Experimental Evidence of Single-Stranded DNA Adsorption on Multiwalled Carbon Nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Noncovalent DNA functionalization is key for dispersing carbon nanotubes (CNTs), forming DNA-CNT complexes with potential applications.
• Understanding the structure of adsorbed DNA on CNTs is crucial but remains poorly understood, especially for multiwalled carbon nanotubes (MWCNTs).
• MWCNTs present unique challenges due to their metallic nature, large size, and polydispersity, hindering experimental and theoretical studies.

Purpose of the Study:

• To investigate the structure and conformation of DNA adsorbed on multiwalled carbon nanotubes (MWCNTs).
• To address the knowledge gap regarding DNA organization at the MWCNT interface.
• To leverage dielectric spectroscopy for characterizing DNA-MWCNT complexes.

Main Methods:

• Dielectric spectroscopy (DS) was employed to analyze DNA-MWCNT complexes.
• DS is sensitive to charge distribution changes at interfaces and has been used for polyelectrolyte studies.
• Conductivity analysis of DNA-MWCNT suspensions was performed.

Main Results:

• Dielectric relaxation in the MHz range indicated DNA adsorption on MWCNTs.
• This relaxation provided insights into the conformational properties of the adsorbed DNA.
• Conductivity analysis confirmed DNA adsorption in a single-stranded conformation.
• Excess DNA reassociation did not affect the stability of the DNA-MWCNT complexes.

Conclusions:

• Dielectric spectroscopy is a valuable tool for studying DNA conformation on MWCNTs.
• DNA adsorbs onto MWCNTs in a single-stranded form.
• The findings contribute to understanding the fundamental properties of DNA-MWCNT complexes for future applications.