DiI Staining Solution

DiI (1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) is a commonly used lipophilic fluorescent dye. The long alkyl chains of the DiI molecule exhibit strong hydrophobicity, allowing them to associate with the hydrophobic core of the lipid bilayer in cell membranes through van der Waals interactions. Meanwhile, the indole ring portion is exposed to the hydrophilic surface of the membrane, interacting with the aqueous environment or the polar regions of membrane proteins, which helps prevent DiI from detaching from the membrane. Once incorporated into the cell membrane, DiI can laterally diffuse, gradually labeling the entire membrane. Upon excitation, it emits bright orange-red fluorescence, with a maximum excitation wavelength of 549 nm and a maximum emission wavelength of 565 nm. The labeling of cell membranes by DiI is reversible; in the presence of unlabeled neighboring cells, DiI can be transferred between cells through membrane contact. DiI is widely used as an anterograde or retrograde tracer for living or fixed neurons and other types of cells or tissues.