Benzothiazole-Based Neutral Ratiometric Fluorescence Sensor for Amyloid Fibrils

Area of Science:

• Biochemistry
• Chemical Biology
• Neuroscience

Background:

• Early detection of amyloid fibrils is crucial for diagnosing neurological diseases.
• Thioflavin-T (ThT) is a standard fluorescent probe but cannot cross the blood-brain barrier for in vivo imaging.
• There is a need for novel probes with enhanced properties for amyloid detection.

Purpose of the Study:

• To synthesize and characterize a neutral Thioflavin-T derivative, 2-[2 '-Me,4 '-(dimethylamino)phenyl]benzothiazole (2Me-DABT).
• To evaluate 2Me-DABT as a fluorescent probe for amyloid fibrils, including its potential for in vivo applications.
• To investigate the binding sites and photophysical properties of 2Me-DABT in comparison to ThT.

Main Methods:

• Synthesis of the neutral Thioflavin-T derivative, 2Me-DABT.
• Spectroscopic analysis (fluorescence intensity and emission spectrum) of 2Me-DABT with amyloid fibrils.
• Fluorescence resonance energy transfer (FRET) studies to determine probe localization and separation.
• Molecular docking studies to confirm binding interactions within amyloid fibrils.

Main Results:

• 2Me-DABT demonstrated strong affinity for amyloid fibrils with increased emission intensity and a significant blueshift.
• Unlike ThT, 2Me-DABT exhibits potential as a ratiometric sensor for amyloid fibrils.
• FRET and molecular docking studies indicated that 2Me-DABT binds to the inner core of amyloid fibrils, distinct from ThT binding sites.

Conclusions:

• The neutral Thioflavin-T derivative, 2Me-DABT, is a promising candidate for amyloid fibril detection.
• 2Me-DABT's properties suggest potential for ratiometric sensing and improved in vivo imaging capabilities compared to ThT.
• Further research into 2Me-DABT could advance the diagnosis and monitoring of amyloid-related neurological diseases.