Comparative transcriptomes of Caco-2 cells cultured under dynamic and static conditions following exposure to titanium dioxide and zinc oxide nanomaterials

Due to the widespread application of food-relevant inorganic nanomaterials, the gastrointestinal tract is potentially exposed to these materials. Gut-on-chip in vitro model systems are proposed for the investigation of compound toxicity as they better recapitulate the in vivo human intestinal environment than static models, due to the added shear stresses associated with the flow of medium in line with what cells experience in vivo. We aimed to compare the cellular responses of intestinal epithelial Caco-2 cells at the gene expression level upon TiO2 (E171) and ZnO (NM110) nanomaterial exposure when cultured under dynamic and static conditions. For this, we applied whole genome transcriptome analyses. Differentially expressed genes and related biological processes revealed culture condition specific responses upon exposure to TiO2 and ZnO nanomaterials. The materials had more effects on cells cultured in the gut-on-chip when compared to the static model, indicating that shear stress might be a major factor in cell susceptibility. This is the first report on application of a gut-on-chip system to evaluate cellular responses upon TiO2 and ZnO nanomaterials compared to a static system and extends current knowledge on nanomaterial-cell interactions and toxicity assessment. Dynamically cultured cells appear to be more sensitive and the gut-on-chip might thus be an attractive model to be used more extensively in the toxicological hazard characterization. Microarray analysis was performed on Caco-2 cells that were exposed to TiO2 or ZnO for 6hrs after being cultured statically or in a gut-on-chip device for 21 days.