Molecular insight into adsorption affinities of Carmustine drug on boron and nitrogen doped functionalized single-walled carbon nanotubes using density functional theory including dispersion correction calculations and molecular dynamics simulation.

We report a quantum mechanics calculation and molecular dynamics simulation study of Carmustine drug (BNU) adsorption on the surface of nitrogen (N) and boron (B) doped-functionalized single-walled carbon nanotubes. The stability of the optimized complexes is determined on the basis of relative adsorption energy (ΔE). The ΔE results claim that drug molecule tends to adsorb on the nitrogen and boron doped functionalized tubes with the energy values in the range of -61.177 to -95.806 kJ/mol. Based on the obtained results, it is observed that N-doping compared with B-doping has improved more effectively drug absorption on the surface of functionalized nanotube. The results of Atoms in Molecule calculations indicate that drug adsorbs molecularly via hydrogen bonds interactions on the surface doped-functionalized carbon nanotubes. Moreover, molecular dynamics simulation is performed to investigate the dynamics behavior of the drug molecules on the nitrogen-doped functionalized carbon nanotube (f-NNT) and functionalized carbon nanotube (f-CNT). The higher average calculated electrostatic and van der Waals energies as well as higher number of intermolecular hydrogen bonds in BNU-f-NNT in comparison with BNU-f-CNT model suggest the more effectual interaction between drug molecules and nitrogen-doped functionalized carbon nanotube.Communicated by Ramaswamy H. Sarma.