Biomaterial Database

Electroabsorption and Stark Fluorescence Spectroscopies of Thioflavin T. 2023

Ahatashamul Islam, and Yudai Kikuchi, and Toshifumi Iimori

Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido050-8585, Japan.

Thioflavin T (ThT) is a typical fluorescent marker for detecting the formation of amyloid fibrils, because its fluorescence intensity increases by more than 2 orders of magnitude upon complexation with the fibrils. Strong electrostatic fields on protein surfaces are known to be a significant factor in chemical reactions and biological functions. Therefore, ThT bound to amyloid fibrils must experience strong electric fields. This study employed electroabsorption and Stark fluorescence spectroscopies to clarify the effects of external electric fields on the photophysics of ThT. The absorption spectrum shows two bands ascribed to locally excited (LE) and charge transfer (CT) states. Coupling between the LE and CT states is enhanced in the presence of an external electric field, resulting in fluorescence quenching. The electric field strength of the amyloid fibril surface was inferred from the fluorescence quenching efficiency of ThT.

UI	MeSH Term	Description	Entries
D005453	Fluorescence	The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
D005456	Fluorescent Dyes	Chemicals that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.	Flourescent Agent,Fluorescent Dye,Fluorescent Probe,Fluorescent Probes,Fluorochrome,Fluorochromes,Fluorogenic Substrates,Fluorescence Agents,Fluorescent Agents,Fluorogenic Substrate,Agents, Fluorescence,Agents, Fluorescent,Dyes, Fluorescent,Probes, Fluorescent,Substrates, Fluorogenic
D000682	Amyloid	A fibrous protein complex that consists of proteins folded into a specific cross beta-pleated sheet structure. This fibrillar structure has been found as an alternative folding pattern for a variety of functional proteins. Deposits of amyloid in the form of AMYLOID PLAQUES are associated with a variety of degenerative diseases. The amyloid structure has also been found in a number of functional proteins that are unrelated to disease.	Amyloid Fibril,Amyloid Fibrils,Amyloid Substance,Fibril, Amyloid,Fibrils, Amyloid,Substance, Amyloid
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D052160	Benzothiazoles	Compounds with a benzene ring fused to a thiazole ring.