G band Raman features of DNA-wrapped single-wall carbon nanotubes in aqueous solution and air

G band Raman spectra for DNA-wrapped single-wall carbon nanotubes (SWNTs) in aqueous solution and air have been investigated. The lower-frequency mode in the G band associated with semiconducting SWNTs is drastically suppressed by DNA-wrapping. In addition, the broad and asymmetric feature of the Breit–Wiger–Fano (BWF) line in the G band associated with metallic SWNTs is vanished by DNA-wrapping in aqueous solution. The BWF feature strongly appears again after the DNA-wrapped SWNTs are dried in air. These changes in the G band are discussed in the light of the vibrations and electronic properties in the SWNTs wrapped by DNA.