The computational study of the γ-Fe2O3 nanoparticle as Carmustine drug delivery system: DFT approach.

In the present study, it is attempted to scrutinize the properties of the maghemite nanoparticle as a Carmustine drug delivery system by means of the density functional theory calculations regarding their geometries, adsorption energies, vibrational frequencies, and topological features of the electron density. Based on the density functional theory results, it is found that the interaction between Carmustine drug molecule and maghemite nanoparticle is weak; so that, the adsorption of the Carmustine drug is typically physisorption. It is also found that the intermolecular hydrogen bonds between the drug and the nanoparticle play the significant role in the stability of the physisorption configurations. The nature of the intermolecular interactions has been explored by calculation of the electron densities and their Laplacian at the bond critical points using Atoms-in-Molecule theory. Moreover, natural bond orbital analysis indicates that the Carmustine molecule can be adsorbed on the nanoparticle surface with a charge transfer from the Carmustine drug to the nanoparticle.