EFSA Pilot Project on NAMs for the hazard assessment of nanofibers. Lot 2: ‘Exploring the use of gut‐on‐a‐chip models for risk assessments of nanofibers’

The present project aimed to improve our understanding of potential effect of nanocellulose (NC) ingestion on human health, addressing some key objectives set by the European Food Safety Authority (EFSA). In particular, the use and improvement of not yet validated advanced in vitro models of human gut, both static and in tubular microfluidic format, was explored for assessing the interaction of the intestinal epithelium with nanocelluloses. NCs (nanofibers and nanocrystals) were examined as pristine material and upon exposure to digestive fluids and interaction with oro‐gastro‐intestinal enzymes. The NC local effects on the intestinal epithelium were assessed in terms of cytotoxicity, inflammation, and intestinal barrier integrity. Assessment of NC uptake and crossing of intestinal barrier was also explored. A specific focus was on immune reactivity at intestinal barrier site; the complex in vitro models were refined by complementation with primary innate immune cells. Exposure of intestinal tissues to inflammatory cytokines allowed to mimic the effect associated with disease condition and to address inflammation‐induced secondary toxicity.