Label-Free Impedance-Activated Acoustic Sorting of Cells From Structural to Molecular Scale in Microfluidics

Label-free, noninvasive, and high-throughput analysis and sorting of cells are essential capabilities in modern biomedicine, particularly for investigating cellular heterogeneity, functional phenotyping, and precision medicine. In this study, we present an integrated and broadly applicable microfluidic system capable of real-time electrical profiling and on-demand acoustic sorting across multiple physical and functional scales, from cell type, cellular biomechanics to molecularly regulated membrane-functional states. The system achieved up to 98% purity in size-based sorting, and accurately distinguished normal and perturbed erythrocytes exhibiting rigidity-associated impedance shifts induced by chemical crosslinking, oxidation, or ion-mediated regulation. At the level of molecularly regulated membrane function, we introduced an optogenetic model and achieved label-free sorting of optogenetically induced and pharmacologically modulated cell states based on protein-mediated membrane electrical responses. The system demonstrated its broad applicability for analyzing and sorting cell states across distinct biological contexts, providing a scalable and biocompatible solution for functional state identification and label-free sorting.