Differential Inductive Sensor for Continuous Non-Invasive Cell Growth Monitoring in Disposable Bioreactors

Abstract

In this work, we present a low-cost sensor system for continuous non-invasive cell growth monitoring, especially for single use bioreactor (SUB) applications. The sensor system is based on a differential transformer. Using this differential setup, the influence of the primary magnetic flux is eliminated from the measuring signal, enabling highly sensitive non-invasive detection of permittivity changes in the culture medium. To evaluate the sensor, E. coli cultivations are performed and the cell density is measured through the polymer foil of a SUB. We found a linear dependency with low data scattering between measuring signal and cell density.

Keywords

• cell growth monitoring
• single use bioreactor
• inductive permittivity measurements
• dielectric spectroscopy
• differential transformer