Details

Autor(en) / Beteiligte

• Gustafsson, Camilla
• Shirani, Hamid
• Leira, Petter
• Rehn, Dirk R.
• Linares, Mathieu
• Nilsson, K. Peter R.
• Norman, Patrick
• Lindgren, Mikael

Titel

Deciphering the Electronic Transitions of Thiophene‐Based Donor‐Acceptor‐Donor Pentameric Ligands Utilized for Multimodal Fluorescence Microscopy of Protein Aggregates

Ist Teil von

• Chemphyschem, 2021-02, Vol.22 (3), p.323-335

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Anionic pentameric thiophene acetates can be used for fluorescence detection and diagnosis of protein amyloid aggregates. Replacing the central thiophene unit by benzothiadiazole (BTD) or quinoxaline (QX) leads to large emission shifts and basic spectral features have been reported [Chem. Eur. J. 2015, 21, 15133‐13137]. Here we present new detailed experimental results of solvent effects, time‐resolved fluorescence and examples employing multi‐photon microscopy and lifetime imaging. Quantum chemical response calculations elucidate how the introduction of the BTD/QX groups changes the electronic states and emissions. The dramatic red‐shift follows an increased conjugation and quinoid character of the π‐electrons of the thiophene backbone. An efficient charge transfer in the excited states S1 and S2 compared to the all‐thiophene analogue makes these more sensitive to the polarity and quenching by the solvent. Taken together, the results guide in the interpretation of images of stained Alzheimer disease brain sections employing advanced fluorescence microscopy and lifetime imaging, and can aid in optimizing future fluorescent ligand development. Fluorescent biomarkers: The introduction of donor‐acceptor‐donor moieties in luminescent conjugated oligothiophenes gives a drastic shift in spectroscopic profile. This opens up for designing novel fluorescent biomarkers that can classify different types of amyloid folds and differentiate different morphological protein topologies.