Green Synthesis of Cerium Oxide Nanoparticles, Characterization, and Their Neuroprotective Effect on Hydrogen Peroxide-Induced Oxidative Injury in Human Neuroblastoma (SH-SY5Y) Cell Line.

Cerium oxide nanoparticles (CeO2NPs) have a broad scale of applications in the biomedical field due to their excellent physicochemical and catalytic properties. The present study aims to synthesize the CeO2NPs from Centella asiatica (C. asiatica) leaf extract, which has been used in Indian traditional medicine for its neuroprotective properties. The CeO2NPs were characterized by ultraviolet-visible, X-ray diffraction, Fourier transform infrared, Raman spectroscopy, scanning electron microscopy- energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The antioxidant property was evaluated by 2,2-di (4-tert-octyl phenyl)-1-picrylhydrazyl and OH radical assays. The neuroprotective potential was assessed against the oxidative stress (OS) induced by H2O2 in the human neuroblastoma (SH-SY5Y) cell line. CeO2NPs exhibited significant DPPH and OH radical scavenging activity. Our results revealed that CeO2NPs significantly increased H2O2-induced cell viability, decreased lactate dehydrogenase, protein carbonyls, reactive oxygen species generation, apoptosis, and upregulated antioxidant enzyme activity. Our findings suggest that the CeO2NPs protect the SH-SY5Y cells from OS and apoptosis, which could potentially counter OS-related neurodegenerative disorders.

Extraction of Y2 O3 :Cr3+ nanophosphor by eco-friendly approach and its suitability for white light-emitting diode applications.

Cr3+ -doped Y2 O3 (0.5-9 mol%) was synthesized by a simple solution combustion method using Aloe vera gel as a fuel/surfactant. The final obtained product was calcined at 750°C for 3 h, which is the lowest temperature reported so far for the synthesis of this compound. The calcined product was confirmed for its crystallinity and purity by powder X-ray diffraction (PXRD) studies which showed a single-phase nano cubic phosphor. The particles size estimated by Scherrer formula was in the range of 6-19 nm. The UV-vis spectra showed absorption bands at 198, 272 and 372 nm having band gap energy in the range 4.00-4.26 eV. In order to investigate the possibility of its use in white light emitting display applications, the photoluminescence properties of Cr3+ -doped Y2 O3 nanophosphors were studied at an excitation wavelength in the near ultraviolet (UV) light region (361 nm). The emission spectra consisted of emission peaks in the blue (4 F9/2  â†’ 6 H15/2 ), orange (4 F9/2  â†’ 6 H13/2 ) and red (4 F9/2  â†’ 6 H11/2 ) regions. The CIE coordinates (0.33, 0.33) lie in the white light region. Hence Y2 O3 :Cr3+ can be used for white light-emitting diode (LED) applications.

Effective fingerprint recognition technique using doped yttrium aluminate nano phosphor material.

First time the yttrium aluminate nanoparticles are used to improve the fingerprint quality. Eco-friendly green combustion process is used to synthesize YAlO3:Sm(3+) (0.5-11mol%) nanophosphor using green tea leaf extract as non-toxic and eco-friendly fuel. Powder X-ray diffraction study confirms the orthorhombic phase. The average sizes of the crystallites were found to be in the range 20-35nm. The emission peaks centered at 564, 601 and 647nm is attributed to 4f-4f (4)G5/2→(6)HJ=5/2,7/2,9/2 forbidden transitions of Sm(3+) ions. Judd-Ofelt theory is applied to experimental data for providing qualitative support by determining J-O intensity parameters. The Commission International De I-Eclairage chromaticity co-ordinates are very close to National Television System Committee standard value of white emission (x=0.296, y=0.237). Further, correlated color temperature is found to be ∼11,900K. A simple, fast, highly sensitive and low-cost method for the detection and enhancement of fingermarks in a broad range of surfaces is developed and constitutes an alternative to traditional luminescent powders.