DFT studies of metal oxide nanocluster as a possible drug delivery system for mechlorethamine

This study examined the adsorption of the mechlorethamine (ME) anti-cancer drug loaded upon Mg₁₂O₁₂ nanocage using DFT: B3LYP (6-31G* and 6-311G** basis set) and B3PW91 (6-31G* basis set) calculations. To clarify the electronic, thermochemical, and structural properties of drug (ME) complexes with Mg₁₂O₁₂ nanocages, DFT calculations were combined with the Quantum Theory of Atoms in Molecules (QTAIM) study. NBO analysis revealed that the maximum stability energy of the electronic transfer of ME into Mg₁₂O₁₂ nanocavities originated from the LP(1)N27 to LP*(1)Mg5 transition with an E2 value of 17.63 kcal mol. Further, the maximum stability energy value obtained from Mg₁₂O₁₂ nanocages to the drug ME was owing to the electronic shift from LP*(1) Mg 5 to σ*C 31-H 41 orbitals compared to the drug/nanotube complex with E2 = 0.81 kcal.mol-1. Based on the QTAIM results, -G(r)/V(r) value ​​for the interaction between the H41 atom of the ME drug and the O13 atom of the nanocage [(C31-H41 (ME)…O13 (nanocage)] was about 0.37, indicating the covalent nature of the interaction. In the UV-Vis spectrum, the wavelength shift from 198 to 258 nm with the adsorption of the drug on the nanosorbent revealed a bathochromic change (red shift). The values ​​of ∇2ρ and ρ are associated with hydrogen bonds between atoms H41 and O13 (∇2ρ = 0.0602; ρ = 0.0208) as well as atoms O15 and H43 ∇2ρ = 0.0525; ρ = 0.0179). Thus, the interactions mentioned in this series are related to hydrogen bonds. Accordingly, based on the results obtained, Mg₁₂O₁₂ nanoclusters can be used as a promising carrier for ME drug delivery.