Atto 550 is a fluorescent label related to the well-known dye Rhodamine 6G. The dye is designed for application in the area of life science, e.g. labeling of DNA, RNA or proteins. Characteristic features of the label are strong absorption, high fluorescence quantum yield, high thermal and photo-stability, and very little triplet formation. The dye is highly suitable for single-molecule detection applications and high-resolution microscopy.Atto 550 is a cationic dye (charge +1). As supplied Atto 550 consists of three isomers with identical absorption and fluorescence.Atto-Dye Labeled Phospholipids Sigma-Aldrich offers a variety of glycero-phospholipids carrying one or two fatty acid groups (lipophilic groups) and a phosphate ester residue (hydrophilic group). They are labeled at the hydrophilic head group. After incorporation of the phospholipid into a membrane the fluorophore is located at the water/lipid interface of the membrane. We currently provide 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), palmitoyl-sn-glycero-phosphoethanolamine (PPE), and 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine (DMPE) labeled with Atto-dyes.find more information here