University of Illinois team finds that defects in graphene membranes may improve biomolecule transport

Researchers at the University of Illinois examined how tiny defects in graphene membranes, formed during fabrication, could be used to improve molecule transport. They found that the defects make a big difference in how molecules move along a membrane surface. Instead of trying to fix these flaws, the team set out to use them to help direct molecules into the membrane pores.

Nanopore membranes have generated interest in biomedical research because they help researchers investigate individual molecules - atom by atom - by pulling them through pores for physical and chemical characterization. This technology could ultimately lead to devices that can quickly sequence DNA, RNA or proteins.

MIT team uses wax to smooth out wrinkles in graphene

Researchers at MIT have utilized an everyday material - wax- to protect graphene from performance-impairing wrinkles and contaminants. Removing graphene from the substrate it’s grown on and transferring it to a new substrate is known t be challenging. Traditional methods encase the graphene in a polymer that protects against breakage but also introduces defects and particles onto graphene’s surface. These interrupt electrical flow and stifle performance.

MIT process for smoothing out graphene wrinkles with wax imagea Schematics showing the process of paraffin-assisted graphene transfer. b Schematics showing the effect of paraffin’s thermal expansion on graphene wrinkle. c A typical paraffin-supported graphene film floated on water at different temperatures

The MIT team describes a fabrication technique that applies a wax coating to a graphene sheet and heats it up. Heat causes the wax to expand, which smooths out the graphene to reduce wrinkles. Moreover, the coating can be washed away without leaving behind much residue.

Researchers catalog graphene defects

Researchers at MIT have produced a catalog of the exact sizes and shapes of defects and holes that would most likely be observed (as opposed to the many more that are theoretically possible) when a given number of atoms is removed from the atomic lattice. The MIT team collaborated on this project with researchers at Lockheed Martin Space and Oxford University.

MIT develops graphene defects catalog imageThe 12 different forms that six-atom vacancy defects in graphene can have, as determined by the researchers

“It’s been a longstanding problem in the graphene field, what we call the isomer cataloging problem for nanopores,” Michael Strano from MIT says. "For those who want to use graphene or similar two-dimensional, sheet-like materials for applications including chemical separation or filtration", he says, “we just need to understand the kinds of atomic defects that can occur,” compared to the vastly larger number that are never seen".

NYU team's findings on defects in graphene to benefit environmental and medical sensors

A team of NYU researchers has tackled the longstanding question of how to build ultra-sensitive, ultra-small electrochemical sensors with homogeneous and predictable properties, by discovering how to engineer graphene structure on an atomic level. The team's findings could benefit biochemical detection, environmental monitoring, and lab-on-a-chip applications

Finely tuned electrochemical sensors (also referred to as electrodes) that are as small as biological cells have tremendous potential for medical diagnostics and environmental monitoring systems. However, efforts to develop them have encountered obstacles, like the lack of quantitative principles to guide the precise engineering of the electrode sensitivity to biochemical molecules.

Team at Australia's RMIT finds silicon contamination of graphene as a hindrance to commercial adoption

Researchers at Royal Melbourne Institute of Technology (RMIT) have found that graphene could better fulfill its potential when purified to remove silicon, doubling its electrical performance.

Despite researchers demonstrating countless possible applications of graphene, many people feel that graphene is thus far showing rather sluggish industrial adoption. Now, researchers based at RMIT have proposed a possible reason for this and suggested how graphene's full potential could be unlocked.