Graphene, a two-dimensional honeycomb sheet of carbon atoms, has been hotly scrutinized for its desirable electronic applications. Still, graphene has hardly been used as an atomically thin membrane. Graphene membranes are conformal to surfaces, entrapping liquids, gases, and nanoparticles. Here, we use centimeter sheets of grown graphene membranes on Cu to make graphene-biomolecule nanosandwiches. To that end, we cleanly layer graphene using a novel polymer support, poly(bisphenol A carbonate). We nanosandwich PC-transferred graphene sheets with tobacco mosaic viruses (TMV), NeutrAvidin (NA) proteins, and a complex of MBD1 protein attached to methylated DNA (MBD-DNA). The graphene layers act as atomic shrink wrap, protecting the biomolecules from environments like ultrahigh vacuum. Unusually, nanosandwiched proteins give bizarre hydration dynamics and denaturation characteristics. NA and MBD-DNA are ~5-6 nm in diameter and differ in their hydrophobic character. Nonetheless, these proteins "program" water, screening water away from the protein in a 10-fold larger radius. Nanosandwiched MBD-DNA do not change in shape when heated past the proteins' melting point. We explain our denaturation phenomena in these nanosandwiches with molecular dynamics simulations. Our results suggest that the graphene-biomolecule heterostructures are unique preservation cells, suited for assessing atomic-scale hydration. Moreover, we show preliminary work involving these nanosandwiches in atomistic studies like scanning tunneling microscopy.
Josh Wood is from a farm in western Illinois. After working many hard years on the farm, he left to earn his bachelor's degree from Valparaiso University in computer engineering. He received the degree with four minors in May 2008. During his undergraduate years, he investigated next-generation computing technologies like quantum-dot cellular automata, giving him an idea of what graduate school would be like. He was selected to be a NDSEG research fellow, which he used to pursue his Ph. D. at the University of Illinois in electrical and computer engineering. He is currently there, investigating the fabrication and characterization of carbon-based nanomaterials like graphene and carbon nanotubes. He is working with Dr. Joe Lyding and Dr. Eric Pop. (Source)
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Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL