The World's Tiniest Tweezers

From Minnesota Alumni Magazine Spring 2018

By Elizabeth Foy Larsen

If you thought tweezers were for removing slivers, researchers from the U’s College of Science and Engineering have news for you. Using graphene—a material made of a single layer of carbon atoms that is considered the strongest substance ever tested—they have developed tiny electronic pincers that can grab biomolecules floating in water.

Using the U of M’s nanofabrication facilities at the Minnesota Nano Center, electrical and computer engineering professor Steven Koester and his team created these tweezers by fashioning a kind of “sandwich,” where a thin insulating material called hafnium dioxide (used in microchips) is placed between a metal electrode and graphene.

Trapping nanometer-scale objects is not new. Called dielectrophoresis, the procedure has typically been practiced by using a pair of metal electrodes for tweezers. Unfortunately, those electrodes often lack the “sharpness” to pick up and control nanometer-scale objects.

Graphene’s thinness makes the tweezers more precise. “To build efficient electronic tweezers to grab biomolecules, basically we need to create miniaturized lightning rods and concentrate a huge amount of electrical flux on the sharp tip,” explained Sang-Hyun Oh, a professor in the Department of Electrical and Computer Engineering. Among its many attributes, graphene also conducts electricity very efficiently.

Researchers hope that one day this capability will lead to the development of handheld biosensors operated by smart phones, which doctors could use to diagnose patients in hospitals, ambulances, doctors’ offices, or even a patient’s home.

This research was published in November in Nature Communications.

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