C. Canali, K. Aristovich, L. Ceccarelli, L.B Larsen, Ø. G. Martinsen, A. Wolff, M. Dufva, J. Emnéus and A. Heiskanen
migration of cells during epithelial stratification. The cultured cells are adherent on the electrodes, modulating the interface impedance. Rahman et al. [ 31 ] used impedance spectroscopy to map in vitro cellular morphology using a circular 2D microelectrode array with 8 peripheral electrodes and a central counter electrode. Sun et al. [ 32 ] imaged a multi-nuclear single cell mould Physarum polycephalum grown on a 2D chip consisting of 16 equally spaced electrodes at the periphery of a circular cell culture chamber (Ø 6 mm). Meir and Rubinsky [ 33 ] presented a
In order to examine the cellular viability post encapsulation, sections of 1 mm thickness were taken from the centre of alginate discs containing 3T3 cells using a sterilized blade. The sections were immersed in 0.2 μL calceinacetoxymethylester (calcein-AM) for 15 min and 2.5 μL propidiumiodide (PI) for 5 min in S-DMEM at 37 o C. The calcein-AM was cleaved to form calcein in the presence of esterases in live cells resulting in photon emission at a wavelength around 515 nm. In the case of dead-cells, the PI penetrated the cell and nuclear membrane
Uwe Pliquett, Dieter Frense, Markus Schönfeldt, Christian Frätzer, Yong Zhang, Brian Cahill, Michael Metzen, Andreas Barthel, Thomas Nacke and Dieter Beckmann
plasma) surrounded by an insulating membrane (plasma membrane). The extracellular space is filled with electrolyte as well, but may have a very distinct conductivity with respect to the conductivity of the cytoplasm. Although the cytoplasm contains membrane systems (e.g. endoplasmatic reticulum, Golgi apparatus, nuclear membrane or other membrane enclosed organelles) a pure resistive model for this part is often sufficient for a practical approach [ 29 ; 30 ].
Since intact cell membranes show a low conductance, the low frequency current (f < 10 kHz) will