Because of their small size, nanoparticles may have unique physical and chemical properties. These properties may cause them to interact with living systems differently than larger materials with the same chemical composition (also known as bulk materials).

However, since it’s photosensitive — meaning it can stimulate free radical production — it’s usually coated in silica or alumina to prevent potential cell damage without reducing its UV-protective properties (7Trusted Source).

What Is Titanium Dioxide?
Titanium dioxide, also called titania, is an odorless white powder and naturally occurring mineral that is widely used as a pigment for its brightness and whitening effects on a variety of materials, such as paint, plastic, paper, cosmetics, sunscreens, toothpastes and foods.
It’s produced through the sulfate or chloride process, which both involve treating titanium ore with sulfuric or hydrochloric acid to produce titanium sulfate or titanium chloride. These materials are then further processed to remove impurities and produce titanium dioxide in its final form.
Food-grade titanium dioxide differs from what’s added to plastics and paints to enhance whiteness. However, there have been concerns about the environmental impact of titanium dioxide production and the potential health risks from exposure to its particles.
Although food-grade titanium dioxide must be 99 percent pure, there’s still a risk of it containing potential contaminants, such as mercury, lead and arsenic. Additionally, inhaling the mineral over time can possibly cause it to build up in your body, leading to adverse effects.
Uses