Spider silk reinforced by graphene or carbon nanotubes

Spider silk has promising mechanical properties, since it conjugates high strength (~1.5 GPa) and toughness (~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 ~5.4 GPa and a toughness modulus ~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.