Simulation-Based Microfluidic Deformation Mapping for Region-Dependent Apparent Young's Modulus Estimation of Single Cells.

High-throughput microfluidic deformation assays enable label-free single-cell mechanophenotyping by quantifying how cells deform under controlled hydrodynamic loading. These approaches commonly extract deformation-related observables, such as projected area, axis ratio, and deformation index, and use them as indicators for cellular mechanical properties. However, deformation is not solely determined by stiffness; it is a coupled outcome of cell size, local hydrodynamic stress, and intrinsic mechanical response. Therefore, we present a simulation-based microfluidic framework for estimating region-dependent apparent Young's modulus (E, a quantitative indicator characterizing cellular mechanical stiffness) from diameter-deformation measurements at the single-cell level. A three-region microfluidic channel is designed to impose distinct hydrodynamic loading conditions, while numerical simulations establish quantitative maps linking cell diameter, deformation, and E. Based on these results, region-specific nonlinear surface models are constructed to invert experimental diameter-deformation measurements into E values. Finally, application to primary T cells and K562 cells demonstrates clear region-dependent differences in E, highlighting the influence of local loading conditions on inferred mechanical properties. Overall, this work provides a simplified but practical route for transforming deformation-based phenotypes into quantitative, loading-aware mechanical parameters for single-cell analysis.