Page 240 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

Principles and Procedures to Assess Nanomaterial Toxicity 225

Online Data Bank
With an increasing number of NM being produced, it is essential that
the scientific community have an easily accessible data bank. This online
bank should hold safety information of all NM already tested and provide
frequent updates on NM in the process of being tested. This format is
already in use by the Hazardous Substances Data Bank (HSDB), which
can be accessed at www.nlm.nih.gov/pubs/factsheets/hsdbfs.html. Another
example is the protein data bank (PDB) found at www.rcsb.org/pdb. With
these formats in mind, many different modes of information about NM,
such as NM characterization, laboratory methods, environmental
fate/exposure, safety and handling, in vitro studies, in vivo studies, and
human health effects, can be provided to the interested party. This type
of data bank promotes standardization and allows open access to up-to-
date information. It is essential that we use these methods when com-
municating with a worldwide audience, especially given the rapid growth
in the number of new NM.
Once a NM database has been established, the scientific community
can further refine the material characteristics leading to toxicity (e.g.,
size/charge or hydrophobicity). It will also be possible to work with
batches of NM to develop a toxicological grading system.
In summary, the demand for a predictive and pragmatic approach to
nanotoxicity is compelling. While it is optimal to collect data at differ-
ent tiers of toxicity, some flexibility is required to develop decision
matrixes for in vitro and in vivo testing. Ultimately, the goal of the pre-
dictive approach would be to develop a series of toxicity assays that limit
the demand for large-scale in vivo studies, both from a cost as well as
an animal-use perspective. It is important to mention the potential
significant difficulties that may be encountered in conducting in vitro
and in vivo studies with engineered NM. This has largely to do with lack
of knowledge of real-world exposures to NM, including dosage, com-
plexity of working/living environment, aggregation status, and so on.
As nanotechnology develops, it is essential that the toxicological
approach also evolves and stays up to date. This will provide an impor-
tant safeguard for the continued expansion of the nanotechnology
industry.

Abbreviations
ARE, antioxidant response element; ESR, electron spin resonance;
GPx, glutathione peroxidese; GSH, glutathione; GSSG, glutathione
disulfide; GST, glutathione S-transferase; JNK, NH -terminal Jun
2
kinase; HO-1, heme oxygenase 1; MAPK, mitogen-activated protein
–
kinase; NAC, N-acetylcysteine; O , superoxide; OH, hydroxyl radical;
2
PM, particle matter; PT, permeability transition; ROS, reactive oxygen