| DiD (1,1 - dioctadecyl-3,3, 3 - tetramethylindolecarbocyanine iodide) is a lipophilic fluorescent dye belonging to the indocyanine class of dyes. The long-chain alkyl group in DiD molecules has strong lipophilicity and can bind with the hydrophobic tail in the lipid bilayer of the cell membrane through hydrophobic interactions. The polar head of the molecule is exposed on the membrane surface, and DiD molecules can stably anchor on the cell membrane, thereby achieving fluorescent labeling of the cell membrane. DiD has very weak fluorescence before entering the cell membrane, but when it enters the cell membrane, it can be excited to produce strong far red fluorescence. The maximum excitation wavelength of DiD is 644 nm, and the maximum emission wavelength is 663 nm, usually excited by a 633 nm helium neon laser. DiD has a longer fluorescence wavelength and better tissue penetration, making it more suitable for cell tracking in deep tissue or in vivo imaging. Its long wavelength has advantages in cell and tissue staining, making it suitable for simultaneous staining of multiple fluorescent dyes with minimal interference from tissue spontaneous fluorescence. |
