Graphene Oxide—A Tool for the Preparation of Chemically Crosslinking Free Alginate–Chitosan–Collagen Scaffolds for Bone Tissue Engineering (original) (raw)

2018, ACS Applied Materials & Interfaces

Developing a biodegradable scaffold remains a major challenge in bone tissue engineering. This study was aimed at developing novel alginate-chitosan-collagen (SA-CS-Col) based composite scaffolds consisting of graphene oxide (GO) to enrich porous structures, elicited by freeze-drying technique. To characterize porosity, water absorption and compressive modulus, GO scaffolds (SA-CS-Col-GO) were prepared with and without Ca 2+-mediated crosslinking (chemical crosslinking) and analyzed using Raman, FTIR, XRD, and SEM techniques. Incorporation of GO into SA-CS-Col matrix increased both crosslinking density as indicated by the reduction of crystalline peaks in the XRD patterns and polyelectrolyte ion complex as confirmed by the FTIR. Graphene oxide scaffolds showed increased mechanical properties which were further increased for chemically crosslinked scaffolds. All scaffolds bared interconnected pores of 10 µm to 250 µm range. By increasing the crosslinking density with Ca 2+ , a decrease in porosity/swelling ratio was observed. Moreover, SA-CS-Col-GO scaffold with or without chemical crosslinking was more stable as compared to SA-CS or SA-CS-Col scaffolds when placed in aqueous solution. To perform in vitro biochemical studies, mouse osteoblast cells were grown on various scaffolds and evaluated for cell proliferation by using MTT assay, and mineralization and differentiation by alizarin red S staining. These measurements showed a significant increase for cells attached to the SA-CS-Col-GO scaffold, compared to SA-CS or SA-CS-Col composites. However, chemical crosslinking of SA-CS-Col-GO showed no effect on the osteogenic ability of osteoblasts. These studies indicate the potential use of GO to prepare free SA-CS-Col scaffolds with preserved porous structure with elongated collagen fibrils, and that these composites, which are biocompatible and stable in a biological medium, could be used for application in engineering bone tissue.