Mito-laurdan bromide

Mito-laurdan (bromide) is a Fluorescent dye for mitochondrial membrane fluidity and packing measurement. It depends on membrane potential for targeting: it contains a cationic triphenylphosphonium moiety that accumulates at the inner mitochondrial membrane due to the membrane's negative potential, connected via a 3-carbon linker. As a solvatochromic dye derived from Laurdan (HY-D0080), it retains the characteristic mechanism where fluorescence emission shifts based on membrane packing: in more fluid, loosely packed membranes, greater water penetration leads to increased dipolar relaxation and a bathochromic red shift in emission, while more ordered membranes show a blue-shifted emission; these shifts are quantified using generalized polarization, calculated from emission intensities in ordered and disordered spectral windows. Its excitation wavelength is 352 nm, with emission detected in ordered (409-463 nm) and disordered (473-516 nm) spectral windows. It localizes specifically to mitochondria in HeLa cells, showing high signal overlap with MitoTracker Deep Red, and can detect changes in inner mitochondrial membrane fluidity .