Tiny electronic “tweezers” that can grab biomolecules floating in water with incredible efficiency have been developed using wonder material graphene.
The graphene tweezers developed at the University of Minnesota are vastly more effective at trapping particles compared to other techniques used in the past due to the fact that graphene is a single atom thick, less than 1 billionth of a meter. The research study was published today in Nature Communications.
The physical principle of tweezing or trapping nanometer-scale objects, known as dielectrophoresis, has been known for a long time and is typically practiced by using a pair of metal electrodes. From the viewpoint of grabbing molecules, however, metal electrodes are very blunt. They simply lack the “sharpness” to pick up and control nanometer-scale objects.
Using the University of Minnesota’s state-of-the-art nanofabrication facilities at the Minnesota Nano Center, electrical and computer engineering Professor Steven Koester’s team made the graphene tweezers by creating a sandwich structure where a thin insulating material call hafnium dioxide is sandwiched between a metal electrode on one side and graphene on the other. Hafnium dioxide is a material that is commonly used in today’s advanced microchips.
The team also showed that the graphene tweezers could be used for a wide range of physical and biological applications by trapping semiconductor nanocrystals, nanodiamond particles, and even DNA molecules. Normally this type of trapping would require high voltages, restricting it to a laboratory environment, but graphene tweezers can trap small DNA molecules at around 1 Volt, meaning that this could work on portable devices such as mobile phones.
Another exciting prospect for this technology that separates graphene tweezers from metal-based devices is that graphene can also “feel” the trapped biomolecules. In other words, the tweezers can be used as biosensors with exquisite sensitivity that can be displayed using simple electronic techniques.