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Single-Cell Biophysics: Measurement, Modulation, and Modeling
Poster Abstracts
135
74-POS
Board 37
Deformability Cytometry and 1D Fluorescence Imaging in Real-Time
Philipp Rosendahl
1
, Katarzyna Plak
1
, Angela Jacobi
1
, Nicole Töpfner
1,2
, Jochen Guck
1
.
1
Biotechnology Center, Technische Universität Dresden, Dresden, Germany,
2
University Clinic
Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
During the last decades, tools for rapid characterization of large cell quantities have become
indispensable not only for basic research but also clinical diagnostics. The gold standard for cell
characterization is flow cytometry. Its success is closely tied to the availability of fluorescent
labels. But what if there is no molecular marker known for the cells of interest? Or if the label
changes cell function? Or cells shall be used for transplantation? As an attractive alternative,
deformability cytometry exploits cell mechanics as a sensitive, inherent, label-free functional
marker, but lacks the specificity provided by a fluorescent signal. Here we present real-time
fluorescence deformability cytometry (RT-FDC), the ideal, combined system. It facilitates
fluorescence detection as in conventional flow cytometry, extended by 1D analysis of spatial
information encoded in the fluorescence pulse shape, and adds bright field imaging for
mechanical phenotyping of single cells — all in real-time at rates of 100 cells/s. We show utility
of RT-FDC for the most common fluorescent labels: Fluorescent surface markers (CD34) are
used to separate human hematopoietic stem and progenitor cells (HSPCs) from an unpurified
apheresis sample as harvested for bone marrow transplantations. Membrane permeant dyes
identify reticulocytes by their ribonucleic acid (RNA) content in a blood sample. And
endogenously expressed fluorescent proteins (FUCCI) reveal cell cycle phases in an
unsynchronized sample of retinal pigment epithelial cells (RPE1). In addition, we can now also
directly correlate mechanical characteristics with fluorescence intensity and localization for each
single cell to improve correct classification. In future, this combined approach could establish
mechanical phenotyping as equivalent to fluorescent labeling, or even identify subpopulations
invisible to molecular labels. RT-FDC is destined to find wide-spread utilization and will help to
further improve the applicability of flow cytometry.