Quantifying mechanical opacity as a novel indicator for single-cell phenotyping via integrated dynamic mechanical compression and impedance flow cytometry

) to capture impedance changes during deformation and relaxation, offering a compact and interpretable mechanical signature. Using this system, we demonstrate distinct mechanical opacity profiles among three human cancer cell lines (HeLa, SW1990, BxPC-3), reflecting their inherent biomechanical differences. Fluorescence assays confirm that lower mechanical opacity corresponds to increased membrane permeability, linking electrical measurements to underlying structural changes. Our work establishes mechanical opacity as a dynamic, label-free marker for single-cell mechanics, bridging mechanical stimulation and electrical detection. This approach expands the capability of impedance flow cytometry for applications in cell classification, drug screening, and disease diagnostics.