Spider silk reinforced by graphene or carbon nanotubes

Spider silk has promising mechanical properties, since it conjugates high strength (similar to 1.5 GPa) and toughness (similar to 150 J g(-1)). Here, we report the production of silk incorporating graphene and carbon nanotubes by spider spinning, after feeding spiders with the corresponding aqueous dispersions. We observe an increment of the mechanical properties with respect to pristine silk, up to a fracture strength similar to 5.4 GPa and a toughness modulus similar to 1570 J g(-1). This approach could be extended to other biological systems and lead to a new class of artificially modified biological, or 'bionic', materials.