5,5'-((1E,1'E)-1,4-phenylenebis(ethene-2,1-diyl))bis(2-hydroxybenzoic acid)

X-34 is a lipophilic and bright yellow-green fluorescent derivative of Congo red (HY-D0236). X-34 can be used to stain neuritic and diffuse plaques, neurofibrillary tangles (NFTs), neuropil threads, and cerebrovascular amyloid in the brain. X-34 can be used for research of Alzheimer’s disease[1].

Fluorescent, amyloid-specific dye', 'X-34 (1,4-bis(3-carboxy-4-hydroxyphenylethenyl)-benzene) is one among the small-molecule γ-secretase modulators (GSMs) involved in lowering Aβ42 levels (the 42-residue isoform of the amyloid-β peptide). X-34 has also been used to visualize intracellular immunoreactive deposits with classic amyloid fibrillar ultrastructure in living transgenic Caenorhabditis elegans animals. It is also used as a histochemical stain for determining pathological changes in Alzheimerμs disease (AD).', 'X-34 is a fluorescent, amyloid-specific dye. It binds at a different site than Pittsburgh Compound B and is a highly fluorescent marker for beta-sheet structures.

[1] Styren SD, et al. X-34, a fluorescent derivative of Congo red: a novel histochemical stain for Alzheimer's disease pathology. J Histochem Cytochem. 2000 Sep;48(9):1223-32. DOI:10.1177/002215540004800906
[2] Link CD, et al. Visualization of fibrillar amyloid deposits in living, transgenic Caenorhabditis elegans animals using the sensitive amyloid dye, X-34. Neurobiol Aging. 2001 Mar-Apr;22(2):217-26. DOI:10.1016/s0197-4580(00)00237-2