Christy
Haynes
University of Minnesota, Minneapolis, MN, USA. E-mail: chaynes@umn.edu
The breadth of fields represented in the 11 manuscripts that make up this themed issue is impressive, with contributions from analytical chemists, surface scientists, soil scientists, and freshwater biologists, among others. This is a tribute to the broad interest and highly multidisciplinary nature of the field of nanotoxicology. Similarly, the nanoparticle materials considered are broad, including Ag, Au, Ag/Au alloys, silica, titania, polymer, and carbon-based nanoparticles, among others. The methods employed for nanoparticle or toxicity analysis are also varied – some are traditional colloidal analysis methods whereas others are adapted from other fields. For example, Martin and co-workers used mid-infrared analysis (comparing attenuated total reflectance FT-IR to synchrotron radiation-based FT-IR) to examine the interaction between carbon-based nanomaterials and either Gram-negative or Gram-positive bacteria. The researchers found that the two different variations of FT-IR gave similar information and that, while there was some similarity among the biochemical signatures measured with varied materials, there were also some distinctions that may be useful as toxicity biomarkers. In another contribution, Bolea and co-workers used asymmetric field flow fractionation to help characterize Ag nanoparticle size, dissolution, and acquired protein corona in cell culture medium as they considered toxicity to cultured cells. In their contribution, Cohen and co-workers employ data mining techniques to examine results of a high-throughput nanotoxicity screen and find some clustering in the data that indicates convergence on particular biological pathways.
The model biological and ecological systems represented here are also widely varied, ranging from a model blood–brain barrier to bacteria to zebrafish embryos. In the latter model, Pedersen and colleagues showed the size-dependent phototoxicity of titania nanoparticles to zebrafish embryos, as evidenced by increased reactive oxygen species and DNA damage. To bookend the new experimental methods and results, this themed issue also includes a Minireview by Grassian and colleagues focused on using surface science spectroscopic analysis to characterize critical solid/liquid interfaces in nanotoxicity studies and a Critical Review by Klaper and colleagues about the newest methods in genotoxicity analysis. Clearly, there are a lot of exciting ways that advanced analytical methods are contributing to the field of nanoparticle toxicity, but many challenges remain, including the need for (1) dynamic, real-time monitoring of nanoparticle/biological interactions and nanoparticle coronas within both biological and ecological matrices, (2) methods to detect engineered nanoparticles at the concentrations currently present in the environment, and (3) models that predict nanoparticle exposure levels and nanoparticle toxicity based on the input nanoparticle material, size, shape, and surface chemistry. Hopefully, these critical advances in the field of nanotoxicity will build on those published in this themed collection and will soon appear in future Analyst issues.
Christy Haynes, University of Minnesota, Minneapolis, MN, USA
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