Examination of the adsorption mechanism of procarbazine anti-cancer drug onto the functionalized GaN nano-tube as a drug delivery vehicle: a DFT study

The impact of X-decoration (X = Si or In atom) on the procarbazine (PB) drug delivery performance of a GaN nano-tube (GaN-NT) was scrutinized using density functional theory calculations. The results demonstrated that the pristine GaN-NT was not a good choice for this drug delivery. Decoration of the Si and In atoms into the structure of the GaN-NT led to an increase in the Ad-E of PB from − 6.6 to − 29.1 and − 32.3 kcal mol−1, respectively. Based on the analysis of the partial density of states, the X atom considerably contributed to the generation of the virtual orbitals of the X-decorated GaN-NT, which showed that this atom was suitable for nucleophilic attack compared to the Ga atoms. Finally, the adsorption performance and capacity of PB increased after decorating X, which made the GaN-NT more suitable for drug delivery. A mechanism of drug release was introduced in cancerous tissues, which showed that in cancerous cells with low pH, PB was significantly protonated, which led to the separation of PB from the X@GaN-NT surface. The reaction mechanism of PB with the GaN-NT changed from covalent bonding in the natural environment to H-bonding in cancer cells with acidity.