Real-time deformability cytometry: on-the-fly cell mechanical phenotyping

Abstract

We introduce real-time deformability cytometry (RT-DC) for continuous cell mechanical characterization of large populations (>100,000 cells) with analysis rates greater than 100 cells/s. RT-DC is sensitive to cytoskeletal alterations and can distinguish cell-cycle phases, track stem cell differentiation into distinct lineages and identify cell populations in whole blood by their mechanical fingerprints. This technique adds a new marker-free dimension to flow cytometry with diverse applications in biology, biotechnology and medicine.

High-throughput physical phenotyping of cell differentiation

“…However, both methods are time and labor intensive (tens of cells per hour), posing challenges for examining large populations of cells to either obtain statistically valid conclusions or identify rare sub-populations. Recent advances in micro-/nano-fabrication technologies have opened up a range of new mechanophenotyping technologies that can measure deformations of tens to hundreds of cells per second [11][12][13][14][15][16][17][18][19] . We recently reported a technology, called deformability cytometry, in which a cross-slot microfluidic channel is employed to generate a hydrodynamic extension zone where individual cells are exposed to uniform hydrodynamic stress and deformed 20 .…”

Measuring Cell Viscoelastic Properties Using a Microfluidic Extensional Flow Device

“…To address these issues, microfluidic tools have recently been explored as a strategy to measure cellular structural and mechanical properties with a rapidity that may be better suited to drug discovery and clinical application (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Although these approaches have indeed massively improved measurement throughput and reduced operator skill/bias issues relative to traditional measurements, the extraction of cell mechanical properties (e.g., elastic modulus) remains challenging, primarily due to complex viscous forces that severely complicate analysis of deformations.…”

“…Recently, Guck and colleagues performed rapid cell deformability measurements with a device that squeezed cells into a bullet shape as the cells passed through square constriction channels (18,19). By using a viscous medium (viscosity of m~15 mPa$s vs. 1 mPa$s for water at room temperature), the device could be operated at low Reynolds number (Re~0.1), thereby enabling the development of an analytical model from which elastic moduli of cells could be determined from the resulting deformations (19).…”

High‐throughput linear optical stretcher for mechanical characterization of blood cells

“…This approach is capable of distinguishing differences in cell populations, either by chemical treatments that affect the mechanical properties of the plasma membrane or cytoskeleton or in mixtures of RBC and neutrophils. The ability to apply optical forces decoupled from cell size is unique, as size is directly coupled to applied force via flow rate in other high-throughput methods (28,29). By separating deforming force from flow rate, one can fix hydrodynamic conditions while varying the applied force, allowing direct comparison between cell types of different stiffness and size at the same velocity.…”

“…One approach is the microfluidic cell deformability cytometer which are inexpensive to prototype, use small sample volumes (nanoliters), and employ laminar flow characteristics (24) allowing for predictable and controllable flow. For example, physical constrictions (25)(26)(27)(28) or inertial focusing flow (29)(30)(31) have been used to create contact or shear forces (> 1 nN (30)) capable of significantly deforming flowing cells. Large strains (>10% deformation) however, can damage cells and should be avoided when cell isolation and viability post-analysis are of interest.…”