Automated Electrorotation System for High-Throughput Dielectric Cell Characterization

Objective: This work presents ROT-QSG, a compact, automated, and user-friendly electrorotation system for label-free dielectric characterization of biological cells, enabling applications in disease diagnosis, drug discovery, and personalized medicine. Methods: The ROT-QSG system consists of three main components: (1) a custom electronic device—Quadrature Signal Generator (QSG); (2) a specifically designed electrorotation chip—ROT-chip; and (3) a dedicated image processing algorithm—Pixel Intensity (PxI)—which enables automatic, operator-independent extraction of cell rotation data. Electrorotation allows the dielectric characterization of cells by analyzing their rotational response to varying electric field frequencies, generating the rotation–frequency spectrum (ROT-spectrum). To ensure high consistency and repeatability, the entire experimental workflow—from signal generation to spectrum extraction—has been fully automated through a dedicated experimental control algorithm. Results: The system was validated by analyzing three immortalized cell lines (CaCo-2, CCD-841, and OPM2), from which ROT spectra and corresponding cell membrane capacitance values were successfully extracted. Conclusion: The comparative study revealed clear differences in membrane capacitance among the three cell types, confirming the system's capability to detect meaningful dielectric variations. The repeatability of measurements within each cell line and the observed distinct spectral differences between the cell lines demonstrate its sensitivity to variations in membrane morphology and structural organization. Significance: The system, designed with a strong focus on integration, automation, and ease of use in biological settings, has the potential to enhance dielectric characterization across a wide range of cell types, contributing to a deeper understanding of cellular functions and disease mechanisms.