Research on ultrafine particles has laid the foundation for the emerging field of nanotoxicology, with the goal of studying the biokinetics of engineered nanomaterials and their potential for causing adverse effects. Most reports find that ultrafine particles are more toxic than equivalent larger-sized particles of a given material at similar doses per gram of body weight. A mite next to a gear chain produced using nanotechnology Nanotechnology as a collective term refers to technological developments on the nanometer scale, usually 0. ...

Assessing the safety of engineered nanoparticles is a highly complex matter that goes beyond traditional toxicology. Engineered nanoparticles are not a uniform group of substances. The problem arises from the fact that particle size alone (which determines the surface area of a given mass of a substance) is not the only factor that determines the toxicological impact of a material and that makes nanoparticles of a given substance behave differently from the bulk form. Very Basic Description A nanoparticle is a microscopic particle whose size is measured in nanometers. ... Toxicology (from the Greek words toxicos and logos [1]) is the study of the adverse effects of chemicals on living organisms [2]. It is the study of symptoms, mechanisms, treatments and detection of poisoning, especially the poisoning of people. ...

While the release and production of nanoparticles during industrial and combustion processes and activities is mostly unintentional, the emergence of nanotechnological production processes introduces the intentional and controlled manufacture of nanoparticles. The latter can be further differentiated as either bulk nanoparticles in industry, e.g., carbon black or titanium dioxide, or so-called engineered nanoparticles, e.g., carbon nanotubes. Carbon black is a material produced by the incomplete combustion of petroleum products. ... An electronic device known as a diode can be formed by joining two nanoscale carbon tubes with different electronic properties. ...

Given the prospects for nanotechnology, and the fact that products containing engineered nanoparticles have already been introduced to the marketplace, the increasing flow of new products will bring about the massive production of engineered nanoparticles. Molecular gears from a NASA computer simulation. ...

Despite all the scientific knowledge gained in the toxicology of particulate matter, because of the many variables involved, scientists still cannot accurately predict how nanomaterials will affect living organisms. What is clear, though, is that the biologic activity and biokinetics of nanoparticles are different from larger particles, and that they depend on many parameters. These parameters can modify cellular uptake, protein binding, translocation from portal of entry to target site, and the possibility of tissue injury.

Important from a toxicological point of view are the physiochemical properties that come with size and lead to certain biological reactivity. Size, together with differences in shape, surface structure, chemical composition (purity, crystallinity, electrical properties, etc.), solubility and biopersistence make for a large number of variables that need to be considered when assessing nanoparticles. On top of that, powders or liquids containing nanoparticles are almost never monodisperse but contain a range of particle sizes. This complicates experimental analysis as larger nanoparticles might have different properties than smaller ones. Also, nanoparticles show a tendency to aggregate and such aggregates often behave differently from individual nanoparticles.

Most, if not all, toxicological studies on nanoparticles rely on current methods, practices and terminology as gained and applied in the analysis of micro- and ultrafine particles and mineral fibers. Together with recent studies on nanoparticles, this provides an initial basis for evaluating the primary issues in a risk assessment framework for nanomaterials.

Given the many parameters involved, nanotoxicology requires an interdisciplinary team approach, even more so than classical toxicology, in order to arrive at an appropriate risk assessment.

As a still-maturing science, nanotoxicology will expand the boundaries of traditional toxicology from a testing and auxiliary science to a new discipline where toxicological knowledge of nanomaterials can be put to constructive use in therapeutics as well as the development of new and better biocompatible materials.

Further Reading

• [1] Oberdörster G: Nanotoxicology: An Emerging Discipline Evolving from Studies of Ultrafine Particles.
• [2] Nel A: Toxic Potential of Materials at the Nanolevel.
• [3]| Kurath M: Toxicology as a nanoscience? – Disciplinary identities reconsidered.
• [4] Berger M: Toxicology - from coal mines to nanotechnology.