Retraction: Anti-cancer activity of hierarchical ZSM-5 zeolites synthesized from rice-based waste materials.

[This retracts the article DOI: 10.1039/C7RA11763A.].

Multifunctional Core-Shell NiFe2O4 Shield with TiO2/rGO Nanostructures for Biomedical and Environmental Applications.

Multifunctional core@shell nanoparticles have been synthesized in this paper through 3 stages: NiFe2O4 nanoparticles by microwave irradiation using Pedalium murex leaf extract as a fuel, core@shell NiFe2O4@TiO2 nanoparticles by sol-gel, and NiFe2O4@TiO2@rGO by sol-gel using preprepared reduced graphene oxide obtained by modified Hummer's method. XRD analysis confirmed the presence of both cubic NiFe2O4 spinel and tetragonal TiO2 rutile phases, while Raman spectroscopy analysis displays both D and G bands (I D /I G = 1.04) associated with rGO. Morphological observations by HRTEM reveal a core-shell nanostructure formed by NiFe2O4 core as confirmed by SAED with subsequent thin layers of TiO2 and rGO. Magnetic measurements show a ferromagnetic behavior, where the saturation magnetization drops drastically from 45 emu/g for NiFe2O4 to 15 emu/g after TiO2 and rGO nonmagnetic bilayers coating. The as-fabricated multifunctional core@shell nanostructures demonstrate tunable self-heating characteristics: rise of temperature and specific absorption rate in the range of ΔT = 3-10°C and SAR = 3-58 W/g, respectively. This effectiveness is much close to the threshold temperature of hyperthermia (45°C), and the zones of inhibition show the better effective antibacterial activity of NTG against various Gram-positive and Gram-negative bacterial strains besides simultaneous good efficient, stable, and removable sonophotocatalyst toward the TC degradation.

In-vitro anti-cancer activity of organic template-free hierarchical M (Cu, Ni)-modified ZSM-5 zeolites synthesized using silica source waste material.

The present paper is focused on a simple and economical route to synthesize the organic template-free hierarchical pure and M (Cu, Ni)-modified ZSM-5 zeolites (1%, 3% and 5%) using hydrothermal treatment in the presence of silica rich rice husk ash and its application studies through the evaluation of their anti-cancer activity on A459 human lung epithelial cancer cell lines. The physical properties of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, high resolution scanning electron microscopy, high resolution transmission electron microscopy, N2 adsorption/desorption techniques and thermogravimetric analysis respectively. These metals modified hierarchical ZSM-5 zeolites showed considerable in-vitro anticancer efficiency towards human lung cancer (A549) cell lines through (3-(4, 5-dimethyl thiazolyl)-2, 5-diphenyl tetrazolium bromide) MTT assay. Among the all M (Cu, Ni)-modified ZSM-5 zeolites, 5% Cu-ZSM-5 zeolites showed higher potential cytotoxicity against A459 cell lines. The possible mechanism was explored from the fundamental signaling pathways of cell death by hierarchical metal modified ZSM-5 zeolites in A459 human lung epithelial cancer cell lines. Finally, our experimental results revealed that the organic template-free hierarchical pure and M (Cu, Ni)-modified ZSM-5 zeolites have significant anti-cancer mediating action by inducing oxidative stress to intercede DNA damage and can be considered as a potential applicant in the biomedical field.

Investigation on preferably oriented abnormal growth of CdSe nanorods along (0002) plane synthesized by henna leaf extract-mediated green synthesis.

The theme of this work is to highlight the significance of green plant extracts in the synthesis of nanostructures. In asserting this statement, herein, we report our obtained results on the synthesis of hexagonal CdSe nanorods preferably oriented along (0002) plane through henna leaf extract-mediated reaction along with a discussion about the structural, morphological and optical properties of the synthesized nanorods. The possible mechanism for the synthesis of CdSe nanorods was explored. The formation of nanorods along (0002) plane was confirmed by the relatively high intensity of the (0002) peak in X-ray diffraction pattern. To account for the experimentally realistic condition, we have calculated the surface energies of hexagonal CdSe surface slabs along the low indexed (0002), [Formula: see text] and [Formula: see text] plane surfaces using density functional theory approach and the calculated surface energy value for (0002) surface is 802.7 mJ m-2, which is higher than [Formula: see text] and [Formula: see text] surfaces. On realizing the calculated surface energies of these slabs, we determined that the combination of [Formula: see text] and [Formula: see text] planes with lower surface energies will lead to the formation of CdSe nanorods growth along (0002) orientation. Finally, we argue that the design of new greener route for the synthesis of novel functional nanomaterials is highly desired.

