Graphene-Amyloid Combo

Nanocomposites made of alternating layers of graphene and amyloid protein fibrils could improve graphene-based materials for biological applications, scientists at ETH Zurich report (Nat. Nanotechnol., DOI: 10.1038/nnano.2012.62). The fibrils stabilize graphene in water while preserving its two-dimensional carbon sheet organization, according to Raffaele Mezzenga and coworkers. The team made the nanocomposites by suspending graphene oxide in solution with different amounts of β-lactoglobulin and then reducing the graphene oxide to graphene. The nanocomposites’ conductivity decreased with increasing amyloid content, but even the least conductive hybrid was more conductive than pure graphene oxide films. By using vacuum filtration, the researchers obtained rigid, freestanding films sturdy enough to cut with scissors. The materials reversibly changed shape in response to changes in humidity, opening new possibilities for humidity sensors and moisture-activated switches, Mezzenga says. The team used the materials to make biosensors that measure enzyme activity.