Impact of solution velocity on doxorubicin mobility and interaction behavior in carbon nanotube nanocarriers: A molecular dynamics study

The influence of solution velocity on the transport and interaction behavior of a carbon nanotube (CNT) nanocarrier loaded with doxorubicin (DOX) was investigated using molecular dynamics simulations. Imposed velocities ranging from 0.001 to 0.005 Å/fs (approximately 100–500 m/s) were used as computational accelerations to examine how flow intensity modifies nanoscale thermodynamic and mechanical responses of the CNT–DOX system. Rather than directly simulating physiological release kinetics, the study evaluates mobility indicators and trends in interaction energy that reflect release tendency. Increasing velocity reduced the maximum local atomic density from 0.0035 to 0.0030 atoms/ų, indicating enhanced molecular dispersion. A moderate temperature rise (380.65–390.28 K) and a slight increase in shear stress (3.16–3.29 Pa) were observed due to kinetic-to-thermal energy conversion. The mean-squared displacement and root-mean-square deviation increased by approximately 9.8 % and 5.1 %, respectively, confirming enhanced translational mobility and structural rearrangement under stronger flow conditions. The center-of-mass separation between DOX and CNT increased from 9.35 to 10.41 Å, while binding energy became less negative (−1.05 to −0.88 kcal/mol), indicating weakened intermolecular attraction. These findings demonstrate that elevated flow intensity enhances DOX mobility and reduces effective drug–carrier interactions at the molecular scale. Although scaled velocities were employed to accelerate transport processes within atomistic time limits, the observed trends provide mechanistic insight into how hydrodynamic effects influence drug–nanocarrier interaction behavior rather than establishing quantitative in vivo release rates.