Molecular dynamics study on loading mechanism of chitosan into boron nitride nanotubes

Boron nitride nanotubes (BNNTs) have been considered as one of the most promising materials in drug delivery systems. It is important to understand the interaction mechanism between chitosan and BNNTs from atomic level. Herein, molecular dynamics (MD) simulation were employed to investigate the interaction mechanism and loading mechanism of chitosan into/onto BNNTs. The effect of functional group in chitosan and the diameter of BNNTs on the interaction mechanism between BNNTs and chitosan were discussed. It is found that chitosan can only absorb on the outer surface of BNNT (12,12) owing to the size of chitosan and its solvent layer. The loading process of chitosan with –NH2 group (CS_A10) into the BNNT (14,14) is much easier than that for –NH3+ group system (CS_B10). The different loading dynamics for CS_A10/CS_B10 were explained from Gibbs free energy as well as the solvation behavior of chitosan chains.