Strong and bioactive gelatin–graphene oxide nanocomposites

Abstract

Bioactive gelatin-graphene oxide (GO) nanocomposites with varying GO contents were fabricated by a solution-casting method. With the addition of 1 wt% GO, the tensile strength, Young's modulus and energy at break of gelatin were found to increase by 84%, 65% and 158%, respectively. Such reinforcement effects were investigated in detail in terms of the size and morphology of GO sheets, the dispersion degree of GO sheets in gelatin matrix and the interactions between the two phases. The Young's moduli of the nanocomposites were well predicted by the Mori-Tanaka model with application of the effective volume fraction of reinforcement that takes into account the nanofiller and a fraction of the macromolecules adsorbed onto its surface. The GO nanosheets also improved the bioactivity of gelatin by inducing more calcium phosphate nanocrystals on the composites. GO acts as both an effective reinforcement filler and a biological activator in hydrophilic biopolymers such as gelatin, offering the biopolymer-GO nanocomposites great potential to be further developed in biomedical fields.

Graphene Oxide/Polymer‐Based Biomaterials

“…To improve gelatin's physical properties, up to 2 wt% GO was blended in with gelatin. Wan et al [3] prepared GO/gelatin nanocomposites via solution casting. With the addition of GO, the strength, modulus, and ductility simultaneously increased.…”

“…Therefore, it is used with reinforcement fillers or non-covalent/covalent crosslinking although residual crosslinking agents could lead to toxic side effects. [1,3] Gelatin loses its fibrous structure when it is exposed to a high degree of moisture. Therefore, a crosslinking agent is needed to improve its water stability.…”

“…[5,6] Studies so far have shown that GO generally upregulates the proliferation and differentiation of cultured secondary and stem cells. [3,7,8] However, a dosage above 50 μg ml À1 of GO was found to be cytotoxic. [9,10] Recently, the large-scale production of graphene-based materials has been achieved, which has facilitated their widespread use in many applications including biomedicine and the commercialization of these interesting materials.…”

“…A large aspect ratio, high strength, and high modulus of GO also contribute to the significant improvement of GO-reinforced polymers. [3] However, a good dispersion of GO in the polymer matrix is needed to achieve desirable physical and biological properties. [1] Natural polymers are biodegradable, non-toxic with low cost, good processability, and renewability as opposed to widely used synthetic polymers, which may release toxic by-products during their degradation.…”

“…It has a high surface area of upto 2630 m 2 g À1 , Young's modulus of 1 TPa, fracture toughness of 130 GPa, thermal conductivity of 5 MWK À1 , and relative conductivity of 720 k Sm À1 . [3,4] Graphene oxide (GO) which is a derivative of graphene is the oxidized form of graphene with hydroxyls, epoxides, diols, ketones, and carboxyls functional groups. The presence of oxygen on the edges and basal planes of GO increases its hydrophilicity and enhances its water dispersibility in comparison with graphene.…”