MB™ 680R is a bright and photostable far-red dye that emits fluorescence at about 685 nm in the borderline spectral region between far-red and near-IR. Although the absorption maximum is at around 680 nm, this dye can be sufficiently excited by the 633 or 635 nm laser. MB™ 680R dye is water soluble and pH-insensitive from pH 4 to pH 10. MB 680R is a rhodamine-based dye, and like rhodamine dyes in general, it is exceptionally photostable. The superior photostability and excellent brightness of MB 680R make the dye an ideal choice for confocal microscopy and other demanding applications.
The NHS Ester reacts specifically and efficiently with a primary amine (e.g., side chain of lysine residues or aminosilane-coated surfaces) at pH 7-9 to form a stable, covalent amide bond. The NHS ester (or succinimidyl ester) is the most popular tool for conjugating dyes to the primary amines of protein or antibody (Lys), amine-modified oligonucleotides, and other amine-containing molecules.