The ability for controlled manipulation of cells and viruses is an essential prerequisite in the biotechnological industry. Many applications require either very pure samples or a sufficiently high concentration of biological micro-and nanoparticles. Appropriate and efficient separation methods for small amounts occurring in the lab-on-a-chip technology, are currently not yet present. The development is challenging due to complex non-linear superposition effects in electrorheological microchips causing various instabilities. A joint research project of Fraunhofer IBMT and Fraunhofer ITWM offers the possibility to virtually test certain parameter sets for a specific biochip design with respect to instabilities and other undesirable side effects. Based on these results improved designs will be developed.

Within the project, the development of a cell- and virus trap will prove that the additional use of computer simulation expands the possibilities of the lab-on-a-chip technology significantly. The traveling-wave technology which is promoted by Fraunhofer IBMT allows for the control of the dynamics of cells and viruses in micro-structured chips in an extremely precise way: High frequency fields induce fluid flow. Particles, cells or viruses in the liquid can be moved almost everywhere in a plane. For certain electrode configurations, however, complex three-dimensional vortex structures were observed which may be used for particle enrichment methods. Their cause wasn't understood yet, preventing their targeted use.

As basis for the simulations, a electro-hydrodynamic model was derived. This allowed for the determination of the physical mechanisms for the observed vortices. To use it in real geometries, the three-dimensional electro-hydrodynamic model was implemented numerically. The basis for the implementation and visualization of the occurring phenomena is the software platform CoRheoS. When using the Fraunhofer IBMT's electrode configuration in the CoRheoS simulation, the experimentally observed vortex structure on the computer is accurately reproduced. Thus, the decisive step has been taken to develop highly selective micro-traps for viruses and cells from the currently used lab-on-a-chip architectures.