Two-dimensional graphene oxide-reinforced porous biodegradable polymeric nanocomposites for bone tissue engineering

This study investigates the mechanical properties and in vitro cytotoxicity of two-dimensional (2D) graphene oxide nanoribbons and nanoplatelets (GONRs and GONPs) reinforced porous polymeric nanocomposites. Highly porous poly(propylene fumarate) (PPF) nanocomposites were prepared by dispersing 0.2 wt % single- and multiwalled SONRs (SWGONRs and MWGONRs) and GONPs. The mechanical properties of scaffolds were characterized using compression testing and in vitro cytocompatibility was assessed using QuantiFlour assay for cellularity and PrestoBlue assay for cell viability. Immunofluorescence was used to assess collagen-I expression and deposition in the extracellular matrix. Porous PPF scaffolds were used as a baseline control and porous single and multiwalled carbon nanotubes (SWCNTs and MWCNTs) reinforced nanocomposites were used as positive controls. Results show that incorporation of 2D graphene nanomaterials leads to an increase in the mechanical properties of porous PPF nanocomposites with following the trend: MWGONRs > GONPs > SWGONRs > MWCNTs > SWCNTs > PPF control. MWGONRs showed the best enhancement of compressive mechanical properties with increases of up to 26% in compressive modulus (i.e., Young's modulus), ~60% in yield strength, and ~24% in the ultimate compressive strength. Addition of 2D nanomaterials did not alter the cytocompatibility of porous PPF nanocomposites. Furthermore, PPF nanocomposites reinforced with SWGONRs, MWGONRs, and GONPs show an improvement in the adsorption of collagen-I compared to PPF baseline control. The results of this study show that 2D graphene nanomaterial reinforced porous PPF nanocomposites possess superior mechanical properties, cytocompatibility, and increased protein adsorption. The favorable cytocompatibility results opens avenues for in vivo safety and efficacy studies for bone tissue engineering applications.