A pinboard by
Tharwat Shaheen

researcher, National Research Centre


Green Approach Synthesis of Ag Nanorod via Cellulose Nanocrystal and their Cytotoxicity assessment

Since the last decades, building small structures for advanced materials design and devices with high performance became one of the basic goals of nanoscience and nanotechnology. In this regard, anisotropic inorganic nanostructured materials are particularly attractive great interest as building blocks for such purposes, due to their unique optical, biological, electronic, magnetic, and catalytic properties. Herein, this research addresses a new innovative approach for one-pot rapid synthesis of highly stabilized silver nanorods in powder form at concentration as high as feasible to be proposed in large-scale production via novel mediator, viz., cellulose nanocrystals (CNC). the best of our knowledge, this paper is the first contribution in utilization of CNC without modification in preparation of nanoparticles, in particular, silver nanorods. CNC is considered as a green biopolymer extracted from renewable sources which is biodegradable and non-toxic to humans and environment. For the first time, CNC without any surface modification in the presence of alkali is acting as both reducing and stabilizing agent for assembling of Ag nanorods. Extraction of CNC from cotton is carried out as per to acid hydrolysis (H2SO4 60% w/w) technique. Three different concentrations of silver nitrate are used in the assembling of Ag nanorods. Thorough assessments of Ag nanorods formation, structural and morphological characteristics of Ag nanorods were investigated by making use of UV–vis spectroscopy, TEM, DLS, AFM and X-ray diffraction(XRD) analysis. Also, the antibacterial activity and cytotoxicity of Ag nanorod were investigated. Research outputs signify that, Ag nanorods has been successfully prepared through an effectively approach by virtue of the textural feature of CNC as a mediator. Results revealed the great tendency of CNC toward reducing and stabilizing the as formed Ag nanorods even at high concentration. Regardless to concentration of AgNO3 used, the average sizes of Ag nanorods formed are in the range of 10-30nm higher concentration. Results also demonstrated that Ag nanorods have not merely remarkably antibacterial activity towards Gram-positive and Gram-negative bacteria, but safe for using in human life, which exhibited no effect on eukaryotic cells. Comparing these findings to conventual methods, CNC mediator provided Ag nanorod in powder form with facile, rapid, environmentally safe and industrial feasible for quick handling and transportation.


Shape and surface chemistry effects on the cytotoxicity and cellular uptake of metallic nanorods and nanospheres.

Abstract: Metallic nanoparticles (such as gold and silver) have been intensely studied for wound healing applications due to their ability to be easily functionalized, possess antibacterial properties, and their strong potential for targeted drug release. In this study, rod-shaped silver nanorods (AgNRs) and gold nanorods (AuNRs) were fabricated by electron beam physical vapor deposition (EBPVD), and their cytotoxicity toward human skin fibroblasts were assessed and compared to sphere-shaped silver nanospheres (AgNSs) and gold nanospheres (AuNSs). Results showed that the 39.94 nm AgNSs showed the greatest toxicity with fibroblast cells followed by the 61.06 nm AuNSs, ∼556 nm × 47 nm (11.8:1 aspect ratio) AgNRs, and the ∼534 nm × 65 nm (8.2:1 aspect ratio) AuNRs demonstrated the least amount of toxicity. The calculated IC50 (50% inhibitory concentration) value for the AgNRs exposed to fibroblasts was greater after 4 days of exposure (387.3 μg mL(-1)) compared to the AgNSs and AuNSs (4.3 and 23.4 μg mL(-1), respectively), indicating that these spherical metallic nanoparticles displayed a greater toxicity to fibroblast cells. The IC50 value could not be measured for the AuNRs due to an incomplete dose response curve. The reduced cell toxicity with the presently developed rod-shaped nanoparticles suggests that they may be promising materials for use in numerous biomedical applications.

Pub.: 09 Jun '15, Pinned: 28 Jul '17