The following post will cover information about flow cytometry and coulter (conductive) counter.
Coulter counter (conductivity counter)
Coulter counter was invented by Wallace H. Coulter as an automated blood cell counter which consists of two chambers – sample chamber and reference chamber. Both chambers have electrolyte solution but the sample chamber contains nanoparticles of which pass through an aperture connecting two electrodes and cause a change in conductivity. This change is then measured for analysis. The coulter counter is primarily used to analyze blood counts, specifically to count the number of white and red blood cells.[1]
Flow cytometry
Flow cytometry is a technique used to detect and measure not just physical but also chemical characteristics of cells. In terms of physical features, cell size and granularity are measured. Sheath fluid helps suspended cells to gather in the center of the tube and form a core stream for every cell to flow under consistent environment. This process is called hydrodynamic focusing. There are three major components to focus on – a fluidic system, an optical system and electronics system.[2]
Fluidics system : The fluidics system plays an important role when cells flow down the tube one by one at a constant speed. Sheath fluid is used to gather cells at the center of the tube and form a core stream for every cell to flow at the same speed. This technique is called the hydrodynamic focusing. Each cell that flows through the tube is then sorted.[2]
Optics system : The optics system is where interrogation point occurs, which is a place of cell and laser interaction. As the cell passes through, the size (forward scatter) and granularity (side scatter) of a cell can be determined. The larger the cell, the more scattered the light.[2]
Electronics system : Once the characteristic of cells has been determined, the data gathered from the optics system will then be converted to numerical values in the electronics system.[2]
Image-based cell counter is the most commonly used automated cell counter while flow cytometry is often used to check performance of other automated cell counters by comparing results. When choosing your own automated cell counter, it is recommended to consider few factors as mentioned before.
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References:
1. Singh, Ashok K. Engineered Nanoparticles : Structure, Properties and Mechanisms of Toxicity. Amsterdam ; Boston, Elsevier/Ap, 2016.
2. Cossarizza, Andrea, et al. “Guidelines for the Use of Flow Cytometry and Cell Sorting in Immunological Studies.” European Journal of Immunology, vol. 47, no. 10, Oct. 2017, pp. 1584–1797, 10.1002/eji.201646632.
Thought about getting your own automated cell counter? We'll help you choose the right one.
An automated cell counter
Analysis time | < 20 seconds/test |
Dye | Trypan blue |
Cell type | Cell line (clumped cell, single cell) |
Measuring range | 1x10E4 to 1x10E7 cell/mL |
The world's fastest automated cell counter
Analysis time | < 1 second (manual focus); < 10 seconds (auto focus) |
Dye | Trypan blue |
Cell type | Cell line (clumped cell, single cell) |
Measuring range | 1x10E4 to 2x10E7 cell/mL |
A high-throughput automated cell counter
Analysis time | 3 minutes / 48 tests |
Dye | Trypan blue |
Cell size range | Detectable: 1 - 85 μm Optimal: 5 - 80 μm |
Measuring range | Detectable: 1x10E4 to 2x10E7 cells/mL Optimal: 1x10E5 to 1x10E7 cells/mL |
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