Ferric ion crosslinking-based 3D printing of a graphene oxide hydrogel and its evaluation as a bio-scaffold in tissue engineering.

As a precursor of graphene, graphene oxide (GO) exhibits excellent mechanical, thermal, and electrical properties, besides appreciable biocompatibility in tissue engineering applications. However, the current GO-3D fabrication technology is still in need of optimization and simplification to ensure fine architecture and reasonable mechanical properties, which would further promote the performance of GO as bio-scaffolds in cell or microorganism attachment and in material transformation. To address this issue, we proposed a GO ink, with appreciable rheological properties and excellent printing performance via high-speed centrifugation and ferric ion-assisted cross-linking. A woodpile structure with controllable micro-pores was produced by micro-extrusion-based 3D printing technology followed by an optimized freeze-drying process. Cellular adhesion and viability were verified by inoculation and culture of HepaRG cells using the fabricated GO 3D structure, thus suggesting ferric ion-assisted cross-linking and controllable pore distribution for improving the performance of the GO construct as a bio-scaffold for in vitro liver tissue models.