Interaction site preference between carbon nanotube and nifedipine: A combined density functional theory and classical molecular dynamics study

A novel hybrid density functional theory, MPWB1K, was firstly employed to investigate static adsorptions of a nifedipine on a (10, 10) type of single-walled carbon nanotube (SWCNT), which was modeled by C200H40 and C280, respectively. For both SWCNT models the internal adsorption is more stable than the external adsorption in a range of 5.3-7.8 kcal/mol, which indicates that a nifedipine has a preference to internally adsorb on the (10, 10) SWCNT. Molecular dynamic simulations were then used to predict the dynamic behaviors of a nifedipine and the (10, 10) SWCNT system in both gas phase and aqueous solution. The classical MD simulations show that for both cases a nifedipine could spontaneously encapsulate into the SWCNT and migrate in a surprising oscillation behavior inside the SWCNT; however, both phenomena are significantly delayed in the presence of water molecules. The present study suggests that the nanotube network may be used as an efficient tool for transporting this kind of calcium channel antagonists.