DFT insights into the adsorption performance of the anti-cancer drug nitrosourea on graphene/boron nitride heterostructures

Density functional theory was utilized to investigate the adsorption strength, electronic characteristics, and solvent effects between Nitrosourea (NU) and pristine Graphene (GP) and Boron Nitride (BN) nanosheets and their two heterostructures, such as BN/GP (heterostructure-1, H1) and GP/BN (heterostructure-2, H2), in both air and water media. Our results showed that NU was physically adsorbed on pristine GP and BN surfaces, with adsorption energies ranging from −0.59 to −0.34 eV and minimal charge transfer of about 0.006–0.021 e, indicating stable non-covalent interactions. The incorporation of GP or BN heterostructures significantly enhanced sensitivity, with adsorption energies up to −1.09 eV in water and −0.61 eV in air, while maintaining the structural integrity of selected complexes. The adsorption of NU decreased the energy gap of the nanosheets, for example, from 4.38 to 2.36 eV in BN and from 1.85 to 1.51 eV in GP/BN (H2), indicating increased conductivity and reactivity. Quantum descriptors such as chemical potential and electrophilicity indicate higher reactivity while maintaining stability for drug delivery. Furthermore, after NU adsorption, the increase in dipole moments and changes in work function, especially in water media, indicate enhanced polarity and solubility. This study emphasizes the potential of GP and BN nanosheets as efficient carriers for anticancer drugs, especially in their heterostructure forms. Among all the nanosheets examined, the GP/BN(H2) nanosheet exhibited the strongest adsorption, good structural stability, and enhanced dipole moment, suggesting it is a promising candidate for NU delivery.