Nanoscience has grown up considerably during the last several years as it has changed from technological innovations to extensively employed technology. It is the combination of engineering and molecular biology, resulting in the expansion and growth of structures, devices, and systems that have novel properties with sizes between 1-100nm. Nanotechnology has remarkable potential to boost many sectors of our economy and its market is growing with guarantees of exceptionally lucrative benefits that will have important financial and healthcare effects covering a wide range of areas from aerospace technology and nano-electronics to environmental remediation and healthcare. Their novel physico-chemical, thermal, and electrical properties facilitated their application in clothing, medicine, and cosmetics thereby increasing the probability of human and environmental contact with these nanoparticles. The issues have been brought up that the very qualities of nanostructured components that make them so eye-catching could possibly cause unexpected hazards/risks to health and the environment. Nano forms of carbon-based materials, metals, metal oxides, and biopolymers are being used in several industries including diagnosis, drug delivery, cosmetics, sunscreens, food, paints, electronics, sports, imaging etc. Recently, reported the annual production of Titanium dioxide TiO2 nanoparticles (NPs) is 10,000 tonnes followed by Zinc oxide ZnO NPs to be 1600 tonnes per year. The increased production and use of ZnO NPs and TiO2 NPs have enhanced the probability of their exposure in occupational and environmental settings. This has raised concerns in the public and scientific communities regarding their unanticipated and adverse effects on health and the environment. Toxicity of ZnO NPs and TiO2 NPs had been evaluated in vitro and in vivo as well as in many different lower model systems, such as Daphnia, Zebrafish, Oncorhynchus mykiss, Pimephales promelas, E. coli, etc. But most of the studies had been restricted to aquatic species therefore studies on terrestrial species are still rare. The scientific information on the potentially harmful effects of NPs severely lags behind the development of nanotechnologies. A wide variation has been found in all the toxicity studies reported in the literature, due to the different characteristics of nanoparticles like size distribution, crystal structure, morphology, agglomeration /dispersion, and dose/duration, as well as experimental designs. Particle size and surface area are important material characteristics from a toxicological perspective. As the size of a particle decreases, its surface area increases and also allows a greater proportion of its atoms or molecules to be displayed on the surface rather than the interior of the material. Therefore, it is essential to analyze the toxicity of nanoparticles in the context of their size for a comprehensive understanding of the adverse effects of nanoparticles. However, the toxicity of TiO2 and ZnO NPs in relation to their size remains yet to be understood.
However, recent studies have shown that TiO2 and ZnO NP exposure resulted in a size-dependent decrement in the growth, reproduction, and behavior of the different experimental model organisms even at the lowest concentration. The gene expression studies have shown that the toxicity of different TiO2 and ZnO NPs were mediated by inhibiting the Insulin/IGF- like signaling pathway.
By:
Dr. Priyanka Srivastava
Assistant Professor
School of Biosciences
