A nonenzymatic amperometric biosensor for sensitive detection of H2O2 has been successfully fabricated by using silver nanowires (AgNWs) supported on graphene nanosheets (GNs). The AgNWs were created through using a collagen-mediated biomimetic synthesis of silver nanoparticles on collagen nanofibers (Col-NFs). The electrode modified with the synthesized GN-AgNW nanohybrids displayed high electrocatalytic activity to the reduction of H2O2.