The Effect of Graphene Oxide on the Properties and Release of Drugs from Apatite-Polymer Composites.

The effect of graphene oxide (GO) on the structural and mechanical properties of Hydroxyapatite- Alginate (HA-Alg) based composite, as well as the ability to release the Сhlorhexidine (CНХ) and Diclofenac Sodium (DS) from it are studied. HA-Alg beads were synthesized with different GO content (0.0004 % and 0.004 %). The formation under MW irradiation of calcium-deficient HA (Ca/P  1.65) with small carbonate content is confirmed by XRD and XRF techniques. Alg acts as a dispersant and provides the uniform distribution of GO particles within the Alg matrix after sonification. GO nanoparticles in combination with cross-linked Alg macromolecules by calcium ions contribute to the enhancement of mechanical properties of the obtained beads. Distribution of GO particles in the Alg matrix enhances composites Young's modulus from 0.79 GPa in the HA-Alg sample to 1.33 GPa in the HA-Alg-GO sample. Calculated intra- and intermolecular interaction energies in the HA-Alg-GO complex confirm that the total stabilization energy consists of solvophobic interactions, van der Waals stacking energy, and H-bonds. CНX release is influenced by GO content and is primarily driven by matrix erosion. GO prolongs the release of the СHX for 48 h in a neutral medium. The release of the DS in a neutral medium is affected by GO content. In an acidic environment, DS release is controlled mainly by diffusion forces, which are slowed down by the clustering of DS through the formation of H-bonds and hydrophobic interactions between GO and DS. [ABSTRACT FROM AUTHOR]