Kelvin Probe Force Microscopy of Single-walled Carbon Nanotubes Modified with DNA or Poly(ethylene glycol)

Abstract

Abstract Kelvin probe force microscopy (KPFM) of DNA–single-walled carbon nanotube (SWNT) hybrids was performed for the first time. KPFM images indicated that the hybrids had a negative surface potential relative to a Au–Pd alloy surface. In contrast, the surface potential of SWNTs modified with poly(ethylene glycol) (PEG–SWNTs) was positive even after they were wrapped by DNA. Modification with covalent bonding may have a significant effect on the potential. The results suggest a possible way to distinguish variously modified SWNTs through KPFM observation.