Technical Note 194

CellDrop Variable Chamber Height


Most automated cell counters rely on single use plastic slides with a fixed chamber height to perform cell counts. Standard dimensions of the slide enable the counter to calculate the total cells in a sample by counting the number of cells present in a known volume. CellDrop™ Automated Cell Counters do not require slides, but instead use a patented DirectPipette™ Technology developed by DeNovix Inc. This method allows users to load a sample directly into the measurement chamber formed between two parallel sapphire surfaces (Figure 1). The CellDrop is capable of setting three different chamber heights allowing greater measurement accuracy across a wider range of cell densities and sizes compared to slide-based systems.

CellDrop Automated Cell Counters include three chamber height options to accommodate a wide range of sample concentrations. Adjusting the chamber height varies the volume of sample and consequently the number of cells that are deposited on the measurement surface. The default chamber height is 100 µm which is recommended for most samples. By editing the protocol settings within a count app the chamber height can be adjusted to 50 µm for extremely dense samples or to 400 µm for very dilute samples or larger cells or particles. The smaller 50 µm chamber height can also be useful in shortening the time required for cells to settle before counting.

Figure 1 – DirectPipette™ Technology

Chamber Height Guidelines

The ability to adjust the chamber height enables direct measurement of cell densities between 7.0 x 102 and 2.5 x 107, while removing the need for time consuming dilution or concentration steps. The table below summarizes the appropriate chamber heights and sample volumes to use with different cell concentrations.

Sample Concentration (cells / mL)Chamber HeightVolume Required
7.0 x 10e2 - 1.0 x 10e5400 µm40 µL
5.0 x 10e4 - 1.0 x 10e7100 µm10 µL
1.0 x 10e7 - 2.5 x 10e750 µm5 µL

Advantages of DirectPipette™ Technology

  • Simple load, measure and wipe clean workflow.
  • No slides required.
  • No plastic waste.
  • Accurately measure across a wider range of cell densities than slide-based systems.
  • Cells or particles larger than 100 µm in diameter can be accommodated by using the 400 µm chamber height (full size range 4 to 400µm).

Revised 19 Oct 2020