Texas Red–dextran conjugate (average MW = ~70K, fixable) is a lysine-derivatized dextran intended for fluorescence-based tracing and transport studies in cells, tissues, and whole organisms. Conjugated to Texas Red (Ex/Em = 586/603 nm), it produces a bright, photostable red-orange signal compatible with standard fluorescence microscopy as well as advanced imaging modalities. The 70-kDa dextran backbone provides defined diffusional properties that support applications such as anterograde and retrograde neuronal labeling, endothelial barrier assessment, and measurements of extracellular or intracellular transport.

The presence of primary amine groups allows the conjugate to become covalently crosslinked to proteins during aldehyde fixation, ensuring that the fluorescent signal remains associated with the labeled structures through permeabilization, immunostaining, tissue clearing, and long-term storage. This fixability permits reliable correlation between the tracer distribution and additional molecular or structural markers introduced after fixation.