Electrostatic self-assembly of pFe3O4 nanoparticles on graphene oxide: A co-dispersed nanosystem reinforces PLLA scaffolds

Cell responses and mechanical properties are vital for scaffold in bone regeneration. Fe 3 O 4 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, Fe 3 O 4 or GO is tended to agglomerate in matrix. In present study, a novel co-dispersed Fe 3 O 4 -GO nanosystem was constructed through electrostatic self-assembly of positively charged Fe 3 O 4 ( p Fe 3 O 4 ) on negatively charged GO nanosheets. In the nanosystem, p Fe 3 O 4 nanoparticles and GO nanosheets support each other, which effectively alleviates the π-π stacking between GO nanosheets and magnetic attraction between p Fe 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 p Fe 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 p Fe 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 p Fe 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.