Green synthesis of NiO nanoparticles using Aegle marmelos leaf extract for the evaluation of in-vitro cytotoxicity, antibacterial and photocatalytic properties.

In the present study, we report the green synthesis of NiO nanoparticles using Aegle marmelos as a fuel and this method is ecofriendly and cost effective. The plant Aegle marmelos is used in the field of pharmaceuticals to cure diseases like chronic diarrhea, peptic ulcers and dysentery in India for nearly 5 centuries. The as-prepared nanoparticles were confirmed as pure face centered cubic phase and single crystalline in nature by XRD. The formation of agglomerated spherical nanoparticles was shown by HR-SEM and HR-TEM images. The particle size calculated from HR-SEM was in the range 8-10 nm and it matches with the average crystallite size calculated from the XRD pattern. NiO shows intense emission peaks at 363 and 412 nm in its PL spectra. The band gap of 3.5 eV is observed from DRS studies and the formation of pure NiO is confirmed by FT-IR spectra. The as-prepared NiO nanoparticles show super paramagnetic behavior, when magnetization studies are carried out. It is then evaluated for cytotoxic activity towards A549 cell culture, antibacterial activity and photocatalytic degradation (PCD) of 4­chlorophenol (4­CP), which is known as the endocrine disrupting chemical (EDC). From the results, it is found that the cell viability of A549 cells was effectively reduced and it showed better antibacterial activity towards gram positive bacterial strains. It is also proved to be an efficient and stable photocatalyst towards the degradation of 4­CP.

Bioreduction potentials of dried root of Zingiber officinale for a simple green synthesis of silver nanoparticles: Antibacterial studies.

Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV-Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of -1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly.

Facile synthesis of heterostructured cerium oxide/yttrium oxide nanocomposite in UV light induced photocatalytic degradation and catalytic reduction: Synergistic effect of antimicrobial studies.

Ceria (CeO2) is an exciting alternative noble metal catalyst, because it has ability to release and absorb oxygen in the redox system, and function as an oxygen buffer. In this study, heterostructured catalysts consisting of CeO2/Y2O3 nanocomposites were successfully synthesized by hydrothermal method in the presence of sodium hydroxide as a reducing agent from cerium nitrate and yttrium nitrate as a precursor which was then evaluated for its photocatalytic activity in the degradation of Rhodamine B (RhB) synthetic dye. Scanning electron microscopy (SEM) imparts the surface morphology and size of the prepared sample. Elemental compositions and the purity of the nanoparticles are proved by energy dispersive X-ray Spectroscopy (EDX). CeO2/Y2O3 nanoparticles were made up of CeO and YO bonds which are confirmed by Fourier transform infrared spectroscopy (FTIR). Synthesis temperature and pressure, during hydrothermal reactions, plays a critical role in controlling the shape, size, oxygen vacancy concentration, and low temperature reducibility in CeO2 based nanocomposites. The lattice constants and oxygen vacancy concentrations of ceria nanoparticles also depend upon the concentration of hydroxide ion which leads to better morphology at low temperature and pressure. Hydrogenation of p-nitrophenol to p-aminophenol with a reducing agent is conveniently carried out in aqueous medium by using this binary metal oxide catalyst. Further, the photocatalytic performance of the synthesized nanoparticles was monitored by photocatalytic degradation of Rhodamine B synthetic dye under UV light irradiation. To get maximum photocatalytic degradation (PCD) efficiency, we have used H2O2 for the generation of excess reactive oxygen species (ROS). In addition, the antibacterial activity of nanoparticles against bacteria was also examined. The observed antibacterial activity results are comparable with the results obtained using the standard antibiotic.

High performance multifunctional green Co3O4 spinel nanoparticles: photodegradation of textile dye effluents, catalytic hydrogenation of nitro-aromatics and antibacterial potential.

