CESAM work on TiO2 nanomaterials in the journal Nanoscale
Published in 14/11/2018
Mónica Amorim, researcher of the Department of Biology and the Centre for Environmental and Marine Studies (CESAM), from the research group of Ecology and applied Ecotoxicology - applEE, coordinated by Prof. Amadeu Soares, co-authored a paper published in Nanoscale journal: “Mechanisms of (photo)toxicity of TiO2 nanomaterials (NM103, NM104, NM105): using high-throughput gene expression in Enchytraeus crypticus”. Titanium dioxide (TiO2) nanomaterials (NMs) are among the most highly produced worldwide, estimates are around 60.000 tonnes per year. The applications go from the common use as sunscreens (UV protectors) to photocatalytic properties for soil remediation. The effects of NMs in the environment are assessed using methods available in the legislation for the evaluation of substances (REACH: Registration, Evaluation, Authorization and Restriction of Chemicals), via the effect assessment of physiological endpoints in organisms, e.g. survival and reproduction in invertebrates. However, the assessment of the mechanisms of action of NMs and (sub-)cellular effects that precede the effects observed in the organisms is very important, since it may allow to earlier assess, as well as to potentiate the production of safer NMs for the environment (safety-by-design). Hence, the development of techniques and methods that allow to explore the mechanistic effects, is a priority. This is precisely what was shown in the recently published article in Nanoscale, where a 44000 genes microarray was explored, a tool developed by UA team for a model species in ecotoxicology. "High-throughput gene expression was used to assess the molecular mechanisms, while also anchoring it to known effects at the organism level (i.e., reproduction). Results showed that the photoactivity of TiO2 (UV exposed) played a major role in enhancing TiO2 toxicity, activating transcription of oxidative stress, lysosome damage and apoptosis mechanisms. For non-UV activated TiO2, where toxicity at organism level (reproduction) was lower, results showed the potential for long-term effects (i.e., mutagenic and epigenetic)." The response to stress is usually activated, after a short period of time, in cells and with genetic precursors, hence representing the signalling of potential adverse effects that are apparent in the organism only later. The possibility to predict effects in an earlier stage is an aspect that deserves attention and has an enormous potential, this is one of the foccus of this research group. For further reading.
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