UC Santa Cruz

Living cells undergoing cellular differentiation, chronological aging, and malignant progression could exhibit dramatically different biophysical characteristics. Accurate quantification of the intrinsic mechanical properties of cells is of both practical and fundamental significance in biological research and clinical diagnostics. Here, we introduce Non-invaSIve acousTo-mechanophEnotyping (ON-SITE) for high-throughput (~ 5 × 104 cells/hr) on-the-fly quantification of single-cell mechanics in continuous flow without any physical contact and labeling. ON-SITE integrates two sequential modes of acousto-dynamic operation in a staged fashion, enabling three-dimensional focusing of cells into a tight line and subsequent touchless steering of them orthogonal to laminar flow, tracing out a parabola-like trajectory. This unique dual functionality offers real-time probing and evaluation of cell mechanical properties with excellent spatiotemporal resolution by tracking cell axial transit path lengths over its entire trajectory. We identified multiple critical biophysical factors (size, density, compressibility) that contribute to the dynamic motion of cells by analytical modeling and experimental approaches. We demonstrate highly efficient, reliable, and precise quantification of the cell elastic modulus of three distinct wild-type hematopoietic progenitors and their conditionally reprogrammed counterparts upon treatment with cytoskeleton-perturbing molecules. Remarkably, the subtle microscopic differences (~ 1 – 12 %) in cell elastic modulus are unraveled on an ultrafast timescale (~ 0.3 s) using acoustic waves that are generated at a clinically safe power (~ 2 W/cm2) and frequency (~ 13 MHz) level.