"Intelligent" plastic as a transformation artist

Cells: well-being and distance at the push of a button

At 37 ° C, biological cells adhere to the new plastic (above), cooled to room temperature, the cells avoid contact, contract into spheres, and are easily flushed down (bottom). © Fraunhofer IAP
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Fraunhofer researchers have developed a plastic that can change its properties at the touch of a button: at 37 ° C it is water-repellent and an ideal breeding ground for biological cells. At room temperature, however, it attracts water and the cells dissolve. The new plastic could play an important role in drug development in the future.

How do new drugs and drugs affect the body - especially the cells? Can the doctor use them safely or do they have a toxic effect? To answer such questions, drug companies with new drugs will have to perform a variety of specified toxicity tests. Cell cultures are based on these experiments: researchers place individual cells in a small plastic dish, add nutrient solution and place the dish in the incubator at 37 ° C.

Cells "stick" to the shell

To make the cells feel as comfortable and multiply as possible, researchers use polystyrene trays. When sufficient cells are grown, the drug is added. To investigate how the cells react to the drug, however, the scientists must remove the cultured cells from the shell. Not a simple matter: the cells stick to the shell so tightly that the researchers have to add an enzyme to detach it from the plastic.

"Especially the cell types that are used for toxicity tests are very sensitive and can be damaged by the added enzyme. The statements are then difficult to interpret: One can not say flawlessly, to what extent damage caused by the detachment of the cells their response to the drug, "says Claus Duschl from the Fraunhofer Institute for Biomedical Engineering IBMT in Potsdam-Golm.

Switchable plastic developed

The team led by Jean-François Lutz from the Fraunhofer Institute for Applied Polymer Research IAP, together with his colleagues from the IBMT and the Max Planck Institute for Colloids and Interfaces, has now developed a plastic that can change its properties. display

"At 37 ° C, the temperature at which the cells are grown, the plastic is water-repellent - the cells feel very comfortable and spread out. If the plastic is cooled to 25 C, ie to room temperature, the material absorbs water. The cells avoid contact, become almost spherical and can be easily washed down. The addition of an enzyme is thus superfluous, says Lutz.

Plastics for Petri dishes

Although there are already similar switchable plastics. The big difference with the new plastic: its basis is polyethylene glycol, PEG for short. In contrast to the other switchable plastics, this material is biocompatible - cells grow very well on it. Another advantage: The material is water-soluble and non-toxic. Lutz hopes that in about two to three years, Petri dishes could be coated as standard with the new switchable plastic.

(idw - Fraunhofer-Gesellschaft, 03.09.2008 - DLO)