Malik Maaza

A comparative study on the morphological features of highly ordered MgO:AgO nanocube arrays prepared via a hydrothermal method

II–VI semiconductor nanotubes are a recently developed class of nanomaterials whose unique photophysical properties are helping to create a new generation of nanomaterials in the field of photonics and microelectronics. In this report, we examine the progress in adapting these nanomaterials for several optoelectronics applications followed by characterization studies. Magnesium oxide and silver oxide (MgO:AgO) nanoparticles were synthesized using a hydrothermal method by taking magnesium nitrate, silver oxide and glycine. X-ray diffraction (XRD) results showed that the peaks are consistent with a pure phase cubic structure of MgO. The XRD pattern also confirmed the crystallinity and phase purity of the sample. Nanocrystal sizes were found to be up to 25 nm as revealed by XRD and HRTEM. Photoluminescence measurement (PL) reveals the systematic shift of the emission band towards lower wavelength thereby ascertaining the quantum confinement effect.

Green synthesis of NiO nanoparticles using Moringa oleifera extract and their biomedical applications: Cytotoxicity effect of nanoparticles against HT-29 cancer cells

Green protocols for the synthesis of nickel oxide nanoparticles using Moringa oleifera plant extract has been reported in the present study as they are cost effective and ecofriendly, moreover this paper records that the nickel oxide (NiO) nanoparticles prepared from green method shows better cytotoxicity and antibacterial activity. The NiO nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM), Energy dispersive X-ray analysis (EDX), and Photoluminescence spectroscopy (PL). The formation of a pure nickel oxide phase was confirmed by XRD and FTIR. The synthesized NiO nanoparticles was single crystalline having face centered cubic phase and has two intense photoluminescence emissions at 305.46nm and 410nm. The formation of nano- and micro-structures was confirmed by HRTEM. The in-vitro cytotoxicity and cell viability of human cancer cell HT-29 (Colon Carcinoma cell lines) and antibacterial studies against various bacterial strains were studied with various concentrations of nickel oxide nanoparticles prepared from Moringa oleifera plant extract. MTT assay measurements on cell viability and morphological studies proved that the synthesized NiO nanoparticles posses cytotoxic activity against human cancer cells and the various zones of inhibition (mm), obtained revealed the effective antibacterial activity of NiO nanoparticles against various Gram positive and Gram negative bacterial pathogens.

Synthesis and Substrate-Aided Alignment of Porphyrinated Poly(ethylene oxide) (PEO) Electrospun Nanofibers

Aligned and unaligned vanadium (IV) oxide meso-tetraphenyl porphine (VMP)/polyethylene oxide (PEO) hybrid nanofibers have been successfully synthesized by electrospinning technique. The nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), optical microscopy and scanning electron microscopy (SEM). The SEM and AFM analyses of the morphology showed that the nanofibers are cylindrical with diameters ranging from 400–700 nm. The AFM analysis also confirmed that the aligned nanofibers deposited on a small metallic spring are smoother than the unaligned ones deposited on FTO. FTIR analysis showed that the polar environment provided by the phenyl groups of VMP molecules modified the chemical configuration of PEO molecules, and XRD studies indicated that the VMP molecules were homogeneously distributed within the PEO matrix.

Effective Ammonia Detection Using n-ZnO/p-NiO Heterostructured Nanofibers

Metal-oxide heterostructures are very important materials for developing various toxic gas/chemical detection sensor systems. However, the major factors, such as sensitivity, selectivity, stability, response, and recovery times of the sensors, still need to be optimized for practical technological applications. Low-dimensional materials have shown tremendous potential to solve majority of the critical issues due to their surface chemistry than that of their bulk form. In this paper, the role of nanostructured n-ZnO/p-NiO heterostructure as room temperature (RT) ammonia sensor has been investigated. Toward this paper, the electrospinning method was employed to prepare heterostructure metal-oxides blended with polyvinyl alcohol (n-ZnO/p-NiO) nanofibers. The systematic characterizations of the obtained n-ZnO/p-NiO heterostructure were performed using X-Ray diffractometer, scanning electron microscope, and photoluminescence spectrophotometer. Furthermore, the RT ammonia sensing characteristics were investigated.

