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BP: Fachverband Biologische Physik

BP 11: Franco-German Session: Bacterial Biophysics I

BP 11.1: Vortrag

Dienstag, 10. März 2026, 09:30–09:45, BAR/0106

Monitoring of biofilms formation using a QCM-D — •Philipp Sievers¹, Andreas Böttcher¹, Günther Räcker², Felix Bosch², and Diethelm Johannsmann¹ — ¹Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str. 4, 38678 Clausthal-Zellerfeld, Germany — ²Feindrahtwerk Adolf Edelhoff GmbH & Co. KG, Am großen Teich 33, 58640 Iserlohn, Germany

Biofilms formed by bacteria are a severe problem in many industries. Biofilm formation leads to biofouling, which limits the heat transfer (e.g. in heat exchangers) or contaminates process water. Regular biofilm removal often is necessary. In order to reduce cost, an online detection of biofilm formation is highly desirable.

An instrument is described, which monitors biofilm formation based on a quartz crystal microbalance with dissipation monitoring (QCM-D). In contrast to a conventional gravimetric QCM, which would rely on the shift in the resonance frequency, the most useful parameter to quantify biofouling was found to be the increase in the resonance bandwidth. This is due to the fact that biofilms consist of soft material loosely attached to the resonator, mostly leading to the dissipation of energy. This behavior is recognized based on a specific overtone dependence of the bandwidth, namely increased bandwidth (**) being the same on the different overtones. This feature is best explained with a mechanical equivalent circuit containing a single dashpot coupled to the resonator surface.

Keywords: Biofouling; Biofilm; QCM-D; Viscoelasticity; Biosensors