ROSTOCK, Germany - A cellular sensor made from cells grown on chips will be tested soon in a large clinical trial initiated by a Rostock University research team. The Cell Monitoring System (CMS) monitors biopsied cancer cells to establish both clinical prognosis and optimal treatment.

Ten years ago, the project started as a large research program funded by the German federal research ministry to develop an "intelligent slide," Bernhard Wolf, head of the biophysics chair at Rostock University, of Rostock, told BioWorld International. In addition to the microscopic picture, the intelligent slide should provide additional information about the status of cells.

"After examining thousands of tumors we realized that diagnostic methods based on classical immunochemical or molecular genetic techniques were not suited well enough to get insights into the complex cellular system," Wolf said. "Such invasive methods influence or even damage the cells, and they cannot analyze more than two or three parameters. Finally, we developed silicon-based chips equipped with various microsensors."

The central component of the system is a miniaturized chamber for cell and tissue culturing with a chip at the bottom. The chip is produced by semiconductor fabrication techniques and can be equipped with sensor arrays in the dimension of cell size as well as several thousand square micrometers.

The microsensors measure pH, oxygen, temperature, various inorganic ions and electrical signals originating from the cells. As the cells are accessible to light microscopy, various imaging and image analysis techniques can be applied. "There is no need of any invasive or toxic manipulation, so we can record dynamic processes over extended time periods," Wolf said. The data provide insights in the status of the cells, their behavior and metabolic activity, and reaction to added drugs.

"It took us almost five years to develop sensors that for several days withstand the solutions and liquid handling necessary to grow the cells," Wolf added. "To my knowledge we are the only ones to have such robust sensors." Wolf has filed for more than 40 patents since 1981.

The chips are produced as cheap disposables, but a more expensive and durable device for longer experiments is available as well. It can be connected to a camera to monitor changes in form, density, growth rate, etc., of the cells in an automated fashion. Eight-chip versions and microplates with planar microsensor arrays are under development, too.

"The system has already been tested clinically in small studies," Wolf said. "Now we are starting a statistically validated, broad study. In the end we will be able to correlate the parameters we measure with the clinical course of cancer diseases and drug recommendations."

However, the CMS is not limited to cancer studies, but can be used for target-validation and drug-response studies, a market at least as big as cancer diagnostics. In addition, it can be applied to food, water and environmental analysis.

Wolf said he was co-founding a company to bring the system to the market and to develop it for further applications.