Transwells

Transwell is a brand name for a type of cell culture insert widely used in biological research. These inserts are typically cylindrical chambers with a permeable membrane at the bottom. They are designed to fit inside a larger well of a multi-well plate, creating two separate compartments within the same physical well. The membrane separating these compartments has pores of a specific size, allowing for the passage of soluble molecules but preventing cell migration between the compartments.

The primary application of Transwells is to study cell-cell interactions and the effects of soluble factors on cell behavior. Researchers can seed cells in the upper insert and a different cell type or treatment in the lower well, or vice versa. This setup allows for the investigation of paracrine signaling, where cells in one compartment release signaling molecules that affect cells in the other. It is also used to model biological barriers, such as the blood-brain barrier or the intestinal epithelium, by culturing specific cell types on the Transwell membrane.

The pore size of the Transwell membrane is a critical parameter, chosen based on the experimental requirements. Smaller pore sizes might allow passage of small molecules like cytokines, while larger pore sizes can permit the migration of cells. Transwell systems are employed in diverse research areas, including immunology, cancer biology, neuroscience, and drug discovery, to assess cell migration, invasion, differentiation, and the permeability of various biological barriers.