Investigating ingested nanomaterials’ safety – the case of TiO2 and innovative nanocelluloses.

Vital, Nádia; Silva, Maria João; Louro, Henriqueta

http://hdl.handle.net/10400.18/9116

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Authors

Vital, Nádia

Silva, Maria João

Louro, Henriqueta

Abstract(s)

Introduction: The development of nanomaterials(NMs)-based technologies led to their increased use in key sectors and products related to food, food contact materials and feed. Many available products have NMs, as intentional constituents or contaminants from process ou food packaging release, such as silicon or titanium dioxide(TiO2) NMs. Others are being developed, like nanocelluloses(CNMs; doi:10.3390/nano12193375). However, it is recognised that the NMs’ specific physicochemical properties, conferring them unique benefi cial characteristics, can also elicit nano-bio interactions leading to toxic potential. Also, their dynamic behaviour in the surrounding matrix, may lead to secondary features determining the toxicological outcomes. Recognizing that processes like intake or digestion may modify the NMs’ characteristics leading to unexpected toxicity in human cells, EFSA included the use of in vitro digestion models in their specific guidelines concerning risk assessment of nanomaterials for food and feed(DOI:10.2903/j.efsa.2021.6768). Methodology: With the aim to contribute to the safety assessment of NMs, intestinal cell models (Caco-2 and HT29-MTX-E12 cells) were exposed to TiO2 NMs or innovative CNMs. Additionally, samples submitted previously to in vitro simulation of human digestion were used, and the genotoxicity(comet and micronucleus assays) was investigated with and without the digestion process. Results: After TiO2 NMs’ exposure, the micronucleus assay, an indicator of cancer risk, suggested eff ects on the chromosomal integrity in the HT29-MTX-E12 cells, for all the tested TiO2 NMs, especially after the in vitro digestion. Upon exposure to the two CNMs, no chromosomal damage was observed in the micronucleus assay, but the comet assay revealed DNA damage in the same cells, after 3h and 24h exposure, an effect slightly more relevant after the digestion of the cellulose nanofibril. Conclusion: Overall, the results show diff erent outcomes when using different NMs, and with/without digestion. Thus, it is important to consider the primary and secondary NMs’ characteristics determining the adverse eff ects, taking into account the human digestion for nanosafety assessment.

Description

Thanks to P. Ferreira, J.Pedrosa (University of Coimbra) and A.F.Lourenço (RAIZ) for the CMNs; to P.Alvito, R.Assunção, M.Silva (Food Safety Department, INSA) for in vitro digestion.