Machine Design

Nanotubes: The Cutting Edge

Researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder (CU) designed a carbon nanotube knife that could become a tabletop tool for biologists, letting them slice and dice cells more precisely.

Julie Kalista
Online Editor

Scanning electron micrograph of a prototype 'nanoknife' shows a single carbon nanotube stretched between two tungsten needles. Triangular probe is the tip of an atomic force cantilever used to determine the breaking point of the knife. (Color added for clarity.)
Scientists also might use the nanoknife to make 3D images of cells and tissues for electron tomography, a process that requires samples less than 300 nanometers thick.

To build the nanoknife, scientists welded a carbon nanotube between two electrochemically sharpened tungsten needles so the knife resembles a steel wire used to cut blocks of cheese.

NIST researchers assessed the knife's mechanical strength in force tests, applying increasing pressure to the device. The team found that the welds were the weakest point of the nanoknife and they are now experimenting with alternative welding techniques. Researchers plan to test the nanoknife on a block of wax later this year.

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