Biology / sample fraction · BEGINNER LESSON
Supernatant
A supernatant is the liquid left above settled cells or particles after a sample is allowed to separate or is removed from a culture. In these sources, it is a culture fluid that can carry soluble molecules, vesicles, and other material released by cells.
What it is
A supernatant is the liquid portion taken from a sample after heavier material has been removed, settled, or spun down. In cell culture, researchers decant this liquid from the cells and then study what it contains.
[1] Supernatants derived from chemotherapy-treated cancer ... [2] Mode of Action of a Supernatant Activity from T-Cell Cultures ... - NIH [3] Supernatant Derived From Cytological Sample Preparations
What is measured in it
Scientists can measure soluble factors such as cytokines, which are small signaling proteins, and microvesicles, which are tiny membrane-bound particles released by cells. One study found that tumor supernatants contained cytokines and microvesicular bodies with RNA transcripts, and another used cytology-derived supernatants as a source of genomic material for genotyping.
[1] Supernatants derived from chemotherapy-treated cancer ... [3] Supernatant Derived From Cytological Sample Preparations
How it works in experiments
Because supernatants reflect the cells that produced them, they can transmit biological effects to other cells. For example, tumor supernatants changed signaling in endothelial cells, which are cells that line blood vessels, and increased tube-like growth; supernatants from chemotherapy-treated tumors were less angiogenic, meaning less able to promote new blood-vessel formation. In immune-cell experiments, allogeneic supernatant, meaning supernatant from a mixed lymphocyte reaction between cells from different individuals, increased B-cell responses.
[1] Supernatants derived from chemotherapy-treated cancer ... [2] Mode of Action of a Supernatant Activity from T-Cell Cultures ... - NIH
Limitations
A supernatant is not a single pure substance. It can contain many components at once, and the sources note that the roles of those components can be unclear. Its contents also depend on how the sample was handled, such as whether the cells were untreated or exposed to chemotherapy, and how the liquid was separated.
[1] Supernatants derived from chemotherapy-treated cancer ... [3] Supernatant Derived From Cytological Sample Preparations
Key supporting terms
Cytokines are signaling molecules used by cells to affect other cells. Microvesicles are small membrane-derived particles. Genotyping is reading genetic differences in a sample. Angiogenesis is the formation of new blood vessels. B-cells and T-cells are two major types of lymphoid cells involved in immune responses.
[1] Supernatants derived from chemotherapy-treated cancer ... [2] Mode of Action of a Supernatant Activity from T-Cell Cultures ... - NIH [3] Supernatant Derived From Cytological Sample Preparations
SEE THE IDEA
How a supernatant is used in study
Cells or mixed biological material are placed in culture or collected from fluid.
The liquid above cells or debris is removed as the supernatant.
Researchers test for cytokines, vesicles, RNA, or genomic material.
The supernatant may be added to other cells to see how it changes signaling or growth.
Sample separation leads to a liquid fraction that can be measured and then tested for biological activity.
A supernatant is the separated liquid fraction that carries released material from the original sample.
TRY IT YOURSELF
Test your understanding
Choose an answer, then check the explanation.
PUT IT TOGETHER
Match each concept to its meaning
Drag a label onto its description, or select a label and then select a description. This also works with a keyboard.
4 pairs to match
Sources and further reading
This general lesson was generated from public source material. It explains a concept; it does not interpret a private paper or provide medical advice.