Lichtgedanken 04

Rubrik 52 To paraphrase a German saying: you eat with your eyes. That is why food manu- facturers often pull off a range of tricks to make their products as visibly appeal- ing as possible for consumers. Silicon or titanium dioxide are, for example, used to ensure that ketchup flows smoothly out of the bottle, that colourful choco­ late buttons shine appealingly and that instant cappuccino powder doesn’t clump together in the packaging. These substances form fine powders, which lend the foodstuffs their desired prop- erties. The problem: the powders are so fine that—depending on the manu- facturer—they always contain a certain amount of minute nanoparticles. Nanoparticles measure only a few nano- metres in size and are thus smaller than most molecules that our body deals with. »If nanoparticles end up in the hu- man digestive system through our diet, they can, due to their tiny size, pass through the intestinal wall and spread practically all over the body«, says Dr Thomas Schneider from the Institute of Nutritional Sciences at the University of Jena. »Despite this, no one can currently say with any certainty whether these particles are harmful or what health risks they actually pose.« According to the nutritional toxicologist, the study has been extremely inconsistent to date. This is largely due to the inadequate test methods and the lack of opportunity to show that there are nanoparticles in the body and to characterize them. Analysis platform to detect potentially harmful nanomaterials in foodstuffs In order to change this situation, Thomas Schneider and his colleague Prof. Dr Mi- chael Glei have grouped together with a partner from the industry, Analytik Jena AG, to launch a research project. The new joint project »Analyse von synthet- ischen Nanopartikeln in Lebensmitteln mittels Einzelpartikel-ICP-MS« (Ana- lysis of synthetic nanoparticles in food- stuffs using single particle-ICP-MS) is being funded for two and a half years by the state of Thuringia using funds from the European Regional Development Fund to a sum of 615,000 euros. Around 285,000 euros of this funding will go to the University of Jena. The aim of the project is to develop an analysis platform to detect potentially harmful nanomaterials in foodstuffs. The researcherswant to utilise the highly sensitive process of inductively coupled plasma mass spectrometry (ICP-MS) for this purpose. »This analysis procedure can be used to detect even the smallest traces of metals, such as titanium, gold or magnesium«, explains Dr Schneider. In order to utilize the method for the analysis of nanoparticles in foodstuffs, the researchers must first develop a spe- cial sample supply system and some data analysis software. »In addition to this, we also want to gauge the toxicological properties of the nanoparticles«, states Prof. Glei. The particles are tested on cell cultures in his laboratory. This test shows whether and to what degree they affect the growth of the cells and whether they lead to da­ mage, for example with regard to DNA. Bowel cell cultures are used to model the natural barrier of the human diges­ tive tract. Tiny and useful—and harmless? Nutritional scientists at Jena want to trace nanoparticles in foodstuffs. The aim of the project, which is funded by the EU and the state of Thuringia, is to be able to properly assess the risk potential of nanoma- terials in foodstuffs. BY UTE SCHÖNFELDER As part of a new project, Dr Thomas Schneider is synthesizing and characterizing nanoparticles—here he presents solutions with nanospheres made of gold (left) and silver.