Unraveling the dielectric heterogeneity response of cell lines under electroporation: a microfluidic single-cell on-chip system.

In the clinical application of irreversible electroporation for tumor therapy, individual differences in cellular electrical responses often lead to the reliance on empirically selected treatment parameters, which easily cause over/under-treatment in patients and hinder the development of precision tumor therapy. To clarify the response mechanism induced by single-cell individual differences, this study developed an experimental platform integrating microfluidic chip technology, dielectrophoresis (DEP), electrorotation (EROT), and electroporation (PEF) technologies, enabling the full process of single-cell "capture-rotation-electroporation-re-rotation" on one chip. By extracting four core dielectric parameters (conductivity and permittivity of membrane and cytoplasm) via rotation spectrum analysis and the size effect of cell, we proposed a semi-quantitative Electroporation Sensitivity Index (EPI). The EPI is grounded in the cumulative contribution of static intrinsic sensitivity and dynamic promotion to quantify cellular responses. This study used four cell lines (A549, HUH-7, U251, B16F10) for validation. The results showed that: the platform stably captured cells at the center of the electrodes and induced rotation, with the coefficient of determination (R²) of the rotation spectrum fitting curves all greater than 0.97, confirming the strong robustness of the method. The EPI ranking of the four cell lines (B16F10: 3.628 > A549: 2.678 > U251: 2.364 > HUH-7: 1.974) was completely consistent with the actual ranking of maximum instantaneous mortality (IR) (B16F10: 82.28% > A549: 81.87% > U251: 78.81% > HUH-7: 60.61%), verifying the effectiveness of EPI in analyzing cell electroporation responses. This study provides a quantitative framework for decoding tumor heterogeneity, laying a theoretical foundation for precision electroporation therapy.