Christian Klenk1,2 and Joachim Wiest1,2*
ALTEX Proceedings, 2021, 9, 1, 207
1 cellasys GmbH, Kronburg / Germany
2 Technical University of Munich, Heinz-Nixdorf-Chair of Biomedical Electronics, Department of Electrical and Computer Engineering, TranslaTUM, Munich / Germany
Corresponding author: firstname.lastname@example.org
A new protocol based on a microphyiometric system (McConnell et al., 1992, Hartung et al., 2010, Wiest et al., 2016, Alexander et al., 2018, Brischwein and Wiest, 2019) to analyze cell culture medium (CCM) is described. With the presented cellasys #8 protocol, significant data can be gained in 24 h compared to conventional weaning experiments which need several weeks to perform. First, L929 cells are supplied for 6 hours with DMEM + FBS reference medium to gain initial data. In a second step, 6 hours of the investigated test medium is supplied to see if there are any changes in cellular vitality or morphology. Then again 4 hours DMEM + FBS and 4 hours of test medium to monitor if the effect of the CCM to the cells is reversible. The experiment ends with 4 hours of test medium + 0.2% SDS to induce cell death. In the presented work, two chemically defined CCM and a common serum-containing medium DMEM + FBS were tested on the L929 cell line. Compared to the reference medium, cells in the DMEM/Ham’s F12 + ITS medium pursue a loss in adherence, but no decrease in extracellular acidification rate. This was substantiated by the observation that the acidification rate remained constant and the impedance recovered after changing back to the reference medium. Cells in NCTC 135 retained their impedance values but lost vitality. It seems reasonable to suppose that cells in NCTC 135 medium are slowly suffering as indicated by a slow decrease in impedance and highly fluctuating acidification rates. Further experiments for the presented method could be the improvement of the DMEM/Ham’s F12 + ITS medium. With the new method electrical cell-substrate impedance and extracellular acidification responds of the cells can be measured immediately and consequently the quality of new CCM can be quantified.
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