Nanotechnology

by

Anupam Dhasmana, Sumbul Firdaus, Mohtashim Lohani, Mohammed Yahya Areeshi, Peter Langer, Qamar Rahman

• LAST REVIEWED: 28 November 2016
• LAST MODIFIED: 28 November 2016
• DOI: 10.1093/obo/9780199756797-0154

Introduction

Nanotechnology is defined as the study of structures of size ranging between 1 and 100 nanometers in at least one of their dimensions. It is an emerging interdisciplinary field of research and development, integrating multiple areas of science such as chemistry, engineering, physical sciences, molecular engineering, biology, and biotechnology. Nanotechnology is the design, production, characterization, and application of structures, devices, and systems by controlling shape and size at nanometer scale. These structures of the nanometer range, with novel properties and functions, are termed as nanoparticles (NPs). Nanoparticles may be dry, suspended in a gas (nanoaerosol), suspended in a liquid (as a nanocolloid or nanohydrosol), or embedded in a matrix (as a nanocomposite). Nanoparticles exist in several forms, such as nanotubes, nanoplates, and nanofibers. Nanoparticles are predicted to play a significant role in medical science and technology in the coming decades due to their special electronic, mechanical, and chemical properties. The applications of NPs for drug delivery, pharmaceutical, and many industrial and commercial practices are expected to increase considerably. Out of surplus of size-dependent physical properties of nanomaterials, these unlimited advantages of nanoparticles lead to their mass production, making exposure to them unavoidable. Human exposure to these nanoparticles raises alarm about their potential risk to human health. The influence of nanosciences and technology has been expanded from their medical, technological, industrial, and environmental applications to fields such as engineering, biology, chemistry, materials science, and communications. The presence of nanoparticles is not in itself a threat, but nanoparticles have the ability to harm human and other life by interacting through various mechanisms. It is only certain aspects that can make them risky—in particular, their mobility and their increased reactivity. In addition, various strict guidelines are required regarding which defensive measures are warranted in order to support the improvement of “green nanosciences and technologies” and other potential modern technologies, while at the same time reducing the potential for negative unexpected consequences in the form of unfavorable effects on human and environmental health.

Sources of Nanoparticles

Nanoparticles are defined as materials with at least one dimension in the 1–100-nanometer (nm) range and may be naturally present in the atmosphere in the form of some viral particles and proteins or as byproducts of photochemical and volcanic activities. Nanoparticles may be manufactured/engineered intentionally, or they may be unintentionally produced anthropogenically via engine exhaust (Smita, et al. 2012). They may be used for various purposes, such as a catalyst in chemistry, as drug delivery devices in nanobiotechnology, or as imaging agents and consumer products. They are also used in engineering and information technology (Aguilera-Granja, et al. 1993). The utility of nanoparticles has increased in almost every field due to their enhanced size-dependent properties as compared to larger particles of the same material. Electrical, optical, and chemical properties are very different at “nano” scale as compared to those exhibited by larger particles; a maximum number of nanomaterial atoms are at the surface, and, due to this very high reactivity, nanoparticles are used in decontamination and detoxification (Deng, et al. 2011). Large-scale materials have a lower percentage of atoms at the surface.

• Aguilera-Granja, Faustino, Jesús Dorantes-Dávila, José L. Morán-López, and Juan Ortíz-Saavedra. 1993. Electronic structure of some semiconductor fullerenes. Nanostructured Materials 3.1–6: 469–477.

  DOI: 10.1016/0965-9773(93)90114-Q

  Fullerenes have useful properties in the material sciences, such as in nano-microscopic-engineered semiconductors.

• Deng, Qixin, Chaozhang Huang, Wei Xie, et al. 2011. Significant reduction of harmful compounds in tobacco smoke by the use of titanate nanosheets and nanotubes. Chemical Communications 47.21: 6153–6155.

  DOI: 10.1039/C1CC10794A

  Titanate nanosheets (TNS) and titanate nanotubes (TNT) have also been synthesized and used as additives for removing harmful compounds from cigarette smoke.

• Smita, Suchi, Shailendra K. Gupta, Alena Bartonova, Maria Dusinska, Arno C. Gutleb, and Qamar Rahman. 2012. Nanoparticles in the environment: Assessment using the causal diagram approach. Environmental Health 11.S1: S13.

  DOI: 10.1186/1476-069X-11

  Man-made engineered nanoparticles (ENPs) are unknowingly or purposely released in the environment during various industrial and mechanical processes. In the fireplace at home, fullerenes such as buckyballs or buckytubes are formed when wood is burned. In industrial processes, coal, oil, and gas boilers release tons of nanoparticles unintentionally.