Lectures
Flow Cytometry Course
The commonest design of flow chamber is based on a quartz cuvette (Figure 2.1). This is the flow chamber found in most commercial bench-top flow cytometers. It has good optical properties in that there is little extraneous scattered light generated and the fluorescent light can be collected over a large angle. It is also used in some cell sorters.
The diagram below shows an exit orifice. In a droplet deflection cell sorter, the stream emerges into the air. In bench top flow cytometers, the system is fully enclosed and the exit orifice is connected directly to waste; in these systems, the sheath flow will be upwards, not downwards as shown in the figure.
In a design often used in cell sorters, the interrogation point is outside the flow chamber. This system is called jet-in-air or stream-in-air . While this system has advantages for cell sorting, it has inferior optical properties. In droplet deflection cell sorters, the sheath and sample leave the flow chamber through a narrow orifice, between 50 and 100 µm diameter.
All bench top analysers, usually used in clinical laboratories, use some form of cuvette flow chamber.
A vacuum line is also fitted to the chamber so that it can be back-flushed to remove any blockage in the output orifice.
The flow cytometer