Green reduced graphene oxide functionalized 3D printed scaffolds for bone tissue regeneration

Abstract

The incorporation of reduced graphene oxide (rGO) nanomaterials into scaffolds structure can be explored to enhance the properties of these 3D matrices in bone regeneration applications. However, the weak water solubility and poor colloidal stability of rGO have hindered its incorporation in blends aimed to produce scaffolds by 3D printing. Furthermore, rGO is generally obtained by treating graphene oxide (GO) with hydrazine hydrate, which is a highly hazardous reducing agent. To overcome these problems, herein a novel environmentally-friendly method was developed to assemble 3D printed scaffolds incorporating rGO. Such was achieved through the in situ reduction mediated by l-Ascorbic acid of the GO already present on tricalcium phosphate/gelatin/chitosan scaffolds. The scaffolds functionalized with rGO through the in situ method (TGC_irGO) displayed enhanced wettability and improved mechanical properties without impairing their porosity when compared to their equivalents functionalized with GO and non-functionalized scaffolds (TGC_GO and TGC, respectively). Moreover, the TGC_irGO scaffolds displayed an improved calcium deposition at their surface and an enhanced alkaline phosphatase (ALP) activity, along 21 days of incubation. Additionally, scaffolds also displayed antimicrobial activity without compromising osteoblasts’ viability and proliferation. Such features reveal the potential of the TGC_irGO scaffolds for bone tissue regeneration applications.