Graphene oxide-enriched double network hydrogel with tunable physico-mechanical properties and performance

An emerging approach to obtain polymeric hydrogels with superior properties is integrating carbon-based nanomaterials within their network structure. On the other hand, hydrogels with tailored physical and mechanical characteristics are desirable class of materials which have extensive application in drug delivery and tissue engineering. This study presents a strategy to achieve graphene oxide (GO)-enriched hydrogels with modulated physico-mechanical properties and performance. GO/poly acrylic acid (PAA)/gelatin hydrogels are fabricated via in situ polymerization method followed by chemical crosslinking of gelatin molecules. N,N'-Methylenebisacrylamide (BIS) in a various concentrations is used within the prepolymer composition as cross linking agent to prepare a set of nanocomposite hydrogels. Fourier transform infrared (FTIR), X-ray diffraction (XRD), and atomic force microscopy (AFM) are utilized to characterize the fabricated hydrogel samples. The microstructure of samples is analyzed with scanning electron microscopy (SEM). The mechanical properties of the specimens are evaluated by rheometry. The swelling behavior, degradation kinetic and porosity of the hydrogels as well as their in vitro cytotoxicity are also assessed. The results show successful synthesis of nano GO sheets and polymer composites. The increase of cross-linker concentration is decreased-the swelling ratio and increased the porosity of hydrogel samples. A wide range of pore diameters (70-300 pm) and mechanical stiffness (storage modulus of 2000-25,000 Pa) is obtained. Through manipulation of cross-linking density the degradation rate of nanocomposite hydrogels is controlled. Finally, no toxicity is detected by exposure of the hydrogel extracts to osteoblast osteosarcoma cells. The optimized hydrogel samples having appropriate range of physical characteristics and functionality suggest the application of the 3D structures as scaffold material for hard tissue construction. (C) 2016 Elsevier B.V. All rights reserved.