  Here, we report the production of silk incorporating graphene and carbon
nanotubes directly by spider spinning, after spraying spiders with the
corresponding aqueous dispersions. We observe a significant increment of the
mechanical properties with respect to the pristine silk, in terms of fracture
strength, Young's and toughness moduli. We measure a fracture strength up to
5.4 GPa, a Young's modulus up to 47.8 GPa and a toughness modulus up to 2.1
GPa, or 1567 J/g, which, to the best of our knowledge, is the highest reported
to date, even when compared to the current toughest knotted fibres. This
approach could be extended to other animals and plants and could lead to a new
class of bionic materials for ultimate applications.
