Impedance Spectroscopy for Toxicity Testing
Martin Dominguez
Cronus Technologies Ltd.
Barrier Forming Tissue
Epithelial and endothelial cell layers form selectively permeable barriers
The Concept
Growing cell layers on permeable membranes
The Concept
Measuring the electrical impedance of epithelial and endothelial cell layers under
physiological conditions
Understanding Impedance Spectra
Contributions stemming from CPE and RMED
Understanding Impedance Spectra
The formation of a plateau at mid-range frequencies is attributable to the cell layer’s
resistance TER and capacitance CCL
Understanding Impedance Spectra
An increase in the resistance TER shifts the plateau upwards
Understanding Impedance Spectra
An increase in the capacitance CCL narrows the plateau
Time-Lapse Impedance Spectroscopy
The Setup
The Setup
cellZscope
Automated cell monitoring device
Monitoring of MDCK-II Cells
Formation of a differentiated cell monolayer with established cell-cell junctions
cellZscope vs. „Chopstick“ Electrodes
Comparing TER values measured on MDCK-II cell layers
Long Term Monitoring of Caco-2 Cells
Comparing growth dynamics of different cell lines
EDTA Treatment of MDCK-II Cells
Effects on the tight junction network
140
120
80
60
40
Cont r ol
2mM EGTA
4mM EGTA
EGTA
r emoved
1mM EGTA
20
EGTA
added
TER ( %)
100
0
0. 0
0. 5
1. 0
1. 5
Ti me ( h)
2. 0
2. 5
MBCD Treatment of MDCK-II Cells
Dose dependent response in TER and Ccl to cholesterol depletion
Testing the Toxicity of Nanoparticles
Exposure of MDCK cells to different types of particles
+ Particles
+ Triton X100
180
160
Control
Control
140
TER (%)
120
Carbon Black*
Carbon Black*
100
ZrO2*
ZrO2*
80
60
ZnO - NP*
ZnO - NP*
40
*
20
10 µg/cm²
0
0
5
10
15
20
25
Time (h)
Data courtesy of A. Kroll, J. Schnekenburger, University of Münster, Germany
Testing the Toxicity of Nanoparticles
Exposure of NRK52E cells to ZnO
+ ZnO
+ Triton X100
120
100
Control
Control
TER (%)
80
ZnO*
ZnO*
ZnO*
60
ZnO NP*
ZnO NP*
ZnO NP*
40
*
10 µg/cm²
20
0
0
5
10
15
20
25
Time (h)
Data courtesy of A. Kroll, J. Schnekenburger, University of Münster, Germany
cellZscope
Automated cell monitoring device