The plasma membrane is a thin semi-permeable membrane that separates the interior of all cells from their extracellular environment. It is comprised of a phospholipid bilayer that is embedded throughout with proteins, such as ion channels, carrier proteins and receptor proteins, that are responsible for carrying out specific membrane. It provides structural support and protection for all cells, is responsible for maintaining ionic homeostasis, and is an integral component in cell adhesion, cell-cell communication, ion conductivity and cell signaling pathways.

AAT Bioquest offers a wide range of plasma membrane labeling kits, fluorescent wheat germ agglutinin conjugates and lipophilic tracers - DiI, DiO, DiD and DiR tracers - for investigating lipid metabolism, imaging cell structures, and analyzing biophysical and cell signaling processes.

AAT Bioquest Cell Navigator^® Plasma Membrane Staining kits are designed to rapidly and uniformly label the plasma membrane in living cells without the cell-type differences exhibited by lectins. These kits, which employ our novel Cellpaint™ plasma membrane stains, may be used as a segmentation tool for high-content screening (HCS) or to stain cellular plasma membranes for standard fluorescence microscopy. The fluorescence staining in cell membranes is well-preserved after fixation with formaldehyde, enabling multiplexing with other fluorescent conjugates or proteins.

Wheat germ agglutinin (WGA) is a ~36 kDa lectin used extensivly in cell biology. Its high affinity for N-acetyl-D-glucosamine and sialic acid residues on glycoconjugates is routinely exploited for labeling the cell membranes of mammalian cells, gram-positive bacteria and yeast bud scars, as well as, skeletal and cardiac sacrolemma and fibrotic scar tissue. When conjugated to AAT Bioquest iFluor^® dyes, fluorescent WGA conjugates exhibit superior brightness, photostability and water-solubility, outperforming Alexa Fluor^® WGA conjugates and other spectrally similar conjugates. iFluor^® dye-labeled WGA are suitable for immunoassays, IHC, ELISA and Western Blot.

DiA, DiI, DiO, DiD and DiR are a family of dialkylcarbocyanines dyes used extensivly for labeling hydrophobic structures such as cell membranes, and as an anterograde or retrograde neuronal tracer in living and fixed cells and tissues. Once applied to cells, these dyes diffuse rapidly and laterally within the plasma membranes resulting in detailed uniform staining of the entire cell surface. Staining is specific as these dyes do not transfer via gap junctions or to unlabeled cells, unless the membrane of the labeled cell is disturbed. In addition to membrane staining and neuronal tracing, lipophilic carbocyanines have been successfully used in cytotoxicity assays, labeling lipoproteins, cell adhesion studies, tracing cell migration and fluorescence recovery after photobleaching (FRAP) assays.