Sharda Sundaram Sanjay

Application of ZnO nanoparticles in influencing the growth rate of Cicer arietinum

In this work, ZnO nanoparticles (NPs) have been synthesised by hydrothermal method. This hydrothermally synthesised product has been characterised by powder X-ray diffraction and field emission scanning electron microscopy (FE-SEM) for the study of crystal structure and morphology/size. FE-SEM image revealed that ZnO NPs are spherical in shape with a diameter of 20–30 nm. The photoluminescence study of these NPs revealed that ZnO NPs consist of three emission peaks at 401, 482 and 524 nm. The UV emission peak at 401 nm is the band edge emission; however, the blue-green emission at 482 nm and green emission at 524 nm is related to defects. These ZnO NPs are used during the seed germination and root growth of Cicer arietinum. The effect of ZnO NPs has been observed on the seed germination and root growth of C. arietinum seeds. The effect of these ZnO NPs on the reactivity of phytohormones, especially indole acetic acid (IAA) involved in the phytostimulatory actions, is also carried out. Due to oxygen vacancies, the oxygen deficient, i.e. zinc-rich ZnO NPs increased the level of IAA in roots (sprouts), which in turn indicate the increase in the growth rate of plants as zinc is an essential nutrient for plants.

Formation of stable and strong green luminescent ZnO/Cd(OH)2 core-shell nanostructure by sol–gel method

Highly stable and strong green luminescent ZnO/Cd(OH)2 core-shell nanoparticles have been synthesised by simple sol–gel route. X-ray diffraction (XRD) and energy dispersive analysis of X-rays confirm the formation of ZnO/Cd(OH)2 core-shell nanoparticles. The XRD and UV–visible spectroscopy shows that ZnO core size can be efficiently engineered by varying initial precursor ratio. The photoluminescence emission spectra showed the remarkably stable and enhanced visible (green) emission from suspended ZnO/Cd(OH)2 nanoparticles in comparison with bare ZnO nanoparticles. It was postulated that Cd(OH)2 layer at the surface of ZnO nanoparticles prevent the agglomeration of nanoparticles and efficiently assist the trapping of hole at the surface site, a first step necessary for visible emission.

Cell membrane protective efficacy of ZnO nanoparticles

Excessive free radicals are generated in body due to unbalanced oxidants and antioxidants ratio which results into oxidative stress. Many diseases, as well as exposure to toxins and even some normal activities are known to cause oxidative stress. Aldehydes are the end products of a chemical reaction that starts with an attack on phospholipids by the oxygen based hydroxyl radical (OH) to form unstable compounds known as lipid hydroperoxides. Zinc oxide (ZnO) nanoparticles due to their capability of forming excitonic pair (e-, h+) serve as an ROS scavenger. ZnO nanoparticles were synthesized and characterized by XRD and SEM. Lipid peroxidation inhibition assay in rat tissue homogenate (liver, kidney, brain and spleen) was used to asses the protection against the cell membrane damage. Nanoparticles accounted for maximum inhibition of lipid peroxidation in liver tissue at a concentration of 600μg/ml.

A Brief Manifestation of Nanotechnology

Nanotechnology is basically focused on the fabrication of nanomaterials based on the manipulation, control, and integration of atoms and molecules at nanometer scale, due to which there develops sudden change in the size-dependent properties and functions. We have to integrate chemistry, physics and biology to form materials, structures, components, devices, and systems at the nanoscale level. In the metric system, prefix “nano-” refers to one-billionth (0.000 000 001 = 10−9) of the base unit. In the nanoscale, at least one of the particle’s dimensions (height, width, or depth) should be at less than 100 nm. At this level, the chemical reactivity changes dramatically due to the reduction of particle size. This change occurs as a function of the structure and the density of electrons in the outermost electronic energy levels. Along with the physical properties such as optical, electrical, and thermal properties, magnetic characteristics may also change which in-turn depend on the distribution of electrons in the outermost energy levels, leads to the novel optical, electrical, magnetic behaviors and changes in the surface dependent properties. Because of the increase in the surface-to-volume ratio at the nanoscale level the properties of the material become strongly dependent (controllable) on the surface of the materials. The nanomaterials may be classified in number of ways, viz., based on: (i) dimensionality (ii) surface morphology (iii) crystalline forms (iv) chemical nature (v) chemical composition (vi) magnetic behavior (vii) functionalization or (viii) applications. But none of these classifications can be considered as absolute one. They are usually composites or hybrid in nature because in majority of cases organic compounds are used to stabilize them through capping or functionalization during synthesis. Magnetic nanomaterials have giant spins, which may be described as a single magnetic domain having uniaxial anisotropy, their EMR signals can be exploited for various biomedical and many other applications. Number of biomedical applications of nanoparticles is becoming possible because of their specific physicochemical properties and controllable dimensions which range from a few nanometers to nearly tens of nanometer, due to which they come in the size range smaller than that of a plant or animal cells having submicron size domain.