Application of Zinc oxide nanostructures as a promising nanocarriers for ۵-ALA in drug delivery system based on DFT-MD simulations

We have examined the interactions between ۵‒aminolevulinic acid (ALA) drug and ZnOnanostructures using DFT method. In the context of the dispersion corrected PBE technic, theenergetics, charge transfer, electronic structure and equilibrium geometries have beenestimated.The ZnO nanostructures showed promising performance in the ALA drugfunctionalization, taking into account the interaction energy values. The band gap is almostremained unchanged for both of the substrates under consideration after ALA adsorption, and thesemiconductor properties of the substrates are preserved, according to the analyzed DOSsspectra. The interaction nature of ALA‒ZnO nanostructures according to the QTAIM analysiswas found as polar attraction with partial covalent bonding between O and Zn.Our DFT basedMD simulation results reveal that, in the aqueous solution, ALA moves toward the interiorsidewall of ZnO nanostructures and binds to the Zn atom through its O and N atoms and thehydroxyl H atom was dissociated and bind to the O atom of ZnO surface