Figure 1

Mass-to-charge-ratio spectra of the DNA- and RNA-functionalized SWCNTs measured by TOF-SIMS. The DNA-functionalized SWCNTs shows four peaks C, T, A, and G (a) whereas the RNA-functionalized SWCNTs show four peaks C, U, A, and G (b). The peak positions of the ionized nucleotides are as follows: C (C₄H₄N₃O^-, Cyt-H) at 110.03, U (C₄H₃N₂O₂^-, Ura-H) at 111.02, T (C₅H₅N₂O₂^-, Thy-H) at 125.03, A (C₅H₄N₅^-, Ade-H) 134.04, and G (C₅H₄N₅O^-, Gua-H) at 150.04.