Article described as different samples. Figure 3 displays duplicated data despite Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor. The article contains duplicate images (Fig. 5A and B aswell as Fig. 5C and D) which differ only in magnification and orientation despite being