Identification of Thioflavin T Binding Modes to DNA: A Structure-Specific Molecular Probe for Lasing Applications

Area of Science:

• Molecular Biophysics
• Spectroscopy
• Materials Science

Background:

• Thioflavin T (ThT) is a fluorescent dye commonly used to study amyloid fibrils.
• Understanding ThT's interaction with DNA is crucial for developing novel biosensing applications.

Purpose of the Study:

• To elucidate the binding mechanisms of Thioflavin T (ThT) with DNA.
• To investigate the impact of these binding modes on ThT's fluorescence properties.
• To explore the potential of ThT-DNA complexes in optical applications.

Main Methods:

• Polarized light spectroscopy, specifically linear dichroism.
• Time-resolved fluorescence spectroscopy.
• Analysis of short oligonucleotides with DNA cavities.
• Amplified spontaneous emission (ASE) generation.

Main Results:

• ThT exhibits dual binding modes with DNA: intercalation into the duplex and external binding to phosphate groups.
• Both binding modes are non-specific.
• A third binding mode within DNA cavities was observed.
• The interplay of these modes dictates the fluorescence quantum yield.
• External binding leads to fluorescence quenching via energy transfer.
• ASE was successfully generated in ThT-stained DNA films.

Conclusions:

• The binding of ThT to DNA is complex, involving multiple modes that modulate its fluorescence.
• ThT-DNA complexes show promise for developing sensitive DNA detection methods.
• ThT-stained DNA structures can be utilized in the design of bioderived microlasers.