Nanotechnology: Toxicologic Pathology

Abstract

Nanotechnology involves technology, science, and engineering in dimensions less than 100 nm. A virtually infinite number of potential nanoscale products can be produced from many different molecules and their combinations. The exponentially increasing number of nanoscale products will solve critical needs in engineering, science, and medicine. However, the virtually infinite number of potential nanotechnology products is a challenge for toxicologic pathologists. Because of their size, nanoparticulates can have therapeutic and toxic effects distinct from micron-sized particulates of the same composition. In the nanoscale, distinct intercellular and intracellular translocation pathways may provide a different distribution than that obtained by micron-sized particulates. Nanoparticulates interact with subcellular structures including microtubules, actin filaments, centrosomes, and chromatin; interactions that may be facilitated in the nanoscale. Features that distinguish nanoparticulates from fine particulates include increased surface area per unit mass and quantum effects. In addition, some nanotechnology products, including the fullerenes, have a novel and reactive surface. Augmented microscopic procedures including enhanced dark-field imaging, immunofluorescence, field-emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy are useful when evaluating nanoparticulate toxicologic pathology. Thus, the pathology assessment is facilitated by understanding the unique features at the nanoscale and the tools that can assist in evaluating nanotoxicology studies.

Extrapulmonary transport of MWCNT following inhalation exposure

“…Detection and quantitiatve assessment of other nanoparticles has been reported. These include the diesel fuel catalyst, cerium oxide [23], titanium dioxide nanospheres [24], titanium dioxide nanospheres and nanobelts [25] and summarized in a review article on pathologic assessment of nanoparticles which describes aspects of enhanced darkfield in nanoparticle detection [43]. …”

Long-term effects of carbon containing engineered nanomaterials and asbestos in the lung: one year postexposure comparisons

“…Unmasked histopathology assessment was used because unmasked evaluation is generally accepted as the most accurate method for evaluating the toxicological histopathology of new agents and because deposition of SWCNT, CNF, and asbestos are visible in tissue section, making masked evaluation impossible because exposure status is apparent during the evaluation (14). SWCNT, CNF, and asbestos were visible in light microscopic sections, and their location in cells could be identified because of their ability to strongly absorb light (25,28). The identity of SWCNT, CNF, and asbestos in tissue section was confirmed by their presence only in the group exposed to the specific test article and by comparison with the distinctive microscopic appearance of each test article before exposure.…”

Assessment of food toxicology

“…The discipline of environmental toxicology is related to studies of various chemical, biological and physical agents which are harmful to humans, whereas regulatory toxicology is concerned with risk assessment of food and potential toxicants [51,162]. By virtue of advances in nanotechnology and its application in food industry, the newly created discipline of nanotoxicology investigates safety or potential hazards of nanoparticles [52,[163][164][165]. Another dimension refers to genetically modified organisms (GMO) or food (GM) as potential source of toxicity [52,166,167].…”