![](bg4.png)
observed at the end of the differentiation process, as
shown in Fig. 3.
These results suggest the differentiation in cell
lines correspond to differences in bioimpedance
measured, although the work should be completed in
the future with more quantitative analysis.
4 CONCLUSIONS
A new oscillating circuit based on Impedance
Spectroscopy has been presented for the real-time
monitoring of the cellular growth and differentiation
processes of stem cells. The technique has been first
applied to muscle stem cells.
The circuit proved to be useful for monitoring
the processes of cell growth and estimating the fill
factor of muscular stem cell cultures. The
oscillation-based circuit proposed successfully
detected this cell growth, in a similar way as in other
cell types. A useful threshold for the fill factor of
70% has been positively tested on stem cell-cultures,
to activate them towards differentiation by changing
the medium.
Real-time monitoring of cell differentiation can
be also enabled with the proposed impedance
spectroscopy method. An initial decrease in cell
proliferation was detected at the change of medium
to differentiation medium. However, after a few
hours, a linear increase in the monitored amplitude
was recorded, corresponding to the differentiation
process, which was contrasted with microscope
images. A final higher amplitude levels in
differentiated cell cultures were detected. The
technique could be useful for determining the degree
of differentiation achieved, although more detailed
tests would be needed.
No significant differences between cell cultures
where electrical impedance was used and the control
ones. However, higher levels of intensity could be
used, which could influence the process of cellular
differentiation and facilitate the development of
cells, or even facilitate the contraction of muscular
structures, what could be of importance in the design
of new bioreactors for tissue engineering.
ACKNOWLEDGMENT
This work was supported in part by the Spanish
founded Project: Integrated Microsystems for cell
culture test (TEC2013-46242-C3-1-P): Spanish, co-
financed with FEDER program.
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