Prepare sample
To obtain the best results, follow these recommendations:
• Ensure that the cell sample is homogeneously mixed.
• The measurement range extends from 1 × 10
4
–1 × 10
7
cells/mL, but the optimal
range is 1 × 10
5
–4 × 10
6
cells/mL.
• For accurate results in cell viability assays, ensure that the counting area is
covered with the cell suspension and count the cells immediately after staining
per the assay protocol.
• Do not press the optical surfaces of the chamber slides. Hold the slides by the
edges.
• Take care to avoid forming bubbles in the sample.
• Sterile filtering and centrifugation can be used to remove precipitates common
within trypan blue solutions. Alternatively, avoid mixing and vortexing trypan
blue stock solutions to allow precipitates to remain at the bottom of tube, thereby
promoting more accurate cell counts. Also, precipitates can be reduced by gentle
heating at 37°C for 10 minutes.
1.
Prepare the sample by adding 10 µL of your cell suspension to 10 µL of 0.4%
trypan blue stain. Mix the sample mixture well by pipetting it up and down a
few times.
2.
Gently pipet 10 µL of the sample into the half moon-shaped sample loading area.
The sample is loaded into the chamber through capillary action.
3.
Let the sample mixture settle in the chamber for 30 seconds, and then insert the
slide into the slide port (“Instrument exterior components“ on page 11). You will
hear a soft click, if the slide is pushed in correctly.
4.
To remove the slide, push the slide gently into the instrument until it “clicks”
and a spring pushes the slide out. Grasp the slide and pull it out the rest of the
way.
Note:
After using the Countess
™
Cell Counting Chamber Slides, appropriately
dispose of them as biohazardous waste. Do not reuse the disposable chamber
slides.
Recommendations
Load Countess
™
chamber slide
Chapter 3
Getting started
Prepare sample
3
Countess
™
II FL automated cell counter User Guide
19
