Joachim Wiest1, Frank Schulze2
ALTEX Proceedings, 2021, 9, 1, 329
Corresponding author’s e-mail: firstname.lastname@example.org
1 cellasys GmbH
2 BfR – Centre for Documentation and Evaluation of Alternative Methods to Animal Experiments
Organ-on-chip (OoC) systems are a promising alternative to the still common animal experimentation. However, when compared to OoC systems found in literature such as lung, liver or kidney, bone is underrepresented as indicated by the rather low number of
proposed systems. One reason is that the development of bones in-vitro is a time-consuming process that can take up to several weeks. Currently, the process of matrix mineralization can only be investigated by end-point assays that require the destruction of the organoid. Therefore, a sensor-based, reliable and robust method for a non-invasive and continuous determination of in vitro matrix mineralization would be of great advantage, especially when 3D constructs are cultured in microphysiological bioreactors. In the presented work, we show data from impedance measurement on a collagen scaffold-dummy with osteogenic medium. Measurements were performed in a bioreactor (ID = 13 mm, height = 3mm) which was sandwiched by two impedance foils (Bio24, well B3 with passivated feed line). For impedance measurement a VersaSTAT 3 was used. Impedance spectroscopy from 1 Hz to 1MHz with an RMS of 30 mV was performed. The setup was mounted in a Faradic cage which was heated to 37°C. With the performed measurement we were able to distinguish pure osteogenic medium from a medium soaked collagen scaffold by approximately 60 Ω in the real part. During the performed proof-of-principle measurement no clear difference in the imaginary part of the impedance was visible. Further measurements with mineralized bone tissue are planned to further investigate the possibilities of the technology. The results indicate that the proposed geometry can be used to perform impedance measurement at bone scaffolds. Furthermore, a fixed frequency of 10kHz and 30mV seems to be suitable for the measurement.