Loads of cosmetics like sunscreen lotions contain titanium dioxide. These nanoparticles are contentious. Experts suspect they may have harmful effects on people and the environment. But it is difficult to prove that the particles are in the lotions. Using a method developed by Fraunhofer researchers, the particles can now be calculated.
Cosmetics increasingly contain nanoparticles. One especially sensitive issue is the use of the minuscule particles in cosmetics, since the consumer comes into direct contact with the products. Sunscreen lotions for example have nanoparticles of titanium oxide. They provide UV protection: like a film made of infinite tiny mirrors, they are applied to the skin and reflect UV rays. But these tiny particles are controversial.
They can penetrate the skin if there is an injury, and trigger an inflammatory reaction. Its use in spray-on sunscreens is also problematic. Scientists fear that the particles could have a detrimental effect on the lungs when inhaled.
Even the effect on the environment has not yet been adequately researched. Studies indicate that the titanium oxide which has seeped into public beaches through sunscreens can endanger environmental balance. Therefore, a labeling requirement has been in force since July 2013, based on an EU Directive on cosmetics and body care products.
If nano-sized ingredients are used in a product, the manufacturer must make this fact clear by adding “nano-” to the listed ingredient name. Due to requirements imposed by the legislature, the need for analysis methods is huge.
Determining particle sizes down to the tiniest scale
Today’s electron microscope imaging processes, such as transmission-electron microscopy or scanning electron microscopy, are based on the properties of light dispersion. They are used to detect all particles present. They do not differentiate between a cell, a nanoparticle – or a piece of lint. These methods are ideally suited for the study of surface properties and shapes.
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