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Conjugated Polyelectrolytes—Conformation‐Sensitive Optical Probes for Staining and Characterization of Amyloid Deposits
Author(s) -
Nilsson K. Peter R.,
Hammarström Per,
Ahlgren Fredrik,
Herland Anna,
Schnell Edrun A.,
Lindgren Mikael,
Westermark Gunilla T.,
Inganäs Olle
Publication year - 2006
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200500550
Subject(s) - amyloid (mycology) , biophysics , polyelectrolyte , chemistry , fluorescence , protein aggregation , amyloidosis , congo red , conjugated system , in vivo , ex vivo , biochemistry , in vitro , biology , pathology , polymer , medicine , inorganic chemistry , physics , microbiology and biotechnology , organic chemistry , quantum mechanics , adsorption
Specific markers for diseases associated with protein aggregate depositions are of great interest. Here we report the use of conjugated polyelectrolytes as conformation‐sensitive optical probes for histological labeling of amyloid deposits in ex vivo tissue samples—amyloid light chains in primary systemic amyloidosis, islet amyloid polypeptide in human pancreas, and Aβ amyloid in Alzheimer's disease. Under suitable conditions, these probes bind specifically to amyloid deposits, and this is seen as an orange‐red emission from the polyelectrolyte. Furthermore, the probes emit light of different colors when bound to different amyloid deposits or other intracellular structures. This phenomenon is most probably due to differences in the protein conformation in these structures. Hence, different protein conformations will generate geometric alterations of the bound polyelectrolyte backbone, affording different emissions from the bound probe. Conformation‐sensitive probes thus provide a direct link between spectral signal and protein conformation. Finally, the probes also proved useful for ex vivo fluorescence imaging by multiphoton excitation.