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Cell viability studies. Sepideh Khoshnevis. The Goal. To distinguish live cells from dead and apoptotic cells in order to calculate the the percentage of viable cells for each experiment. Cell viability study. Trypan blue studies Finding data for a small population - PowerPoint PPT Presentation
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Cell viability studies
Sepideh Khoshnevis
The Goal
• To distinguish live cells from dead and apoptotic cells in order to calculate the the percentage of viable cells for each experiment
Cell viability study
• Trypan blue studies– Finding data for a small population– a good first order approximation
• Flow cytometry– Processing a large volume of data in a
reasonable time
BD FACSCalibur
How does flow cytometer work?
• It is made up of three systems– Fluidics– Optics
• Laser• Filters
– electronics
introduction to flow cytometry, BD biosciences
fluidics
• Hydrodynamic focusing
introduction to flow cytometry, BD biosciences
Light Scatter
• Forward scatter (FSC)– Proportional to cell size
• Side scatter (SSC)– Proportional to cell granularity or internal
complexity• FSC vs. SSC plot
– Isolating mixture of cell population
Differentiation of cell types
introduction to flow cytometry, BD biosciences
Fluorescence
• Fluorescent dyes• Fluorochrome conjugated antibodies
Optical bench diagram
introduction to flow cytometry, BD biosciences
Signal detection
• When the particles enters the laser beam light signal is being produced
• Light is converted to voltage by photodetectors– Photodiode – Photomultiplier tube
• Size of voltage pulse depends on the number of photons detected
• The height of the voltage pulse dictate what channel it falls under
Creation of voltage pulse
Data display
• Histogram• Dot plots• Multi dimensional plots
Current protocols in cytometry
Current protocols in cytometry
Current protocols in cytometry
Gating
• Isolating the population of interest– Cluster analysis
• Further analysis of a subpopulation