Impedance mapping with high-density microelectrode array chips reveals dynamic heterogeneity of in vitro epithelial...

Area of Science:

• Biomedical Engineering
• Cell Biology
• Materials Science

Background:

• Epithelial tissues in vitro exhibit complex, heterogeneous differentiation difficult to analyze with conventional methods.
• Traditional assays lack the spatiotemporal resolution needed for dynamic tissue monitoring.
• Solid substrate systems with integrated electrodes offer improved analysis for organ-on-chip applications.

Purpose of the Study:

• To evaluate the capability of CMOS-integrated high-density microelectrode arrays (HD-MEAs) for real-time, label-free monitoring of epithelial tissue dynamics.
• To assess the spatiotemporal resolution of impedance sensing for analyzing cellular proliferation, barrier formation, and 3D structure development.
• To demonstrate the utility of HD-MEAs in detecting chemically induced epithelial barrier disruption.

Main Methods:

• Utilized a 16,384-electrode CMOS-integrated HD-MEA chip with subcellular-sized electrodes (8 μm diameter).
• Employed electrochemical impedance monitoring at 1 kHz (|Z|_1kHz) to track Caco-2 cell lifecycle.
• Correlated impedance map data with optical imaging for cellular-level analysis.

Main Results:

• Observed significant changes in |Z|_1kHz (up to +453%) during Caco-2 cell culture over 7 days.
• |Z|_1kHz maps accurately reflected Caco-2 cell proliferation and 3D dome formation, aligning with optical images.
• Demonstrated higher impedance decrease (-41%) in 3D cell domes versus adherent cells (-16%) during barrier disruption, indicating enhanced sensitivity.

Conclusions:

• CMOS-integrated HD-MEAs provide high spatiotemporal resolution for label-free, real-time monitoring of epithelial tissue dynamics.
• This technology enables detailed analysis of cellular heterogeneity and barrier function in organ-on-chip models.
• HD-MEA impedance sensing offers a sensitive and informative approach for evaluating tissue barrier integrity and detecting disruptive agents.