Lieber Develops 'Nanotweezers' to Manipulate Molecules

The invention has been touted in Science magazine and lauded on National Public Radio (NPR). It's not the latest software innovation, not the next generation cell phone, but tweezers. The familiar tool has been modified in an innovative way to aid the study of microscopic objects.

The "nanotweezers" are thousands of times smaller than the conventional eyebrow-pulling tweezers. Hyman Professor of Chemistry Charles M. Lieber developed them to manipulate and study objects as small as several atoms.

Lieber and Philip Kim, who was a doctoral student in chemistry last year, published the results last week in Science.

"We started making just one toolkit that will help others develop real nano-technologies," Kim said. "This is just a first step."

Nanotechnology involves building miniature tools from individual molecular structures that can manipulate other small molecules.

The nanotweezers have two carbon tubes that can grasp molecules.

In an NPR interview last week, Lieber compared nanotweezers to human-sized pliers.

"If you were trying to build something with a hammer and nails or screws and things, you could use a screwdriver or something to push nails around on the piece of wood," Lieber said. "But if you didn't have a pliers to lift them up...you couldn't actually hammer the nail in."

Also, because an electrical current is passed between two electrical contacts on the tweezers and through the object, the object's electrical properties can be investigated with the tweezers.

Molecular structures like the tweezers also have important technological implications.

"There is a lot of miniaturization going on in all fields, including electrical and mechanical circuitry. These tools will directly affect those developments," said Assistant Professor of Chemistry and Chemical Biology Hongkun Park.

Park studies the physical chemistry of nanoscale structures.

"There is so much potential in the field of nanotechnology. But in order to realize the potential you need to have the tools," he said.

Lieber said on NPR that the uses of nanoscale tweezers might even extend to surgery or subcellular manipulation.

Kim also stressed the importance of tools like the tweezers for all areas of scientific research.

Kim said the project was inspired by a conference three years ago, but he and Leiber did not begin to work together until last year.

The tweezers consist of two carbon nanotubes connected to electrodes on nanometer-sized glass tubes. Voltages applied to the electrode open and close the tweezers, allowing them to pick up and drop molecules.

According to the Science paper, carbon nanotubes are suitable for building blocks of the tweezers because they continue to be tough and to conduct electricity at very small sizes.

Scanning probe microscopes, which can also be used to manipulate molecules, are inferior to nanotweezers because they only have a single probe that can move the molecules.

Much of Lieber's other research focuses on nanoscale projects like this. He could not be reached for comment yesterday.

Kim is now a post-doctoral student in chemistry at the University of California, Berkeley. He is working to extend these nanotechnologies to build electrical and mechanical devices that will manipulate molecules.