Electrical impedance tomography (EIT)-based intracellular conductivity imaging for non-invasive cell detection

Area of Science:

• Biophysics
• Cell Biology
• Electrical Engineering

Background:

• Non-invasive techniques for mapping intracellular electrical properties are limited.
• Understanding subcellular electrical variations is crucial for cell function studies.

Purpose of the Study:

• To develop and demonstrate a micro-Electrical Impedance Tomography (micro-EIT) system for non-invasive intracellular conductivity imaging at the single-cell scale.
• To reconstruct and differentiate conductivity distributions of cytoplasm and nucleoplasm based on electrical properties.

Main Methods:

• Development of a custom micro-EIT sensor using electron beam lithography for high spatial resolution.
• Application of frequency-differential EIT coupled with a single-cell equivalent circuit model for conductivity reconstruction.
• Validation using impedance spectra measurements on MRC-5 human lung fibroblast cell lines with varying protein expressions.

Main Results:

• Successful reconstruction of cytoplasm (σ_cyt) and nucleoplasm (σ_nuc) conductivity images.
• Demonstrated clear conductivity differences corresponding to variations in cellular protein expression.
• Verified EIT results with brightfield and fluorescence microscopy, confirming spatial accuracy.

Conclusions:

• This work presents the first non-invasive method for intracellular conductivity mapping using EIT.
• The micro-EIT system effectively distinguishes subcellular structures based on their electrical properties.
• The technique shows potential for analyzing cellular heterogeneity and function non-invasively.