Synthesis and characterization studies of MgO:CuO nanocrystals by wet-chemical method.

In this report, we examine the progress in adapting these nanomaterials for several predominantly photonics device fabrication by wet-chemical method. Nanocomposite of magnesium oxide (MgO) with copper oxide (CuO) doped nanoparticles were characterized by X-ray powder diffraction (XRD) and the observed peaks are quite agreeable with the pure phase cubic structure. High-resolution transmission electron microscopic (HR-TEM) results reveal that the resultant nanopowders are porous and agglomerated with polycrystalline nano-entities. Field emission of selected-area electron diffraction (SAED) studies showed that the average size of the nanoparticles were 20nm. Photoluminescence spectra of MgO:CuO were investigated, showing emission peaks around 375nm relating to new energy levels induced by defects or defect levels generation and confocal micro-Raman images indicated that the chemical molecular vibrational band structure and morphology of the product which is spherical shaped nanoparticles with an average particle size of ∼25nm with standard deviation. The electrochemical response of MgO:CuO which is proves that the nano-copper/magnesium has high functionality due to the small size and it has higher electrochemical activity without any modifications.

Sageretia thea (Osbeck.) mediated synthesis of zinc oxide nanoparticles and its biological applications

AIM To investigate the physical and biological properties of bioinspired zinc oxide (ZnO) nanoparticles via aqueous leaf extracts of Sageretia thea. EXPERIMENTAL Nanoparticles of size approximately 12.4 nm were extensively characterized. In vitro antimicrobial, cytotoxic, biocompatible and enzyme inhibition assays were performed. RESULTS Significant antimicrobial activities with and without UV illumination are reported. Bioinspired ZnO nanoparticles were found effective against fungal strains. MTT assay was performed to check the leishmanicidal activity against promastigotes (IC50: 6.2 μg/ml) and amastigotes (IC50: 10.87 μg/ml) of Leishmania tropica. Brine shrimp lethality was also indicated by bioinspired ZnO nanoparticles (IC50: 21.29 μg/ml). CONCLUSION Hemocompatible nature of bioinspired nanoparticles was revealed. Furthermore, the antioxidant activities were performed. In addition, significant protein kinase while insignificant alpha amylase inhibition were recorded.

Biosynthesis of iron oxide (Fe2O3) nanoparticles via aqueous extracts of Sageretia thea (Osbeck.) and their pharmacognostic properties

ABSTRACT Sageretia thea (Osbeck.) was used as an effective chelating agent for the biosynthesis of iron oxide nanoparticles (IONPs) and extensively characterized through XRD, FTIR, Raman spectroscopy, Energy Dispersive Spectroscopy, HR-SEM/TEM and SAED. Antibacterial assays against five human pathogenic bacterial strains were carried out and minimum inhibitory concentrations were calculated. Pseudomonas aeruginosa (MIC: 7.4 µg/mL) was the most susceptible strain to biosynthesized IONPs. All of the fungal strains showed susceptibility to the IONPs. MTT cytotoxic assay was carried out against the promastigote and amastigote cultures of Leishmania tropica and their IC50 values were calculated as 17.2 and 16.75 µg/mL. The cytotoxic potential was further assessed using brine shrimps, and the IC50 was calculated as 16.46 µg/mL. Moderate antioxidant activities were reported. Human RBCs and macrophages were found to be biocompatible with biogenic IONPs (IC50 > 200 µg/mL). GRAPHICAL ABSTRACT

Microwave-assisted synthesis of simonkolleite nanoplatelets on nickel foam-graphene with enhanced surface area for high-performance supercapacitors

