In culture methods, cell suspension refers to a type of culture where cells are suspended in a liquid medium.
To obtain single cells, a friable callus (small tissue that falls apart easily) is put in agitated liquid medium (agitation allows for gaseous exchange unlike solid medium), breaking it up. This allows for single cells to be released, which are then transferred to another fresh medium.
Cell suspension cultures have a big advantage over the stationary ones given that it allows for the cells to be uniformly bathed. Moreover, given that the medium tends to be agitated, it allows for aeration of the medium, providing gases to the cells. Given that the medium is a suspension, it also becomes easy to manipulate the contents of the culture.
Like any other culture, suspension cell culture has to be under controlled conditions, proving the cells with an ideal environment to proliferate. Once they reach about 80 percent confluence, it is time to subculture in order to ensure continued proper growth.
* 80 percent confluence refers to the state where 80 percent of the culture surface is covered with the growing cells.
In some cases, the cells in suspension may adhere on to the plastic surface of the culture flask or even form clumps. In such cases, a pipette can be used to pick these cells and expel them on to the surface of the flask and therefore away from the plastic surface. This helps obtain single cells given that they are no adhere on to the plastic surface.
Red Blood Cell Suspension
- (left: without hemolysis) red blood cell suspension (0.5% sheep RBCs in saline), seems red and opaque.
- (middle: without hemolysis) RBCs sedimented spontaneously for 60 min. Note that the supernatant is not colored.
- (right: hemolysis) RBC suspension treated with the hemolysin of S. pyogenes at 37C for 30 min, become transparent by hemolysis.