Biocompatible double network poly(acrylamide-co-acrylic acid)–Al3+/poly(vinyl alcohol)/graphene oxide nanocomposite hydrogels with excellent mechanical properties, self-recovery and self-healing ability

Abstract

In this study, we have fabricated poly(acrylamide-co-acrylic acid)–Al³⁺/poly(vinyl alcohol)/graphene oxide (PAmAA–Al³⁺/PVA/GO) double network nanocomposite hydrogels by free-radical polymerization and a freeze–thaw cycle in the presence of graphene oxide and aluminum ions. The pH-sensitivity, surface morphology and mechanical properties can be tuned by adjusting the contents of GO, PVA and Al³⁺. The resulting hydrogels exhibit significant pH-sensitivity and an interconnected pore channel. The PAmAA–Al³⁺/PVA/GO hydrogels also exhibit high tensile strength, a large elongation at break and high toughness, which is due to the introduction of GO and formation of dynamic reversible bonds. These dynamic reversible bonds formed in the synthesized double network nanocomposite hydrogels could efficiently dissipate energy and recover the three-dimensional network. The combination of nanoparticles, dynamical reversible bonds and the double network structure significantly improves the physicochemical properties of these hydrogels. Finally, subcutaneous implantation of the synthesized nanocomposite hydrogels in mice showed no local inflammatory response, indicating good biocompatibility in vivo. In conclusion, PAmAA–Al³⁺/PVA/GO double network nanocomposite hydrogels with tunable three-dimensional network structures, mechanical properties, good pH-sensitivity, self-healing ability and biocompatibility are promising biomaterials for tissue engineering.