Related Experiment Video
Updated: Jan 22, 2026

Transport of Surface-modified Carbon Nanotubes through a Soil Column
Published on: April 2, 2015
Controlled Patterning of Carbon Nanotube Energy Levels by Covalent DNA Functionalization
Yu Zheng1, Sergei M Bachilo1, R Bruce Weisman1,2
1Department of Chemistry and the Smalley-Curl Institute , Rice University , Houston , Texas 77005 , United States.
Abstract:
Each structural form of single-wall carbon nanotube (SWCNT) has specific electronic and optical properties, but it has not been possible to achieve spatial or energetic modulation of those properties in controllable ways. We present here a simple method for using chemical reactions with single-stranded DNA (ssDNA) to accomplish such modulation. When aqueous suspensions of SWCNTs coated with ssDNA are exposed to singlet oxygen under ambient conditions, the nanotubes selectively form covalent bonds to the guanine nucleotides. This locally modulates semiconducting SWCNT energy levels and red-shifts their emission wavelengths by up to 10%. Both the magnitude and spatial pattern of these shifts can be controlled by selecting the nucleotide sequence used to coat the nanotubes. Biomedical, optoelectronic, and single-photon emission applications are foreseen.
Related Concept Videos
Covalent Bonds
Covalent Bonds
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally,...
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Network Covalent Solids
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
Covalent Bonding and Lewis Structures
Conservation of Energy in Control Volume
For steady flow systems, the time derivative of the stored energy becomes zero since there is no energy accumulation within the control volume. This simplifies the energy equation to:

