The role of amino acid functionalization for improvement of adsorption Thioguanine anticancer drugs on the boron nitride nanotubes for drug delivery

Herein, density functional theory (DFT) calculations were employed to evaluate the performance of a drug delivery system for cysteine amino acid functionalized carbon nitride nanotubes (f-C₃NNTs) for Thioguanine (TG) anticancer drugs. Moreover, to compare better, pristine C₃NNTs were considered for the calculations. According to acquired results, one can realize that the process of drugs adsorption on the nanostructure has occurred spontaneously with the release of heat. It should be mentioned that f-C₃NNTs/TG complexes have interactions with the highest strength. Based on our calculations, compared with unfunctionalized C₃NNTs, f-C₃NNTs have a shorter distance of adsorption, higher adsorption capability, and higher solubility upon the adsorption of TG. Due to the polarity of all complexes, they are soluble in aqueous environments. According to the quantum molecular descriptors, f-C₃NNTs have higher reactivity compared with pristine C₃NNTs. According to thermodynamic investigations, TG molecule's interactions with f-C₃NNTs are exothermic and spontaneous. Thus, f-C₃NNTs can be considered a potential candidate for the adsorption of TG drugs as a drug delivery system.