Browsing by Author "Rauer, Sebastian Bernhard"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Item3D‐Printed Bioreactor with Integrated Impedance Spectroscopy for Cell Barrier Monitoring(Weinheim : Wiley, 2021) Linz, Georg; Rauer, Sebastian Bernhard; Kuhn, Yasmin; Wennemaring, Simon; Siedler, Laura; Singh, Smriti; Wessling, MatthiasCell 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.
- ItemPorous PEDOT:PSS Particles and their Application as Tunable Cell Culture Substrate(Weinheim : Wiley, 2021) Rauer, Sebastian Bernhard; Bell, Daniel Josef; Jain, Puja; Rahimi, Khosrow; Felder, Daniel; Linkhorst, John; Wessling, MatthiasDue to its biocompatibility, electrical conductivity, and tissue-like elasticity, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) constitutes a highly promising material regarding the fabrication of smart cell culture substrates. However, until now, high-throughput synthesis of pure PEDOT:PSS geometries was restricted to flat sheets and fibers. In this publication, the first microfluidic process for the synthesis of spherical, highly porous, pure PEDOT:PSS particles of adjustable material properties is presented. The particles are synthesized by the generation of PEDOT:PSS emulsion droplets within a 1-octanol continuous phase and their subsequent coagulation and partial crystallization in an isopropanol (IPA)/sulfuric acid (SA) bath. The process allows to tailor central particle characteristics such as crystallinity, particle diameter, pore size as well as electrochemical and mechanical properties by simply adjusting the IPA:SA ratio during droplet coagulation. To demonstrate the applicability of PEDOT:PSS particles as potential cell culture substrate, cultivations of L929 mouse fibroblast cells and MRC-5 human fibroblast cells are conducted. Both cell lines present exponential growth on PEDOT:PSS particles and reach confluency with cell viabilities above 95 vol.% on culture day 9. Single cell analysis could moreover reveal that mechanotransduction and cell infiltration can be controlled by the adjustment of particle crystallinity.
- ItemWet-Spinning of Biocompatible Core–Shell Polyelectrolyte Complex Fibers for Tissue Engineering(Weinheim : Wiley-VCH, 2020) Cui, Qing; Bell, Daniel Josef; Rauer, Sebastian Bernhard; Wessling, MatthiasPolyelectrolyte complex fibers (PEC fibers) have great potential with regard to biomedical applications as they can be fabricated from biocompatible and water-soluble polyelectrolytes under mild process conditions. The present publication describes a novel method for the continuous fabrication of PEC fibers in a water-based wet-spinning process by interfacial complexation within a core–shell spinneret. This process combines the robustness and flexibility of nonsolvent-induced phase separation (NIPS) spinning processes conventionally used in the membrane industry with the complexation between oppositely charged polyelectrolytes. The produced fibers demonstrate a core–shell structure with a low-density core and a highly porous polyelectrolyte complex shell of ≈800 μm diameter. In the case of chitosan and polystyrene sulfonate (PSS), mechanical fiber properties could be enhanced by doping the PSS with poly(ethylene oxide) (PEO). The resulting CHI/PSS-PEO fibers present a Young modulus of 3.78 GPa and a tensile strength of 165 MPa, which is an excellent combination of elongation at break and break stress compared to literature. The suitability of the CHI/PSS-PEO fibers as a scaffold for cell culture applications is verified by a four-day cultivation of human HeLa cells on PEO-reinforced fibers with a subsequent analysis of cell viability by fluorescence-based live/dead assay. © 2020 The Authors. Published by Wiley-VCH GmbH