Trypan blue, also known as trypan blue or trypan blue, molecular formula C34H24N6Na4O14S4, molecular weight 960.81, CAS Number 72-57-1, is an anionic dye, Trypan blue can not pass through the normal intact cell membranes of living cells, so the living cells do not color, that is, the so-called refusal to dye phenomenon, and the dead cells increase the permeability of the cell membrane to allow the dye to pass through the cell membrane into the cells, so that the dead cells color blue. The increased permeability of the cell membrane of dead cells allows the dye to pass through the cell membrane into the cell, so that the dead cells are colored blue, which is the most commonly used method to detect cell viability. The loss of cell membrane integrity is usually regarded as cell death, which is opposite to the role of neutral red. Therefore, trypan blue staining can be used to distinguish live cells from dead cells very easily and quickly, and it is one of the most commonly used staining methods for dead cell identification in tissue and cell culture.

Trypan Blue Stain  is commonly used to detect the integrity of cell membranes and cell viability. Live cells are not stained blue, while dead cells are stained light blue. Trypan Blue can be phagocytosed by macrophages, so it can be used as a macrophage viability stain. 0.4% is the most commonly used concentration.