Multielectrode biosensor chip for spatial resolution screening of 3D cell models based on microcavity arrays

Area of Science:

• Bioengineering
• Cell Biology
• Materials Science

Background:

• Three-dimensional (3D) cell models more accurately mimic in vivo conditions than 2D cultures, driving demand for advanced in vitro analysis tools.
• Existing methods for analyzing 3D cell cultures often lack the speed, non-invasiveness, real-time capability, and spatial resolution required for detailed studies.
• Microcavity arrays (MCAs) combined with impedance spectroscopy offer potential for spatial resolution but have been limited by opaque substrates and geometric constraints.

Purpose of the Study:

• To develop novel microcavity arrays (MCAs) fabricated from glass using selective laser etching (SLE) to overcome limitations of previous silicon-based designs.
• To enhance spatial resolution in bioelectronic analyses of 3D cell models by increasing electrode combinations and integrating a z-axis electrode.
• To demonstrate the capability of these new glass MCAs for analyzing heterogeneous cell models and localized drug effects.

Main Methods:

• Fabrication of microcavities in fused silica and borosilicate glass using selective laser etching (SLE) to remove geometric constraints.
• Development of MCAs with variable bases, incorporating up to eight measurement electrodes per cavity for increased electrode combinations.
• Integration of a central cone electrode at the cavity bottom to improve spatial resolution along the z-axis.
• Characterization of MDA-MB-231 spheroids and other cell spheroids using the developed glass MCAs and impedance spectroscopy.

Main Results:

• Successfully fabricated glass MCAs without geometric constraints, enabling flexible electrode configurations.
• Demonstrated enhanced spatial resolution through increased electrode combinations and the addition of a z-axis electrode.
• Showcased the ability of the MCAs to reveal heterogeneity in cell models, exemplified by impedance spectra of MDA-MB-231 spheroids.
• Confirmed the broad applicability of the glass MCAs across various cell spheroid analyses.

Conclusions:

• The SLE-fabricated MCAs significantly advance bioelectronic analyses of cellular changes in heterogeneous 3D models.
• These improved MCAs offer enhanced spatial resolution and flexibility compared to previous designs.
• The developed technology holds promise for benefiting the bioelectronic analysis of electrophysiologically active cells and tumor biopsy samples.