3D printed hetero-layered composite scaffold with engineered superficial zone promotes osteogenic differentiation of pre-osteoblast MC3T3-E1 cells

In bone tissue engineering, a new design of composite scaffold with various compositions by incorporating both natural and synthetic cues via dual nozzle 3D printing technique could efficiently accelerate the cell differentiation to osteogenic lineage. Based on the hypothesis that a biomimetic scaffold per se can supply the vital cues to provoke bone formation, 3D printed poly(ε-caprolactone) (PCL) scaffold loaded with synthetic hydroxyapatite (HAs) decorated on graphene oxide (GO) sheets (GO@HAs), was developed. To further improve its osteogenic potential, the upper and lower layer/s of scaffolds were 3D printed using another ink containing PCL and naturally allograft HA (HAa). The FE-SEM images of the 3D printed scaffolds revealed a highly regular architecture, demonstrating the successful printability of the developed materials. The compressive mechanical test confirmed the drastic role of GO@HAs on the enhancement of Young's modulus and mechanical strength of the PCL scaffold. Moreover, existence of HAa on the upper and lower sections of scaffold interestingly improved the cellular behavior of the 3D printed scaffold without having an adverse effect on mechanical features. The experimental results indicated that such engineered scaffold significantly facilitated the cell attachment and evoked higher levels of pre-osteoblast MC3T3-E1 differentiation than PCL/GO@HAs scaffold as demonstrated by alizarin red staining, ALP activity and osteo-related gene expression. Taken together, these results indicate that such fascinating scaffold comprising both mechanical and biological cues has a high potency for inducing bone repair and also open new avenues for future advancements in the realm of bone tissue engineering exploration. [Display omitted]