MemBrite™ Fix Cell Surface Staining Kits provide a convenient way to visualize cell boundaries in multicolor staining experiments. Staining is rapid and uniform, with a wide choice of colors. MemBrite™ Fix dyes covalently label the surface of live cells. The staining withstands fixation and permeabilization for subsequent immunofluorescence staining.
Original CellBrite™ Cytoplasmic Membrane Stains are lipophilic carbocyanine dyes. These dyes undergo an increase in fluorescence when they insert into lipid bilayers. Lipophilic carbocyanine dyes stably label the plasma membrane and other intracellular membranes of cells. They also can be used to stain fixed cells or artificial lipid bilayers. CellBrite™ cytoplasmic membrane stains are lipophilic carbocyanine dyes. These dyes undergo an increase in fluorescence when they insert into lipid bilayers. Lipophilic carbocyanine dyes stably label the plasma membrane and other intracellular membranes of cells. They also can be used to stain artificial lipid bilayers. Immediately after staining cultured cells, the dyes primarily localize to the plasma membrane. If cells are cultured over time after staining, the labeled membranes are internalized and staining gradually becomes mostly intracellular.
Lipophilic carbocyanine dyes like our original CellBrite™ Cytoplasmic Membrane Stains have been used to stain neuronal cells in culture for several weeks, and in vivo for up to a year (see note below). The dyes do not appreciably affect cell viability, and do not readily transfer between cells with intact membranes, allowing cell migration and tracking studies in mixed populations. Staining with the covalent stains CellBrite™ Fix and MemBrite™ Fix lasts up to 48 hours in tissue culture cells (see note below).
Note: Over time, all cell surface stains will be internalized and become intracellular as membranes turn over by endocytosis. The rate of internalization may vary by cell type, rate of membrane turnover, and rate of cell division. In immortalized cells in culture, most of the surface staining becomes internalized over the course of about 24 hours for CellBrite™, CellBrite™ Fix, and MemBrite™ Fix stains.
For an alternative stable and fixable stain for long term cell tracking or tracking cells in mixed cultures, see our ViaFluor® SE Cell Proliferation Dyes. These dyes covalently label intracellular proteins throughout the cell and are non-toxic and fixable.
Biotium’s CellBrite™ Cytoplasmic Membrane Dyes are dye delivery solutions that can be added directly to normal culture media to uniformly label suspended or adherent cells in culture. The PKH dyes are structurally related dyes for cell membrane labeling. But unlike CellBrite™, labeling with PKH dyes requires multiple steps and subjects cells to an iso-osmotic mannitol loading medium that can negatively affect cell membrane integrity and viability.
CellBrite™ Fix dyes also feature rapid and simple labeling in isotonic buffer. Cells can be fixed and permeabilized after labeling with CellBrite™ Fix, unlike original CellBrite™ dyes or PKH dyes, which don’t tolerate detergent.
Unique kits allow you to conveniently image cell boundaries
Rapid, uniform live cell surface staining
Covalent labeling can be fixed & permeabilized for IF staining
Stain yeast and gram-positive bacteria
Choose from 12 bright & photostable dye colors from blue to near-IR
Dye options for super-resolution and other specialized imaging applications
MemBrite™ Fix Cell Surface Staining Kits are designed for covalently staining the surface of live cells to conveniently visualize cell boundaries in immunofluorescence experiments. MemBrite™ Fix are new covalent cell surface stains that react irreversibly with cell surface proteins for staining that can withstand formaldehyde or alcohol fixation, and detergent permeabilization. Unlike lectins such as WGA, which bind specific targets that may vary between cell types, MemBrite™ Fix dyes react widely with cell surface proteins. MemBrite™ Fix staining is rapid and non-toxic to cells, and because MemBrite™ Fix dyes are highly water soluble, they stain cells much more evenly than traditional lipophilic membrane dyes like DiO, DiI, PKH, Vybrant®, or CellMask™.
MemBrite™ Fix staining kits also can be used to stain yeast and gram-positive bacteria, but not gram-negative bacteria. See our Cellular Stains Table for more information on how our dyes stain various organisms.
MemBrite™ Fix Staining Kits belong to Biotium’s line of novel cell surface stains that include CellBrite™ Fix Membrane Stains. CellBrite™ Fix Membrane Stains are fluorogenic dyes that rapidly accumulate in the plasma membrane, where they react covalently with the cell surface. CellBrite™ Fix stains require only a single staining step compared to MemBrite™ Fix staining, which is a two-step protocol. On the other hand, MemBrite™ Fix dyes are available with a wider selection of colors. MemBrite™ dyes do not associate with lipids in membranes, and consequently have lower cytoplasmic background after detergent permeabilization compared to CellBrite™ Fix.
Selecting a MemBrite™ Fix Dye
Several MemBrite™ Fix dyes have been validated in super-resolution imaging applications or 2-photon microscopy. MemBrite™ Fix-ST dyes are recommended for super-resolution imaging by STORM. MemBrite™ Fix or MemBrite™ Fix-ST dyes can be used for standard microscopy applications; however, MemBrite™ Fix dyes are generally more photostable than MemBrite™ Fix-ST dyes. See the MemBrite™ Fix Product Table below for details.
Tips for Success
Note that MemBrite™ Fix dye stain dead cell more intensely than live cells. With prolonged dye incubation, or if cells are cultured after staining, the dye also will be internalized by endocytosis, resulting in labeling of intracellular vesicles. Please see our Tech Tip: Five Steps for Success with Membrane and Surface Stains for tips on staining and imaging (step 5) with MemBrite™ Fix.
MemBrite™ Fix dyes are designed to be fixed shortly after staining. With prolonged dye incubation, or if cells are cultured after staining, the dyes will be internalized by endocytosis, resulting in labeling of intracellular vesicles. By 24 hours after staining, most of the dye will be localized inside the cell, not on the cell surface. For long-term visualization of cell morphology in culture, our stable, non-toxic ViaFluor® SE Cell Proliferation Kits may be a more suitable alternative. ViaFluor® SE dyes covalently label cells throughout the cytoplasm and can be tracked for several days or longer by microscopy or flow cytometry. See our Tech Tip: Using ViaFluor® SE Stains for Cell Tracing and Co-Culture to learn more.
1. Kit size based on 200 uL reaction volume, actual number of reactions depends on sample size.
2. MemBrite™ Fix dyes are named for their Abs/Em maxima. Download the Product Information Sheet for spectra.
3. MemBrite™ Fix-ST 681/698 dye is reported to have better performance in STORM imaging than MemBrite™ Fix 680/700 dye.
Alexa Fluor & Texas Red are registered trademarks of Thermo Fisher Scientific; Cy Dye is a registered trademark of GE Healthcare; IRDye is a registered trademark of LI-COR Bioscience.
Vybrant is a registered trademark and CellMask is a trademark of Thermo Fisher Scientific.
CellBrite™ Cytoplasmic Membrane Labeling Kits are designed to label cell cytoplasmic membranes with fluorescent dyes, available in blue, green, orange, and red. The labeling is stable and nontoxic, suitable for long-term tracking of cells.
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.
Biotium’s CellBrite™ NIR Cytoplasmic Membrane Dyes are ready-to-use dye delivery solutions that can be added directly to normal culture media to uniformly label cells in suspension or adherent cultures.
Paraformaldehyde, 4% in PBS is a ready-to-use fixation solution for cells or tissues. It is electron microscopy-grade paraformaldehyde dissolved in pH 7.4 PBS, and is stabilized by packaging under argon with no methanol added.