Functionalization of graphene with single-stranded DNA

We have synthesized functionalized graphene by using direct dispersion of graphite flakes with single-stranded DNA in distilled water. The synthesized graphene-DNA complexes were investigated by using Raman spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), and time-of-flight secondary-ion mass spectroscopy (TOF-SIMS). Raman spectra exhibited typical G-band and 2D-band signatures of graphene at ~1590 cm−1 and ~2700 cm−1, respectively. TOF-SIMS result showed that the graphene layers were successfully functionalized with singlestranded DNA. Mono-layer and few-layer graphene were identified by measuring the layer thickness by using AFM and by analyzing the electron diffraction patterns from TEM measurements.