title: Graphene oxide/poly(acrylic acid)/gelatin nanocomposite hydrogel: experimental and numerical validation of hyperelastic model.
abstract: Owing to excellent thermal and mechanical properties, graphene-based nanomaterials have recently attracted intensive attention for a wide range of applications, including biosensors, bioseparation, drug release vehicle, and tissue engineering. In this study, the effects of graphene oxide nanosheet (GONS) content on the linear (tensile strength and strain) and nonlinear (hyperelastic coefficients) mechanical properties of poly(acrylic acid) (PAA)/gelatin (Gel) hydrogels are evaluated. The GONS with different content (0.1, 0.3, and 0.5 wt.%) is added into the prepared PAA/Gel hydrogels and composite hydrogels are subjected to a series of tensile and stress relaxation tests. Hyperelastic strain energy density functions (SEDFs) are calibrated using uniaxial experimental data. The potential ability of different hyperelastic constitutive equations (Neo-Hookean, Yeoh, and Mooney-Rivlin) to define the nonlinear mechanical behavior of hydrogels is verified by finite element (FE) simulations. The results show that the tensile strength (71%) and elongation at break (26%) of composite hydrogels are significantly increased by the addition of GONS (0.3 wt.%). The experimental data is well fitted with those predicted by the FE models. The Yeoh material model accurately defines the nonlinear behavior of hydrogels which can be used for further biomechanical simulations of hydrogels. This finding might have implications not only for the improvement of the mechanical properties of composite hydrogels but also for the fabrication of polymeric substrate materials suitable for tissue engineering applications.
authors.affiliation: Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161, Iran. Electronic address: sfaghihi@nigeb.ac.ir.
authors.forename: Shahab
authors.initials: S
authors.lastname: Faghihi
authors.affiliation: Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161, Iran; School of Mechanical Engineering, Iran University of Science and Technology, Tehran 16844, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Karimi
authors.affiliation: Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161, Iran.
authors.forename: Mahsa
authors.initials: M
authors.lastname: Jamadi
authors.affiliation: Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161, Iran; Biomedical Engineering Department, Amirkabir University of Technology, Tehran 15875, Iran.
authors.forename: Rana
authors.initials: R
authors.lastname: Imani
authors.affiliation: Biomedical Engineering Department, Maziar University, Noor, Royan 151, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Salarian
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D004548:Elasticity; D020342:Finite Element Analysis; D005780:Gelatin / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D008962:Models, Theoretical; D053761:Nanocomposites / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; D010087:Oxides; C006903:carbopol 940; D006108:Graphite; D005780:Gelatin
keywords: Constitutive equations; Finite element; Gelatin; Graphene oxide nanosheet; Poly(acrylic acid)