纳米科学杂志：当前研究

This work presents and discusses the study of ZnO (zinc oxide) as nanoparticles and its idiosyncratic characteristics. Zinc oxide nanoparticles were synthesized employing a simple sol- gel method, with zinc chloride, zinc nitrate and sodium hydroxide as starting materials at room temperature. The synthesized ZnO nanoparticles were then characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscope (TEM) and UV-Visible spectroscopy. SEM and TEM images reveal hexagonal morphology of ZnO obtained, with average crystalline size. This was determined from the full width at half maximum of XRD peaks by using Debye-Scherrer’s Formula. Moreover, interpretation through UV-Visible absorption spectra supported a high absorption confirming its transcendent electrical and optoelectronic properties. It was further mathematically showed that ZnO nanoparticles can be efficiently utilized as additives in base lubricants to diminish abrasion and wear, enhancing tribological properties.

Cerium oxide nanoparticles (CeO₂ NPs) were synthesized through chemical (co-precipitation method) (C-CeO₂ NPs) and green synthetic route (A. indica leaf extract) (G-CeO₂ NPs) and comparative studies were also carried out in the first time. From the XRD Pattern of C-CeO₂ and G-CeO₂ NPs revealed that both were in cubic phase. The morphological and elemental compositions were identified by FESEM, TEM and EDAX spectra. The optical characterizations were carried out using UV-Visible and Photoluminescence spectral analysis. Further the FT-IR and FT-Raman analysis were also confirmed to formation of CeO₂ nanoparticles. The oxidation states of the elements Ce (3d), C (1s) and O (1s) were confirmed by XPS studies. The green synthesized CeO2 NPs possessed a higher antibacterial activity than chemical CeO₂ NPs. The cytotoxic effect of C-CeO2 and G-CeO₂ NPs were analyzed in cultured (A549) human lung cancer cell line.

Polyaniline coated fibers and polyaniline-CNT fibers for solid phase microextraction of phenols from aqueous sample were compared. In the present work we established a method for preparation of polyanilie-CNT coated platinum wire (SPME Fiber) and investigated their capability to extract phenol from aqueous samples.

Nowadays, nanomaterial has been used extensively worldwide to improve the properties of the constructional materials due to many advantages that can be achieved especially improving strength/weight ratio which is highly desired by the engineers towards a green building concept by minimizing the material used and increasing the stresses levels that the structure can carry. The present research examined the mechanical properties of nano cement mortar which can lead to improvements in ferrocement to be used in the green building system. Thus 90 cubes, 50 mm, and 500 × 50 mm prisms varying thickness (t=4, 6, 8 and 10 mm) were cast and tested to determine the compressive strength, and modulus of rupture, for nano cement mortar at curing age of 28 days, In addition, 50 nano-ferrocement prisms (500 × 50 mm) with varying the thickness (t=4, 6, 8 and 10 mm), number of fine wire mesh layers, mix proportions were cast and flexural tests were carried out to determine the composite modulus of elasticity and modulus of rupture. It was observed that the compressive and flexural strengths were increased for the nano-ferrocement samples in comparison with the normal one which refers to the importance of developed mixture toward sustainable building.

Silver and its compound have been widely used since from ancient time for the treatment of bacteria and wound infections especially in patients of serious burns. The use of silver compounds has been deteriorated due to emergence of new therapeutic agents. In the past decade nanotechnology has acquired pace due to its ability of modifying metals ions into their nano range, which dramatically changes their chemical, physical and optical properties. Silver nanoparticles have been proved a potential antimicrobial agent. Recently, the use of silver nanoparticles (AgNPs) has been greatly enhanced, due to the development of antibiotic resistance against several pathogenic bacteria. The silver nanoparticles have been widely employed in biomedical industry as coatings in dressings, in medicinal devices and in the form of nanogels in cosmetics and lotions, etc. There are well established protocols for the preparation of silver nanoparticles can be broadly classified into physical, chemical and biological protocols. The physical and chemical processes often involve high temperatures/pressure for the reaction and the use of hazardous chemicals. Therefore the research in synthesis of nanoparticles by biological methods is gaining importance. Plant extracts are considered cost-effective, environment friendly and efficient alternative for the large-scale synthesis of nanoparticles. In the present review, we critically assess the role of plants in synthesis of silver nanoparticles and their biomedical applications.