Successive Azide and DNA Functionalization for Reversible and Controlled Association of Single-Wall Carbon Nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Organic Chemistry

Background:

• Carbon-based nanomaterials offer unique properties but require effective functionalization strategies.
• Developing robust linkers is crucial for tailoring nanomaterial properties for specific applications.
• Azido groups serve as versatile handles for subsequent chemical modifications.

Purpose of the Study:

• To synthesize and characterize a novel bifunctional linker for carbon nanomaterial functionalization.
• To introduce azido groups onto single-wall carbon nanotube sidewalls.
• To demonstrate the utility of azido-functionalized nanotubes in biological applications.

Main Methods:

• Synthesis of a bifunctional linker with terminal azido and diazonium groups.
• Functionalization of (6,5)-single-wall carbon nanotubes with the synthesized linker.
• Copper-free strain-promoted azide-alkyne cycloaddition for attaching biomolecules (6-carboxyfluorescein, oligonucleotides).
• UV melting profiles and atomic force microscopy (AFM) for characterization.

Main Results:

• Successful synthesis of the bifunctional linker.
• Efficient introduction of azido groups onto single-wall carbon nanotube sidewalls.
• Demonstrated versatile functionalization with fluorescent dyes and oligonucleotides.
• Evidence of hybridization-controlled bundling-debundling equilibria in functionalized nanotube mixtures.

Conclusions:

• The bifunctional linker provides a robust and straightforward method for functionalizing carbon nanotubes.
• Azido-functionalized carbon nanotubes are suitable for diverse biological applications.
• Oligonucleotide functionalization enables controllable self-assembly of carbon nanotubes.