[Zurück]

C. Koch, P. Palmesi, M. Brandstetter, S. Radel, M. Gröschl, B. Lendl:
"Towards ultrasonic enhanced mid-IR fiber optic probes for in-line bioprocess monitoring";
Vortrag: 1st EAA - EuroRegio 2010, Ljubljana, Slovenia; 15.09.2010 - 18.09.2010; in: "1st EAA - EuroRegio 2010 Congress on Sound and Vibration", (2010), ISBN: 978-961-269-283-4; Paper-Nr. 220, 1 S.

In bioprocess technology there is a need to monitor the concentration of molecules present in the fermentation broth for bioprocess monitoring and for efficient bioprocess control. The target analytes are either dissolved in the fermentation broth or contained in the cells.
Recently, fibre optic mid-IR probes have been developed for in-line bioprocess monitoring using attenuated total reflection (ATR) to assess the spectra and thus retrieve the highly molecular specific information. The interaction volume of the mid-IR beam and the sample
solution is determined by the penetration depth of the evanescent field (a few micrometers). This leads to difficulties in concentrating and removing cells in and from this area, respectively. When an acoustic standing wave field acts on a suspension, acoustic radiation forces are exerted on the suspended particles, leading to a separation of the particles from the host fluid. This so-called Ultrasonic Particle Manipulation is exploited in biological
applications, e.g. filtering and sorting of cells, when gentle handling is important. We have successfully combined the two techniques by placing an ultrasonic transducer opposite the
ATR element of the mid-IR fibre optic probe. By tuning the ultrasound frequency we were able to actively move the cells into and out of the evanescent field thus acquiring spectra of the cells only and the medium only, respectively. Initial results on measurement of yeast suspensions using the Ultrasonic enhanced mid-IR fibre optic probe in an experimental bioreactor will be presented.