Bioprocess Engineering

On line viability and vitality measurements

The viability and polarizability of cells are closely linked to each other. The polarizability of cells depends on dielectric properties of the cell. In bacterial cultivations cell polarizability can be linked to different growth stages in batch cultivations and production of acids or solvents, respectively.
The cell polarizability is electrooptically measured based on the change in orientation of an organism, when an electrical field is applied.
Orthogonal located light beams enable the measurement of optical density at random and alignment allocation. The timespan cells re-arrange in the electrical field is proportional to their polarizability (Maxwell-Wagner polarizability). Furthermore the viability and vitality of cells can be determined using special dyes and the flow cytometer. The principle is the determination of membrane integrity, cellular respiration and other functions of the cell.

Running Projects

Project supervisor

Prof. Dr.-Ing. Stefan Junne

Contact person:

Simon Täuber (


Former Projects