Spider silk famously has excellent mechanical properties, having both high strength (around 1.5 GPa) and toughness (around 150 J/g). Nicola Maria Pugno of the University of Trento and colleagues have now found a way to dramatically improve on these by feeding spiders aqueous dispersions of graphene or carbon nanotubes, which are then incorporated into their silk. Fracture strength went up to around 5.4 GPa and the toughness modulus to 1570 J/g. This is just a first step and opens the door to a new class of artificially modified biological material, says the team.