Dr. Otto Creutzenberg

“It seemed exciting to me to be involved in important studies that really help to evaluate the hazards from substances and ultimately minimize the risk to human health,” says Dr. Otto Creutzenberg. He is heading the Department of Inhalation Toxicology and has been involved in or even managed numerous toxicology studies. The results have been taken into account by the DFG Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, also known as MAK Commission, in the derivation of limit values and thus support the safe handling of these substances at workplaces.

It was in 1985, directly after completion of his doctorate, that the chemist embarked upon his first project at the Fraunhofer institute in Hannover – at that time called ITA, today ITEM –  in Prof. Muhle's working group: a study on the lung toxicity of toners. The aim of this large industrial project with a contract volume of eight million deutschmarks was to find out whether toner dust and particles pose a similar occupational health risk as was already known for diesel exhaust fumes and particulate matter generated in the mining industry.

Dr. Creutzenberg already took courses in toxicology while he was a student at the University of Münster and he did his doctorate in biochemistry, a subject that was more multifaceted than the chemical synthesis of substances. His interest has always been in living things rather than in plain material science. It was in the early 2000s that the toxicologist truly broke new ground with the Fraunhofer team. The industrial production of nanomaterials experienced a real boom at that time. After all, tiny amounts of these materials were sufficient to achieve the desired effects. In addition, they had special, new features and capabilities and could be used for a broad range of applications. It was still unknown, however, whether nanomaterials might pose a greater risk to humans and the environment than traditional micro-sized particulate matter. “They definitely have the potential to do so: because of their special characteristics, such as their tininess, their large specific surface area and their high reactivity in some cases – but also because of their diverse application areas and high production volumes,” explains Dr. Creutzenberg.

Over the years, he has worked on a variety of projects investigating nanomaterials, for example carbon nanotubes, which due to their length and fiber-like structure are suspected to have a similar toxic potential as asbestos fibers. Another project aimed to verify whether the OECD guidelines for micro-scale particulate matter that were valid at the time could also be applied to nanoparticles, such as amorphous silica and zinc oxide particles, or whether amendments were required. Furthermore, together with other Fraunhofer ITEM working groups, he established models to enable testing of modified and well-characterized carbon nanoparticles (e.g. graphene) for toxic effects in the lungs and airways – from simple cell cultures to tissue culture models and validation in animal models.

Dr. Creutzenberg has always been intrigued by the Fraunhofer system: “As a researcher, I have much freedom in my work and it's exciting to find a way to make a project happen and get funding for it.” The scientist has always found such a way, even if he had to travel halfway around the world to win customers from Japan. The experiences he was able to make on these occasions have become lasting impressions for him.