Enhanced Uptake of Fe₃O₄ Nanoparticles by Intestinal Epithelial Cells in a State of Inflammation

Fe₃O₄ nanoparticles (Fe₃O₄ NPs) have been used for medical and drug applications, although the mechanisms of cellular uptake and transport need to be further evaluated under inflammatory conditions. In the present study, we investigated the uptake of Fe₃O₄ NPs (20, 50, 100, and 200 nm) by intestinal epithelial cells under inflammatory conditions via the light scattering of flow cytometry and inductively coupled plasma mass spectrometry (ICP-MS) techniques. The results of the correlation analysis indicated that the uptake ratios of Fe₃O₄ NPs by intestinal epithelial cells under inflammatory conditions were higher than those under the control conditions. The transportation ratios of NPs by inflammatory Caco-2 cells increased almost 0.8-1.2 fold compared to the control. The internalization of the Fe₃O₄ NPs in Caco-2 cells was mediated by clathrin-related routes in both the control and an interleukin-1β (IL-1β)-induced inflammatory condition. The level of mRNA of clathrin expressed in Caco-2 cells that were stimulated by IL-1β was almost three times more than the control. Consistently with the mRNA expression, the level of protein in the clathrin was upregulated. Additionally, it was verified for the first time that the expression of clathrin was upregulated in IL-1β-stimulated Caco-2 cells. Collectively, these results provided a further potential understanding about the mechanism of Fe₃O₄ NPs' uptake by intestinal epithelial cells under inflammatory conditions.