Equivalent Circuit Modeling and Analysis for Microfluidic Electrical Impedance Monitoring of Single-Cell Growth.

Area of Science:

• Biophysics
• Microfluidics
• Biosensing

Background:

• Microfluidics enhances single-cell analysis for cell growth and heterogeneity studies.
• Electrical impedance spectroscopy (EIS) is a label-free technique for monitoring cells in microfluidic devices.

Purpose of the Study:

• Develop theoretical equivalent circuit models for in situ EIS sensing systems to interpret single-cell growth dynamics.
• Establish a link between EIS measurements and the biophysical properties of single cells.

Main Methods:

• Utilized finite element modeling and simulation to guide the development of equivalent circuit models (ECMs).
• Performed in situ EIS measurements of immobilized yeast cells in microfluidic devices.
• Developed a lumped parameter model fitted to experimental data.

Main Results:

• Extracted an equivalent volume fraction from ECMs to describe geometry-dependent sensing characteristics.
• Validated the theoretical model by correlating long-term impedance variations with cell growth.
• Demonstrated the feasibility of linking EIS data to cell biophysics.

Conclusions:

• The developed equivalent circuit models provide a robust framework for interpreting EIS data in microfluidic single-cell analysis.
• This approach enables accurate, label-free, and non-invasive monitoring of cell growth dynamics.
• The study validates the use of EIS for understanding the biophysics of single cells over time.