APPlications with rt-dc

Quality control of blood products

Cell types: platelets, red blood cells, stem cells

Outcome:  Using an AcCellerator system with FluorescenceModule the authors in this study approached the question of how cellular blood products like platelet concentrates, red blood cells and hematopoietic stem cells can be assessed label-free and from minimal sample volume. The authors demonstrate the application of RT-DC as a robust quality control tool to monitor the status of platelets stored at different temperature and to verify intracellular changes by nanoparticle exposition. Further, they use mechanical phenotyping to emphasize the impact of plasticizers in PVC blood bags on the rheology of red blood cells. Finally, they investigated the impact of cryoprotectants on the mechanical properties of hematopoietic stem cells. In summary the study shows that real-time deformability cytometry can be used as a label-free diagnostics with high innovative potential.
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Discern blood cell types

Cell types: whole blood  (thrombo-, lympho-, mono-. erythrocytes, baso-, eosino-, neutrophils)

Outcome: Many cell types are distinguishable by properties of their images like brightness and size. In whole blood samples, this enables the identification and further analysis of erythrocytes (red blood cells), thrombocytes (platelets) and even subpopulations of leukocytes (white blood cells) without the need of labeling or cell purification.

Resolve kinetics in neutrophil activation

Cell types: neutrophils

Outcome: High measurement rates and fast sample preparation allow for observation of kinetic processes. The plot below shows the change of mechanical properties when neutrophil granulocytes from freshly drawn blood are exposed to formyl-methionyl-leucyl-phenylalanin (fMLP). The tripeptide fMLP is released by many bacteria and signals an infection to cells of the immune system.

Characterization of artificial red blood cells

Cell types: Red blood cells

The production of therapeutic red blood cells (RBCs) for blood donation is a highly important research area. One of the major challenges is the discrimination between nucleated and enucleated RBCs. The latter still contain a cell nucleus and need to be removed from an artificial blood sample before any clinical application. Using the AcCellerator we demonstrated at throughput rates of exceeding 1,000 cells per second that our system can distinguish between both RBC types. In future the combination of our mechanical cell analysis with a label-free sorting strategy will help to produce purified artificial blood samples.

Detect changes of the cytoskeleton

Cell types: HL60

Outcome: Alterations of the cytoskeleton can be quantified through mechanical analysis. The depletion of actin microfilaments by Cytochalasin D results in a higher deformation and therefore, reduced stiffness of HL60 cells. The plot below shows the superposition of treated and untreated cells.

Investigate effects of past conditions

Cell types: hematopoietic stem cell, CD34 positive cells

Outcome: Primary human hematopoietic stem cells (HSCs), are commonly identified by the presence of the transmembrane protein CD34. The plot below compares CD34+ cells obtained from bone marrow and CD34+ cells that were mobilized into peripheral blood by the granulocyte colony–stimulating factor (G-CSF). While identical according to their CD34+ classification, HSCs derived from peripheral blood are stiffer than HSCs derived from bone marrow.

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