Cells can be fixed with formaldehyde after labeling with the original CellBrite™ or CellBrite™ NIR cytoplasmic membrane dyes. Lipophilic carbocyanine dyes like CellBrite™ and CellBrite™ NIR dyes have also been used to stain cells or tissues after formaldehyde fixation. Permeabilization of cells with detergents or solvents, or mounting medium containing glycerol may adversely affect staining. Permeabilization with digitonin (10 ug/mL to 1 mg/mL) has been reported to be compatible with lipophilic carbocyanine dye staining. We’ve seen good results when formaldehyde-fixed cells are permeabilized before staining with CellBrite™ dyes (See Tech Tip: Combining Lipophilic Membrane Dyes with Immunofluorescence).
The CF® Dye WGA Conjugates can also be used to label the cell surface or plasma membrane in fixed cells/tissues or FFPE sections. On tissue sections however, the lectins would label glycoproteins on all cell membranes, external (plasma membrane) as well as internal (organelle membranes). WGA staining can also be tissue- and cell-type dependent i.e. it is based on the expression pattern of glycoproteins on the cell membranes.
CellBrite™ Fix Membrane Stains and MemBrite™ Fix Cell Surface Stains belong to a new class of membrane dyes designed to covalently label the cell surface. They can withstand fixation and permeabilization, or fixation with alcohol after labeling of live cells. CellBrite™ Fix and MemBrite™ Fix cannot be used to label the plasma membranes of fixed cells or tissues (the dyes label the cytoplasm in fixed cells).View more FAQs