BIOKINETICS AND EFFECTS OF NANOPARTICLES (p. 15)
GUNTER OBERDÖRSTER
University of Rochester School of Medicine and Dentistry,
Department of Environmental Medicine, 575 Elmwood Avenue,
MRBx Building, Box 850, Rochester, New York 14642, USA
Abstract:
Exposures to airborne nanosized particles (<,100 nm) have been experienced by humans throughout their evolutionary stages. Recently, the rapidly developing field of nanotechnology is likely to become yet another source for human exposures to nanosized particles– engineered nanoparticles (NPs)– by different routes, i.e., inhalation, ingestion, dermal, or even injection.
Nanotechnology is defined as research and technology development at the atomic, molecular, or macromolecular levels, in the length scale of ~1–100 nm range. One of the many promising applications of engineered NPs is in the area of medicine, for example, targeted drug delivery as aerosols and to tissues which are difficult to reach.
The discipline of nanomedicine has arisen to develop, test, and optimize these applications. However, the same properties that makes NP attractive for development in nanomedicine and for specific industrial processes could also prove deleterious when NP interact with cells. An emerging discipline– nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices– is gaining increased attention.
Nanotoxicology research will not only provide information for risk assessment of NP based on data for hazard identification, dose–response relationships, and biokinetics, but will also help to advance further the field of nanomedicine by providing information to alter undesirable NP properties.
Although potential adverse effects of engineered NP have not been systema- tically investigated, there are a number of studies in the area of inhalation toxicology and also human epidemiology from which some preliminary some decades-old– mostly forgotten– studies with nanosized particles which shed light on the biokinetics of such particles once introduced into the organism.
This presentation summarizes results of studies with nanosized particles with a focus on the respiratory tract and skin as portals of entry. conclusions about effects of nanosized particles can be drawn. There are also Examples of translocation and effects of nanosized particles and presumed consequences, on the other hand, the findings also give us ideas about the intriguing possibilities that NP offer for potential use as diagnostic tools or as therapeutic delivery systems.
A thorough evaluation of desirable versus adverse effects is required for the safe use of engineered NP, and major challenges lie ahead to answer key questions of nanotoxicology, foremost being the assessment of human and environmental exposure, the identification of potential hazards (toxicity vs. benefit), and the biopersistence in cells and subcellular structures.
Results so far demonstrate that the highly desirable properties of nanoparticles, which makes them attractive as medicinal aerosols, as well as their potential to induce toxicity, depend not only on their size but on a variety of surface properties. To establish the principles which govern NP-cell interactions will be a major challenge for the field of Nanotoxicology.
1. Introduction
Exposures to airborne ultrafine particles (UFPs,<,100 nm) have been experienced by humans throughout their evolutionary stages, but it is only with the advent of the industrial revolution that such exposures have increased dramatically because of anthropogenic sources such as internal combustion engines, power plants, and many other sources of thermodegradation. |
