A First-Principles Study of the Interaction of Aspirin with Nitrogen-Doped TiO2 Anatase Nanoparticles

First-principles calculations have been carried out to investigate the interaction of aspirin molecule with nitrogen-doped TiO2 anatase nanoparticles using the density functional theory method in order to fully exploit the biosensing capabilities of TiO2 particles. For this purpose, we have mainly studied the adsorption of the aspirin molecule on the fivefold coordinated titanium atom site of the TiO2 nanoparticles because of the more reactivity of this site in comparison with the other sits. The complex systems consisting of the aspirin molecule positioned toward the undoped and nitrogen-doped nanoparticles have been relaxed geometrically. The obtained results include structural parameters such as bond lengths and energetic of the systems. The electronic structure and its variations resulting from the adsorption process, including the density of states, molecular orbitals and the Mulliken charge transfer analysis have been discussed. We found that the adsorption of aspirin molecule on the nitrogen-doped TiO2 nanoparticles is energetically more favorable than the adsorption on the undoped ones. These results thus provide a theoretical basis and overall understanding on the interaction of TiO2 nanoparticles with aspirin molecule for applications in modeling of efficient nanomedicine carriers, biosensors and drug delivery purposes.