Toxicity Testing of Nanomaterials

Abstract

The large-scale production and consumer exposure to a variety of nanotechnology innovations has stirred interest concerning the health consequences of human exposure to nanomaterials. In order to investigate these questions, in vitro systems are used to rapidly and inexpensively predict the effects of nanomaterials at the cellular level. Recent advances in the toxicity testing of nanomaterials are beginning to shed light on the characteristics, uptake and mechanisms of their toxicity in a variety of cell types. Once the nanomaterials have been satisfactorily characterized, the evaluation of their interactions with cells can be studied with microscopy and biochemical assays. The combination of viability testing, observation of morphology and the generation of oxidative stress provide clues to the mechanisms of nanomaterial toxicity. The results of these studies are used to better understand how the size, chemical composition, shape and functionalization may contribute to their toxicity. This chapter will introduce the reader to the impact of nanomaterials in the workplace and marketplace with an emphasis on carbon-based and metal-based nanomaterials, which are most commonly encountered. While most purified carbon nanomaterials were nontoxic to many cell lines, many metal nanoparticles (e.g., silver or manganese) were more toxic. Other side- effects of nanoparticle interactions with cells can also occur, such as increased branching and dopamine depletion. Further investigation into the characteristics, uptake and mechanisms of nanomaterial toxicity will continue to elucidate this fascinating and rapidly growing area of science.

Assessing nanoparticle toxicity in cell-based assays: influence of cell culture parameters and optimized models for bridging the in vitro–in vivo gap

“…Given the ever increasing use of NP in technological applications and everyday consumer goods and the high interest of exploiting the exceptional features of the NP in biomedical applications, it is expected that both intentional and unintentional exposure will become more frequent 4,5 . Because of this, the increase in nanotechnology implementation in our daily lives is joined with the raising of concerns on potential adverse effects towards human health 6 .…”

“…Because of this, the increase in nanotechnology implementation in our daily lives is joined with the raising of concerns on potential adverse effects towards human health 6 . It is therefore recommended that the safety of these products, towards consumers and especially towards workers at the production site, is carefully evaluated before its introduction to the market 4,5,7 . However, there are currently only very limited regulations on the use and the safety criteria for nanomaterials in industrial applications or consumer goods.…”

Nanotoxicity: emerging concerns regarding nanomaterial safety and occupational hard metal (WC-Co) nanoparticle exposure

“…The term ENM broadly encompasses a number of nano-sized materials that vary in shape, such as nanotubes, nanowires, or nanoparticles (NPs), which are generally defined as "any material having at least one dimension smaller than 100 nm." 1 Because of their extremely small size and high surface area, NPs offer a number of advantages over traditional "bulk" materials and are suitable for a wide variety of applications in consumer goods, 2,3 medical devices and diagnostics, [4][5][6] pharmaceutical products, 4,7-10 fuel additives, 11,12 and other industrial uses. [13][14][15][16][17] As a result, the number of manufactured goods containing NPs is continually rising; in 2006, manufacturers reported that NPs were incorporated in over 600 consumer products worth $50 billion in market value, 18 a number which has doubled to .1,600 NP-containing consumer products in 2013.…”

“…Primary effects resulting from direct cellular NP contact may include toxicity, oxidative stress, DNA damage, and inflammation. 1,28,29 Because of their small size, NPs may translocate through tissue barriers into the blood, where they can circulate and eventually deposit in other organs, thereby generating a secondary NP exposure. Secondary effects may include toxicity at the site of NP deposition, in organs such as the liver, spleen, or kidneys, stimulation of systemic inflammation or alterations in systemic function.…”

“…Secondary effects may include toxicity at the site of NP deposition, in organs such as the liver, spleen, or kidneys, stimulation of systemic inflammation or alterations in systemic function. 1,[28][29][30] The first three routes of exposure occur through external NP sources, but there is emerging evidence which indicates that humans may also be exposed internally, when orthopedic or surgical implant wear NPs are released locally from the implant site. 23,31,32 Most commonly, humans are exposed to NPs in their environments through the pulmonary route, by inhaling airborne NPs during normal breathing.…”