Efficient energy transfer from pyrene to perylene assembled inside DNA duplex.

Area of Science:

• Biochemistry
• Molecular Biology
• Organic Chemistry

Background:

• Enhancing the apparent Stokes' shift of fluorescent molecules is crucial for advanced imaging and sensing applications.
• DNA nanotechnology offers a versatile platform for precise arrangement of functional molecules.
• Förster Resonance Energy Transfer (FRET) is a key mechanism for energy transfer between molecules.

Purpose of the Study:

• To increase the apparent Stokes' shift of perylene using pyrene as a donor within a DNA duplex.
• To optimize FRET efficiency by controlling the proximity and number of pyrene donors relative to the perylene acceptor.
• To investigate the impact of DNA structure on intermolecular interactions and energy transfer.

Main Methods:

• Assembly of pyrene (donor) and perylene (acceptor) within a DNA duplex.
• Utilized D-threoninol to introduce multiple pyrene donors near perylene.
• Incorporated natural base pairs to mediate distance and suppress undesired interactions.
• Spectroscopic analysis (excitation and emission) to quantify FRET efficiency and Stokes' shift.

Main Results:

• Achieved efficient FRET between pyrene donors and a perylene acceptor within a DNA duplex.
• Observed strong perylene emission at 495 nm upon excitation of pyrene at 345 nm.
• Demonstrated a significant apparent Stokes' shift of 115 nm with high FRET efficiency (Phi>1).
• Found that increasing pyrene donors beyond two did not improve perylene fluorescence due to the limited Förster radius.

Conclusions:

• DNA duplexes can effectively mediate FRET between pyrene and perylene to achieve a large apparent Stokes' shift.
• Precise control over donor-acceptor arrangement within DNA is key to optimizing energy transfer.
• The Förster radius of pyrene limits the efficiency of FRET when multiple donors are used.