In life sciences, the mechanical properties of suspended cells have long been established as a label-free biomarker of biological function and disease and are of high importance when traditional molecular markers are either not available or not wanted, e.g. in regenerative medicine. Concerted utilization of cell mechanical phenotyping in translational medicine has so far been hampered by acquisition throughput, excessive post processing, or low-throughput real-time analysis.
Real-time deformability cytometry (RT-DC) expanded mechanical cell assays to fast on-the-fly phenotyping of large sample sizes and is a microfluidic technology, which is based on the shear-induced deformation of cells in a narrow channel. Translocating cells are being imaged using a high-speed CMOS camera and analysed on-the-fly. RT-DC demonstrated its relevance in life science research, e.g. by observing the activation of immune cells in whole blood and by describing the membrane dynamics of Malaria pathogenesis. In contrast to fluorescence-based techniques like flow cytometry with a parameter space that can be expanded by additional molecular probes and laser lines, RT-DC has been restricted to a single material parameter, e.g. the elastic modulus.
In our recent publication we introduce dynamic real-time deformability cytometry (dRT-DC) for simultaneous cell mechanical measurements of elastic and viscous properties at a throughput of up to 100 cells per second. Utilizing Fourier decomposition, our microfluidic method is able to disentangle cell response to complex hydrodynamic stress distributions and to determine viscoelastic parameters independent of cell shape. We demonstrate the application of our technology for peripheral blood cells in whole blood samples including the discrimination of B- and CD4+ T-lymphocytes by cell rheological properties. This technology might be highly relevant in cardiovascular research where the response of the immune system during inflammatory cardiac diseases might be monitored by a simple blood test based on cell mechanical properties.
March 2019