Adsorption mechanism of single guanine and thymine on single-walled carbon nanotubes.

Bio-nano hybrids introduce magnificent applications of nanomaterials to various fields. The choice of carbon nanotube as well as sequence selection of the nucleic acid bases play a crucial role in shaping DNA-carbon nanotube hybrids. To come up with a clear vision for the choice of carbon nanotube and nucleic acid bases to create bio-nano hybrids, we studied the adsorption mechanism of the nucleic acid bases guanine and thymine on four different types of nanotubes based on density functional theory. Nucleic acid bases exhibit differential binding strengths according to their structural geometry, inter-molecular distances, the carbon nanotube diameter, and charge transfer. The π-π interaction mechanism between the adsorbent and adsorbate is discussed in terms of charge density profile and electronic band structure analysis.