3D‐Printed Bioreactor with Integrated Impedance Spectroscopy for Cell Barrier Monitoring

• Published in: Advanced materials technologies 2021-06, Vol.6 (6), p.n/a
• Main Authors: Linz, Georg, Rauer, Sebastian Bernhard, Kuhn, Yasmin, Wennemaring, Simon, Siedler, Laura, Singh, Smriti, Wessling, Matthias
• Format: Article
• Language: English
• Subjects: 3D‐printing; Caco‐2; electrical impedance spectroscopy; organ‐on‐a chip; transepithelial electrical resistance
• ISSN: 2365-709X; 2365-709X
• DOI: 10.1002/admt.202100009

Cell culture experiments often suffer from limited commercial availability of laboratory‐scale bioreactors, which allow experiments to be conducted under flow conditions and additional online monitoring techniques. A novel 3D‐printed bioreactor with a homogeneously distributed flow field enabling epithelial cell culture experiments and online barrier monitoring by integrated electrodes through electrical impedance spectroscopy (EIS) is presented. Transparent and conductive indium tin oxide glass as current‐injecting electrodes allows direct visualization of the cells, while measuring EIS simultaneously. The bioreactor's design considers the importance of a homogeneous electric field by placing the voltage pick‐up electrodes in the electrical field. The device's functionality is demonstrated by the cultivation of the epithelial cell line Caco‐2 under continuous flow and monitoring of the cell layer by online EIS. The collected EIS data were fitted by an equivalent electric circuit, resulting in the cell layer's resistance and capacitance. This data is used to monitor the cell layer's reaction to ethylene glycol‐bis‐(2‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid and forskolin. These two model substances show the power of impedance spectroscopy as a non‐invasive way to characterize cell barriers. In addition, the bioreactor design is available as a print‐ready file in the Appendix, enabling its use for other scientific institutions. A fluid flow and the electrical field optimized 3D‐printed cell culture bioreactor reaching similar dimensions used in microfluidic cell culture systems known as organ‐on‐a‐chip is presented. The device's versatility is shown by cultivating the barrier‐forming cell line Caco‐2 and monitoring the cell layer's response toward barrier‐altering chemicals with electrical impedance spectroscopy.