Food additives and gut health: new research from the University of Sydney

The team of Professor Wojciech Chrzanowski in the Sydney Pharmacy School at the University of Sydney have published their findings on the toxic effect of titanium nanoparticles found in food. The paper “Impact of nano-titanium dioxide extracted from food products on Caco-2 cells using three-phase digestion model” was recently published in Environmental Science Nano.

TiO₂ particles have already been banned as food additives in the EU, and the group’s work serves to highlight the effects that they may be having on the gastro-intestinal tract. The authors explained their choice of cell model for the experiments; “Caco-2 cells were used as a basic model of the intestinal epithelial barrier in our studies, given their common use as the ‘gold standard’ for basic models of the GIT route of exposure in toxicological risk assessment”.

High-resolution imaging revealed cell stress

The TiO₂ nanoparticles’ effect on cell morphology was revealed by Nanolive’s high-resolution imaging. Images revealed that treated cells exhibited stress in the 72-hour imaging period, visible as the loss of tight junctions, cell rounding, shedding of the cell membrane, and signs of autophagy (Figure 1).

Figure 1. TiO₂ nanoparticle effects on cellular morphology. Untreated Caco-2 cells (left) exhibit normal morphology including an intact plasma membrane and tight junctions between cells. 72 hours after TiO₂ treatment, signs of cell stress were visible, including loss of tight junctions, and appearance of focal adhesions and signs of autophagy.

Can fluorescence signal problems be caused by metal nanoparticles?

Interestingly, a standard CCK-8 cytotoxicity assay reported that cell viability was not affected by TiO₂ treatment, in contrast to the results from the live imaging. Metabolic analysis of ROS using a fluorescence reporter assay also did not detect oxidative stress induced by TiO₂ treatment. The authors anticipate this was due to quenching of the fluorescence signal which has been reported for other metallic particles, a subject that still needs to be explored further. If Nanolive’s label-free imaging had not been used, it is likely that the harmful effect of the particles would have been missed.

Long-term Nanolive users

This paper is just the latest from this group, as they have been using Nanolive since 2016, and have previously published five other papers using Nanolive imaging. As Professor Chrzanowski said, “We love the Nanolive system and use it every day for every project!”

To look at the group’s work on microparticles in lung cancer, see: https://doi.org/10.1016/j.msec.2020.110801

To read their most recent paper: https://pubs.rsc.org/en/content/articlepdf/2023/en/d3en00549f

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