Electrostatic self-assembly of pFe(3)O(4) nanoparticles on graphene oxide: A co-dispersed nanosystem reinforces PLLA scaffolds

Cell responses and mechanical properties are vital for scaffold in bone regeneration. Fe3O4 nanoparticles with excellent magnetism can provide magnetic stimulation for cell growth, while graphene oxide (GO) nanosheets are commonly used as reinforcement phases due to their high strength. However, Fe3O4 or GO is tended to agglomerate in matrix. In present study, a novel co-dispersed Fe3O4-GO nanosystem was constructed through electrostatic self-assembly of positively charged Fe3O4 (pFe(3)O(4)) on negatively charged GO nanosheets. In the nanosystem, pFe(3)O(4) nanoparticles and GO nanosheets support each other, which effectively alleviates the p-p stacking between GO nanosheets and magnetic attraction between pFe(3)O(4) nanoparticles. Subsequently, the nanosystem was incorporated into poly L-lactic acid (PLLA) scaffolds fabricated using selective laser sintering. The results confirmed that the pFe(3)O(4)-GO nanosystem exhibited a synergistic enhancement effect on stimulating cell responses by integrating the capturing effect of GO and the magnetic simulation effect of pFe(3)O(4). The activity, proliferation and differentiation of cells grown on scaffolds were significantly enhanced. Moreover, the nanosystem also exhibited a synergistic enhancement effect on mechanical properties of scaffolds, since the pFe(3)O(4) loaded on GO improved the efficiency of stress transfer in matrix. The tensile stress and compressive strength of scaffolds were increased by 67.1% and 132%, respectively. In addition, the nanosystem improved the degradation capability and hydrophilicity of scaffolds. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Cairo University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).