Synthesis and characterization of zinc oxide decorated on graphene oxide: morphology selection and biological assessment

The morphology of nanomaterials as one of the physicochemical parameters plays a crucial role in determining the outcomes of interactions at the bio-nano interface. This work focuses on the biological features of graphene oxide (GO) decorated with zinc oxide (ZnO) (GO@ZnO) due to its outstanding properties with high potential to use in the biomedical field. GO@ZnO are synthesized, and the effect of seeding, temperature, and pH on the morphology of ZnO on GO substrate is evaluated by field emission scanning electron microscopy and X-ray diffraction technique. GO decorated with platelet and rod-like ZnO as GO@PZnO and GO@RZnO, respectively, are selected to investigate in vitro cytocompatibility, antibacterial activity, and interaction with human serum albumin (HSA) to put out the role of morphology. The antibacterial activity assays confirm the higher efficacy of GO@PZnO compared to GO@RZnO. However, the binding assessment indicates that HSA interaction is directly affected by the morphology of GO@ZnO so that the GO@RZnO-HSA complex is more stable than the GO@PZnO-HSA complex with a higher binding constant. Our results provide insight into how the morphology of GO@ZnO affects cell behavior, antibacterial activity, and protein complex formation. These findings are helpful to the development of GO@ZnO for future biomedical applications.