LabWrench

CellBrite™ Fix Membrane Stains are a new class of fluorogenic membrane dyes that covalently stain the plasma membrane in live cells. They are unique among membrane stains in that they can withstand both fixation and detergent permeabilization. Available with green, red, and far-red fluorescence. 
 
CellBrite™ Fix dyes are a series of proprietary fluorophores developed by Biotium to rapidly stain the outer plasma membranes of live cells. Other membrane dyes like DiO, DiI, Vybrant® membrane dyes, CellMask™, CellVue®, or PKH dyes can be fixed with formaldehyde. But they are not compatible with detergent permeabilization or methanol fixation, because these treatments extract lipophilic dyes from membranes. In contrast, CellBrite™ Fix Membrane Stains are unique in that their surface staining can withstand permeabilization and methanol fixation, allowing plasma membrane staining to be combined with intracellular staining with antibodies. Unlike lectins such as WGA, which bind specific targets that may vary between cell types, CellBrite™ Fix dyes are general membrane stains. 
 
CellBrite™ Fix dyes are amine-reactive and are designed to accumulate at the cell membrane, where they become covalently attached to membrane proteins. As a result, surface staining is well-retained after permeabilization or methanol fixation, with only a slight increase in intracellular fluorescence compared to formaldehyde fixation alone. CellBrite™ Fix dyes are only weakly fluorescent in aqueous media but become intensely fluorescent upon membrane staining. This fluorogenic property of the dyes makes the staining very specific with low background. Due to their better water solubility, CellBrite™ Fix dyes yield much more uniform staining compared to lipophilic carbocyanine dyes like DiO and DiI. The dyes are non-cytotoxic and do not readily transfer between cells. They also can be used to stain yeast and bacteria (gram-positive or gram-negative).