Suspension in vitro refers to a method of growing cells or microorganisms in a liquid culture, where they are suspended in the culture medium rather than attached to a solid surface (as in adherent cell cultures). In suspension cultures, cells are grown in stirred liquid media in which they form aggregates or clumps, rather than adhering to a solid substrate.

Suspension cultures are commonly used for the large-scale production of cells or microorganisms, such as in biomanufacturing or for the production of vaccines. They can also be used for studying the growth and behavior of cells in a three-dimensional environment or for studying the interactions between cells in a more natural setting.

Suspension cultures can be challenging to work with as the cells are not fixed in place, and the culture conditions must be carefully controlled to ensure optimal growth and viability. However, they have several advantages over adherent cultures, such as the ability to easily scale up the culture volume and the potential to produce a higher yield of cells or microorganisms.