#titanium dioxide

Antibacterial coatings with short-term effect may fail over longer periods of time

Researchers from the Institute of Physics and the Institute of Molecular and Cell Biology of the University of Tartu have shown in a recently published study that antibacterial coatings which initially appear highly effective at destroying bacteria, may lose their performance over time. Therefore, long-term testing is essential for developing the best antibacterial materials. The article describing the results of the study, "Artificial aging induced changes in ZnO- and TiO₂-based polyacrylic surface coatings," was published in the journal npj Materials Degradation. Contamination of frequently touched surfaces with bacteria and other microorganisms is a major source of infectious disease outbreaks. Studies suggest that 40% of hospital-acquired infections may be spread specifically through contaminated surfaces. Therefore, coating these surfaces with light-activated, or photocatalytic, antibacterial coatings is a promising solution to reduce the spread of disease-causing bacteria.

Lasting Impression

Modern life is built on the hidden security of health and safety regulations. These oft-maligned but life-saving rules are founded on research into the risks and rewards of materials and practices. One current area of scrutiny is food-grade titanium dioxide – a white colourant used in foods and medicine. It's known to persist in dormant intestinal cells, but new research investigated if it lingers elsewhere in the body. When the team exposed colon cells and a mini gut model to everyday titanium dioxide levels, they found the particles (red in the gut sections pictured from mice fed without (top) or with (bottom) titanium dioxide) prevail inside active immune cells. However, these particles alone do not trigger inflammation, disturb cell activity, or impair immune function. Identifying where titanium dioxide accumulates and what it does will help assess real-world health risk, so we can trust that what we consume is safe.

Written by Anthony Lewis

Image from work by John W. Wills and colleagues

Department of Veterinary Medicine, University of Cambridge, Cambridge, UK

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, July 2025

Excerpt from this story from EcoWatch:

Mars – the company that owns Skittles – invites its customers to “taste the rainbow” when they tear open a package and pour some of the multi-colored candies into their mouths.  However, what they’re really tasting is titanium dioxide (TiO2).

Now, a class-action lawsuit filed in the U.S District Court for the Northern District of California Thursday argues that the coloring chemical is a “known toxin” that renders Skittles “unfit for human consumption,” as USA TODAY reported.

“Based on Defendant’s omissions, a reasonable consumer would expect that the Product can be safely purchased and consumed as marketed and sold,” the lawsuit read, as USA TODAY reported. “However, the Products are not safe and pose a significant health risk to unsuspecting consumers.”

TiO2 was approved by the Food and Drug Administration (FDA) for use in food in 1966, according to the Los Angeles Times. The U.S. agency still maintains that it’s safe to use as food coloring as long as no more than one percent of the weight of the food in question is added.

Astronomers at Penn State have used the Hubble Space Telescope to find a blistering-hot giant planet outside our solar system where the atmosphere "snows" titanium dioxide—the active ingredient in sunscreen. These Hubble observations are the first detections of this "snow-out" process, called a "cold trap," on an exoplanet. This discovery, and other observations made by the Penn State team, provide insight into the complexity of weather and atmospheric composition on exoplanets, and may someday be useful for gauging the habitability of Earth-size planets.