Rigid Rod-Based FRET Probes for Membrane Sensing Applications

Area of Science:

• Biophysical Chemistry
• Materials Science
• Optical Biosensing

Background:

• Lipid bilayers are crucial for cellular functions and drug delivery.
• Developing precise optical probes for membrane studies remains a challenge.
• Existing scaffolds often perturb the native lipid bilayer environment.

Purpose of the Study:

• To introduce Oligospirothioketal (OSTK) rods as a novel scaffold for optical membrane probes.
• To demonstrate the facile incorporation and minimal disturbance of OSTK rods in lipid bilayers.
• To showcase the utility of OSTK rods for constructing precisely oriented Förster resonance energy transfer (FRET) probes.

Main Methods:

• Synthesis and characterization of OSTK rods.
• Incorporation of OSTK rods into large unilamellar vesicles (LUVs).
• Labeling of OSTK rods with fluorescent dyes (coumarin and [1,3]dioxolo[4,5-f][1,3]benzo-dioxole).
• Steady-state and time-resolved fluorescence spectroscopy.

Main Results:

• OSTK rods are readily incorporated into lipid bilayers due to their hydrophobic nature.
• The high aspect ratio of OSTK rods minimizes bilayer disturbance.
• Defined labeling allows precise control over dye orientation on the OSTK scaffold.
• Demonstrated construction of FRET probes with controlled dipole orientations.

Conclusions:

• OSTK rods provide a rigid, adjustable, and minimally perturbing scaffold for optical membrane probes.
• OSTK-based probes offer precise control over dye orientation, enabling advanced FRET applications.
• OSTK rods represent a versatile toolbox for sophisticated optical biosensing.