Comparative study of the therapeutic potential of C24, C32, B12N12, and B16N16 nanocages as drug delivery carriers for delivering an erlotinib derivative: DFT and QTAIM investigations†

Abstract

The use of nanostructures as drug delivery vehicles for a wide range of anticancer medications to lessen their severe side effects by delivering them to the targeted tumor cell location is presently a broadly studied innovative biomedical application of different nanostructures. To investigate the capability of C₂₄ and C₃₂, B₁₂N₁₂, and B₁₆N₁₆ nanocages as nanocarriers for delivering the methyl erlotinib molecule, we conducted density functional theory (DFT) computations using the M06-2X/6-311G(d,p) and M06-2X/6-31G(d) levels of theory. The calculation of the adsorption energy of methyl erlotinib on the nanocages was performed in aqueous and gaseous phases. The adsorption energy values associated with the interaction between the nanocages and methyl erlotinib were negative, indicating that this interaction was exothermic in nature. The adsorption energy values in the aqueous state were higher than those in the gaseous state, suggesting a stronger interaction in the aqueous state, with the exception of the C₃₂ nanocage. Analyses of the density of states (DOS) and projected density of states (PDOS) were performed in order to examine the effect of methyl erlotinib adsorption on the electronic characteristics of selected nanocages. The findings indicated that the B₁₂N₁₂ nanocage following methyl erlotinib molecule adsorption came nearer to the Fermi level than the other nanocages examined. Calculations based on the Quantum Theory of Atoms in Molecules (QTAIM) indicated that methyl erlotinib had a weak interaction with all selected nanocages. According to the values of the adsorption energy derived from both methodologies, the interaction between methyl erlotinib and the B₁₂N₁₂ nanocage was determined to be more robust than the interaction between methyl erlotinib and the C₂₄ nanocage, while the interaction between methyl erlotinib and the B₁₆N₁₆ nanocage was also stronger than that with the C₃₂ nanocage. Notable variations in the ΔE_g values were detected for methyl erlotinib@B₁₂N₁₂ and methyl erlotinib@B₁₆N₁₆ across all methods, suggesting that the conductivity of these two nanostructures improved more significantly following the adsorption of methyl erlotinib than that of other nanostructures. Consequently, the B₁₂N₁₂ and B₁₆N₁₆ nanocages can function as nanosensors for methyl erlotinib.