Simonkolleite (Zn5(OH)8Cl2·H2O) nanoplatelets has been deposited on nickel foam-supported graphene by using an efficient microwave-assisted hydrothermal method. The three-dimensional (3D) porous microstructure of the as-fabricated nickel foam-graphene/simonkolleite (NiF-G/SimonK) composite is beneficial to electrolyte penetration and ions exchange, whereas graphene provide improved electronic conductivity. Structural and morphological characterizations confirmed the presence of highly crystalline hexagonal-shaped nanoplatelets of simonkolleite. Field emission scanning electron microscope (FE-SEM) of the NiF-G/SimonK composite revealed that the SimonK nanoplatelets were evenly distributed on the surface of NiF-G and interlaced with each other, resulting in a higher specific surface area of 35.69 m(2) g(-1) compared to SimonK deposited directly on NiF 17.2 m(2) g(-1). Electrochemical measurements demonstrated that the NiF-G/SimonK composite exhibit a high specific capacitance of 836 F g(-1) at a current density of 1 A g(-1), and excellent rate capability and cycling stability with capacitance retention of 92% after 5000 charge/discharge cycles.

Sageretia thea (Osbeck.) modulated biosynthesis of NiO nanoparticles and their in vitro pharmacognostic, antioxidant and cytotoxic potential

Abstract NiO nanoparticles are biosynthesized using Sageretia thea (Osbeck.) aqueous leave extracts and their biological activities are reported. Nanoparticles (∼18 nm) were characterized through XRD, ATR-FTIR, EDS, SAED, HR-SEM/TEM and Raman spectroscopy. Antibacterial activity was investigated against six pathogenic bacterial strains (gram positive and gram negative) and their corresponding minimum inhibitory concentrations (MICs) were calculated. UV-exposed nanoparticles were investigated to have reduced MICs relative to the NiO nanoparticles have not been exposed to UV. Moderate linear fungal growth inhibition was observed while Mucor racemosus (percentage inhibition 64% ± 2.30) was found to be most susceptible. Cytotoxicity was confirmed using brine shrimps lethality assay (IC50 42.60 μg/ml). MTT cytotoxicity was performed against Leishmania tropica-KWH23 promastigotes and amastigotes revealed significant percentage inhibition across the applied concentrations. IC50 values were calculated as 24.13 μg/ml and 26.74 μg/ml for the promastigote and amastigote cultures of Leishmania tropica. NiO nanoparticles were found. Moderate, antioxidant potential was concluded through assays like DPPH, TAP and TAC. Furthermore, protein kinase inhibition and alpha amylase inhibition is also reported. Graphical Abstract

Synthesis and Characterization of Electrospun Poly(ethylene oxide)/Europium-Doped Yttrium Orthovanadate (PEO/YVO4:Eu3+) Hybrid Nanofibers

Europium-doped yttrium orthovanadate/polyethylene oxide nanofibers were fabricated by firstly, synthesizing crystalline YVO4:Eu3+ nanoparticles using an aqueous precipitation method followed by electrospinning of PEO/YVO4:Eu3+ polymer composites. X-ray diffraction patterns showed that the nanoparticles exhibited well-defined peaks that were indexed as the tetragonal phase of YVO4. No additional peaks of other phases were observed indicating that Eu3+ ions were effectively built into the YVO4 host lattice. The photoluminescence spectra for the nanofibers showed peaks at 593, 615, 650, and 698 nm which was ascribed to the 5D0− 7F1, 5D0− 7F2, 5D0− 7F3 and 5D0− 7F4 transitions of Eu3+. Due to an efficient energy transfer from vanadate groups to Eu3+, the composite nanofibers showed a strong red emission under ultraviolet excitation characteristic of the red luminescence of the europium ion. The results demonstrate that this synthetic approach could prove to be viable for the fabrication of rare earth/polymer composite nanofibers intended for luminescent device applications.