Diphenyl Blue (Trypan blue), a cell viability dye, is the most commonly used dye to identify dead cells and is used to test cell membrane integrity and cell viability[1]. Normal living cells have a complete membrane structure, which can repel trypan blue and prevent it from entering the cell; while cells with inactive or incomplete membranes have increased membrane permeability and can be stained blue by trypan blue It is generally considered that the integrity of the cell membrane is lost, that is, the cell is considered to be dead, which is opposite to the effect of neutral red. Therefore, with the help of trypan blue staining, it is very simple and fast to distinguish living cells from dead cells. Trypan blue is one of the most commonly used stains for dead cell identification in tissue and cell culture[1]. Macrophages are able to phagocytose diphenyl blue, so it can be used as a live stain for macrophages[2].
Diphenyl Blue(Trypan blue) 是一种细胞活性染料，是鉴定死细胞最常用的染料，用于测试细胞膜完整性和细胞活力[1]。正常的活细胞，胞膜结构完整，能够排斥台盼蓝，使之不能够进入胞内；而丧失活性或细胞膜不完整的细胞，胞膜的通透性增加，可被台盼蓝染成蓝色，通常认为细胞膜完整性丧失，即可认为细胞已经死亡，这与中性红作用相反，因此，借助台盼蓝染色可以非常简便、快速地区分活细胞和死细胞。台盼蓝是组织和细胞培养中最常用的死细胞鉴定染色方法之一[1]。巨噬细胞能够吞噬二苯蓝，因此它可以用作巨噬细胞的活染色剂[2]。
References:
[1]. B A Avelar-Freitas,et. Trypan blue exclusion assay by flow cytometry. 2014 Apr;47(4):307-15. doi: 10.1590/1414-431X20143437. Epub 2014 Mar 18.
[2]. Daly, M. L., DeRosa, C. A., Kerr, C., Morris, W. A., & Fraser, C. L. (2016). Blue thermally activated delayed fluorescence from a biphenyl difluoroboron β-diketonate. RSC Advances, 6(85), 81631–81635. doi:10.1039/c6ra18374c.