Institute of Physical Chemistry > Research > Biofilm-Monitoring

Biofilm-Monitoring

NTH-Research Group: ElektroBak - Innovative Materials and Concepts for Microbial Electrochemical Systems (Sub-Project B3 - Biofilm-Monitoring)

The thickness of an electrochemically active biofilm, its cell density, stability and transport properties, the kinetics of its formation and its robustness against variable environmental conditions are of central importance for the efficiency and the practical benefits of bioelectrochemical cells.  The aim of this project is to develop a method for the in situ determination of the thickness and the shear stiffness of electrically active biofilms using acoustic torsional resonators.i  The acoustic and the electrochemical properties shall be correlated to develop a physical-electrochemical biofilm model.

Key issues are:

  • Does the current efficiency correlate with the film thickness? Is there an optimal film thickness?
  • Can the acoustic data be used in a control loop, that optimizes the environmental conditions to increase the current efficiency and the durability of the cell?
  • Is there a connection between the transport properties (protons, nutrients) and the viscoelastic properties of the biofilm?

A torsional resonator consists of a cylindrically shaped piezoelectric crystal, which is excited to a torsional vibration by electrodes on the side of the resonator. The resonant frequency is in the range of 50 kHz. The resonance frequency and bandwidth change when the resonator comes into contact with a sample. Using a viscoelastic model, these changes can be converted into a film thickness and an apparent stiffness of the film. The dotted line sketches the amplitude distribution of the shear wave.


Persons:
Philipp Sievers
,
Dr. Arne Langhoff
,
Prof. Diethelm Johannsmann

Link to the ElektroBak projects website.               
Link to subproject B3 on the ElektroBak projects website.

  • Bücking, W.; Du, B.; Turshatov, A.; Konig, A. M.; Reviakine, I.; Bode, B.; Johannsmann, D., Quartz crystal microbalance based on torsional piezoelectric resonators. Review of Scientific Instruments 2007, 78, (7), 074903.
 

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