BD FACSCanto II, Reference Manual, Page: 106 / 158

106 BD FACSCanto II Flow Cytometer Reference Manual
Flow Cytometry
Flow cytometry measures certain properties of particles, such as size and internal
complexity, using light. To do this, a flow cytometer needs a method to move the
particles past a light source. It also needs a way to collect and convert the light
scattered or emitted by the particles into electrical signals. Most modern
cytometers use lasers as the light source and transport the particles under
investigation past the lasers using fluid or air.
The major systems in a cytometer that moves particles by fluid transport include
• a fluidics system
• an optical system
• an electronics system
Fluidics System
A fluidics system in a flow cytometer moves particles in fluid through a flow cell,
past a laser beam, and then into a waste tank.
Sheath Cubitainer to Flow Cell
On the BD FACSCanto II flow cytometer, a separate fluidics cart houses the
sheath cubitainer, cleaning fluid cubitainers, and the waste tank. Positive-pressure
pumps in the cart send sheath fluid past a 0.22-µm filter to a pressurized interior
reservoir within the cytometer, called the plenum. The plenum maintains a nearly
constant fluid level and dampens pump pulsation. As a result, sheath pressure
does not vary with the level of fluid in the sheath cubitainer. The plenum delivers
sheath fluid that has been filtered for air via a bubble filter to the flow cell with
minimal flow rate variations. Figure A-1 on page 107 shows the fluidics pathway
for the BD FACSCanto II system.