Novel physically crosslinked graphene oxide (GO)-gelatin nanocomposite hydrogels were obtained by selfassembly. The hydrogels with various ratios of GO to gelatin were prepared, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy. The static and dynamic rheological properties of the hydrogels were investigated, along with the underlying hydrogel formation mechanisms. The storage modulus of the hydrogels (containing 98-98.5 wt % water) reached 114.5 kPa, owing to the relatively strong physical bonding (i.e., hydrogen bonding and electrostatic forces) between GO and gelatin. Drug release tests showed that the drug release from the hydrogel was pH-dependent, with 96% of the model drug released in a neutral environment, compared to 28% released in an acidic medium. These hydrogels could have potential in pH-sensitive drug delivery. V C 2014

Reduced graphene oxide–gelatin nanocomposite hydrogels show a relatively high storage modulus and biodegradability, having potential in drug delivery and soft tissue engineering.

Gelatin is an interesting biological macromolecule for biomedical applications. Here, double cross-linked gelatin nanocomposite hydrogels with incorporation of graphene oxide (GO) were synthesized in one pot using glutaraldehyde (GTA) and GTA-grafted GO as double chemical cross-linkers. The nanocomposite hydrogels, in contrast to the neat gelatin hydrogel, exhibited significant increases in mechanical properties by up to 288% in compressive strength, 195% in compressive modulus, 267% in compressive fracture energy and 160% shear storage modulus with the optimal GO concentration. Fourier transform infrared spectroscopy, scanning electron microscopy and swelling tests were implemented to characterize the nanocomposite hydrogels.

Graphene oxide (GO)-polyamidoamine (PAMAM) dendrimer nanocomposite hydrogels were prepared through one-step synthesis by mixing a GO suspension and a PAMAM solution at varying ratio of GO to PAMAM. The materials self-assembled into physically crosslinked networks, mainly driven by electrostatic interactions between the oppositely charged GO nanosheets and PAMAM dendrimer. The chemical structure of PAMAM dendrimer was studied by mass spectrometry, nuclear magnetic resonance spectroscopy and potentiometric titration.The structure and properties of GO-PAMAM nanocomposite hydrogels were investigated by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy and rheometry. The nanocomposite hydrogels exhibited a relatively high mechanical performance with a storage modulus of up to 284 kPa, as well as self-healing property, owing to their reversible and multiple physical cross-links. These hydrogels may be further developed for biomedical applications.2

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