Growth of metal-metal oxide nanostructures on freestanding graphene paper for flexible biosensors

Flexible biosensors are of considerable current interest for the development of portable point-of-care medical products, minimally invasive implantable devices, and compact diagnostic platforms. A new type of flexible electrochemical sensor fabricated by depositing high-density Pt nanoparticles on freestanding reduced graphene oxide paper (rGOP) carrying MnO ₂ nanowire networks is reported. The triple-component design offers new possibilities to integrate the mechanical and electrical properties of rGOP, the large surface area of MnO ₂ networks, and the catalytic activity of well-dispersed and small-sized Pt nanoparticles prepared via ultrasonic-electrodeposition. The sensitivity and selectivity that the flexible electrode demonstrates for nonenzymatic detection of H ₂O ₂ enables its use for monitoring H ₂O ₂ secretion by live cells. The strategy of structurally integrating metal, metal oxide, and graphene paper will provide new insight into the design of flexible electrodes for a wide range of applications in biosensing, bioelectronics, and lab-on-a-chip devices.