Tricobalt tetraoxide (Co3O4), a spinel-structured nanoparticle which possesses mixed oxidation states, has been synthesized via a Punica granatum (P. granatum, pomegranate) seed extract-mediated green reaction and has been investigated for its superior catalytic activity in three applications, which include (i) photodegradation of textile dye effluents (TDE) collected from the dyeing industry, Tiruppur, Tamil Nadu, India, (ii) catalytic hydrogenation of nitro-aromatic pollutants such as 4-nitrophenol and 4-nitroaniline, and (iii) antibacterial potential in biomedical applications. Prior to the application studies, the synthesized Co3O4 spinel nanoparticles (Co3O4-NPs) were characterized by well-known established techniques such as X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and Raman and FT-IR spectroscopies. We have also discussed the probable mechanism and kinetic studies of the catalytic activity of the Co3O4-NPs. Finally, we concluded that the design and development of novel, economic and green synthesis-mediated catalysts such as Co3O4-NPs can exhibit efficient catalytic activity in diverse fields, which is necessary for environmental remediation.

Photocatalytic degradation effect of malachite green and catalytic hydrogenation by UV-illuminated CeO2/CdO multilayered nanoplatelet arrays: Investigation of antifungal and antimicrobial activities.

CeO2/CdO multi-layered nanoplatelet arrays have been synthesized by sol-gel method at two different temperatures using Citrus limonum fruit extract and the effect of particle size on the photocatalytic performance is studied. The particle size and phases was analysed by X-ray diffraction pattern (XRD) which brought out the formation of cubic phase in the synthesized samples. Field Emission Scanning electron microscopy (FESEM) revealed the surface morphology and made up of cumulative form of platelet shaped arrays with an average size of 10nm. The elemental composition and the purity of the nanomaterials were confirmed by Energy Dispersive X-ray spectroscopy (EDX). CeO2/CdO multilayered binary metal oxide nanoplatelet arrays were formed which was further explored with Fourier transform infrared spectroscopy (FTIR), it reveals that the nanocomposites contain CeO and CdO bonds. Determination of the direct and indirect bandgap energy of the nanoplatelet arrays was carried out by UV-Vis-DRS studies. In MG degradation, both the hole (h+) and hydroxyl radical (OH) played a major role than the superoxide radical (O2-). Possible photo degradation mechanisms are proposed and discussed in this article. CeO2/CdO multi-layered nanoplatelet arrays showed antibacterial activity and among the tested ones, it showed better growth inhibition towards P. aeruginosa MTCC73. Thus, this greener synthetic procedure was a highly effective method due to low-cost, highly effective UV light responsive material for environmental safety.

Antibacterial activity of silver nanoparticles synthesized from serine.

Silver nanoparticles (Ag NPs) were synthesized by a simple microwave irradiation method using polyvinyl pyrrolidone (PVP) as a capping agent and serine as a reducing agent. UV-Visible spectra were used to confirm the formation of Ag NPs by observing the surface plasmon resonance (SPR) band at 443nm. The emission spectrum of Ag NPs showed an emission band at 484nm. In the presence of microwave radiation, serine acts as a reducing agent, which was confirmed by Fourier transformed infrared (FT-IR) spectrum. High-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning electron microscopy (HR-SEM) were used to investigate the morphology of the synthesized sample. These images showed the sphere-like morphology. The elemental composition of the sample was determined by the energy dispersive X-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NPs. The electrochemical behavior of the synthesized Ag NPs was analyzed by the cyclic voltammetry (CV). Antibacterial experiments showed that the prepared Ag NPs showed relatively similar antibacterial activities, when compared with AgNO3 against Gram-positive and Gram-negative bacteria.

Comparative studies on influence of morphology and La doping on structural, optical, and photocatalytic properties of zinc oxide nanostructures.

A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials with different morphologies such as nanoflakes, spherical nanoparticles (SNPs), and nanorods. The concentration of the capping agent, Triton X-100, is a key factor in the morphological control of ZnO nanostructures. The formation of different morphologies of ZnO was confirmed by HR-SEM and HR-TEM. XRD data showed the formation of single-phase ZnO with the wurtzite crystal structure. The influence of La contents on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO SNPs was investigated systematically. The influence of the ZnO morphologies on the photocatalytic degradation (PCD) of Bisphenol A (BPA) as a model reaction is evaluated and discussed in terms of surface area, crystal growth habits, particle size, and oxygen defects. The results indicated that the particle size is an important factor for the enhancement of PCD. Furthermore, the effect of different photocatalytic reaction parameters on the resulting PCD efficiency of ZnO SNPs was investigated.