Having a laser printer right next to your workstation is certainly very practical. That being said, there is the risk that these machines, just like 3D printers, could emit aerosols during operation that contain, among other things, nanoparticles – particles that are between one and one hundred nanometers in size. By comparison, one hair is about 60,000 to 80,000 nanometers thick. Nanoparticles are also produced by passing road vehicles, for example, through the abrasion of tires. As yet, however, little is known about how these particles affect the human body when they are inhaled into the lungs. Until now, the only way to study this would have been by animal testing. What’s more, large sample quantities of the relevant aerosol would have to be
collected at great expense.
Directly measurable biological impact
Researchers from the Fraunhofer Institute for Toxicology and Experimental Medicine ITEM and the Fraunhofer Institute for Algorithms and Scientific Computing SCAI are collaborating with TU Berlin and its spin-off organization TissUse GmbH on the “NanoINHAL” project to investigate the impact of nanoparticles on the human body. The project is funded by the German Federal Ministry of Education and Research (BMBF). “We are able to analyze the biological impact of the aerosols directly and easily using in vitro methods – and without animal testing,” says Dr. Tanja Hansen, Group Manager at Fraunhofer ITEM.
Combining two existing technologies has made this possible: The multi-organ chip Humimic Chip3 from TU Berlin and its spin-off organization TissUse, and the P.R.I.T.® ExpoCube®, developed by Fraunhofer ITEM. The Humimic Chip3 is a chip the size of a standard laboratory slide measuring 76 x 26 mm. Tissue cultures miniaturized 100,000-fold can be placed on it, with nutrient solutions supplied to the tissue cultures by micropumps. In this way, for example, tissue samples of the lung and liver and their interaction with nanoparticles can be artificially recreated.
Four of these multi-organ chips fit into the P.R.I.T.® ExpoCube®. This is an exposure device used to study airborne substances such as aerosols in vitro. Using a sophisticated system of micropumps, heating electronics, aerosol lines and sensors, the ExpoCube® is able to expose the cell samples on the multi-organ chip to various aerosols or even nanoparticles at the air-liquid interface – as in the human lung – in a controllable and reproducible manner.
The nanoparticles flow through a microduct, from which several branches lead downward to conduct the air and nanoparticles to the four multi-organ chips. “If lung cells are to be exposed at the air-liquid interface, numerous parameters come into play, such as temperature, the flow of the culture medium in the chip, and the aerosol flow. This makes experiments of this kind very complicated,” Hansen explains.
The system is currently undergoing further optimization. At the end of the project, the combination of NanoCube and multi-organ chip will facilitate detailed studies of aerosols in vitro. Only then will it be possible to investigate the direct impact of the potentially harmful nanoparticles on the respiratory tract and, at the same time, possible effects on other organs, such as the liver.