Application of impedance spectroscopy for analysis of BeWo clone b30 human choriocarcinoma cell line
Objectives: BeWo cells are used for the construction of in vitro models of placental barrier. Only the early placenta possesses multiple trophoblast layers whereas third-trimester placenta consists of a single trophoblast layer. BeWo cells do not undergo contact growth inhibition and form multilayer structures. It is important to control the cell state for transport experiments. Impedance spectroscopy was applied for electrical characteristic studying during BeWo cell growth and in response to HIF-1 activator.
Methods: 30,000 cells per insert were seeded into a 96-well Transwell plate (1 μm pore size). After 48 h a potent HIF-1 activator D014-0021 was added at 10 μM concentration. Impedance spectra were acquired with impedance spectroscopy system (Bioclinicum, Russia). For the extraction of electrical parameters, the equivalent electrical circuits were used. Student's t-test was used to calculate the statistical significance.
Results: It was predicted from the mathematical model that medium resistance (Rmed) and the radius of the impedance hodograph (and hence TEER) will rise linearly with the number of layers. In the case of one layer, the radius can rise due to the formation of tight junctions but the Rmed should remain stable, but the data shows increasing TEER and Rmed. There is a statistically significant difference in Rmed between 48 and 96 h. It can be concluded that after 48 h the BeWo cells form multilayer structures. The addition of D014-0021 leads to a slight increase in TEER after 6 h and a significant decrease in TEER and capacitance after 27 h.
Conclusion: It was shown that formation of multilayer structures can be readily detected with impedance spectroscopy and hence it can be used for quality control of the in vitro placental models. It is possible to use impedance spectroscopy for detection of additional parameter changes such as electrical capacitance.
This work is supported by the Russian Science Foundation (project No. 16-19-10597).