Chlormethine drug adsorption on the zinc oxide nanotube surface for drug delivery system

Zinc oxide nanotubes (ZnONTs) are a promising option for various drug delivery systems due to their non-cytotoxic and chemically stable properties. This study investigates the drug delivery capabilities and adsorption properties of ZnONTs as a delivery vehicle for the anti-cancer drug chlormethine (CM) using density functional theory (DFT) and considering solvent effects. The results indicate that the Zn atoms on the ZnONT surface are the most favorable sites for CM adsorption. The Cl atom in the chlormethine (CM) drug binds strongly to the pyramidal site of the zinc oxide nanotube (ZnONT), resulting in favorable physical adsorption. In this configuration, the Cl atom of CM interacts with a Zn atom of the ZnONT at a distance of 2.090 Å, with an adsorption energy of -20.45 kcal/mol. To explore attributes of drug-nanotube complex in the excited state, UV-vis data of interaction of CM/ZnONT system has been investigated. The maximum absorption wavelength of the drug shows a significant shift towards the red end of the spectrum when it is adsorbed on the surface of the nanotube. This suggests that the nanotube could also be used as an optical sensor to detect and monitor the presence of the drug molecule. In low pH, mechanism of drug release reveals CM can be released in cancer tissues. This research presents precise mechanism of CM interaction with ZnONT and shows that ZnONT is proper option as delivery vehicle for CM.