Pitt team investigating molecular machination

Pitt researchers have received a $1 million grant to develop a new method for observing and… Pitt researchers have received a $1 million grant to develop a new method for observing and controlling individual molecules, a method which could revolutionize both the science of nanotechnology and the economic basis of today’s society.

Scientists in the field of nanotechnology have long sought the ability to construct synthetic molecular machines that resemble their naturally occurring counterparts.

But until very recently, these scientists couldn’t view the motion of single atoms and molecules and thus couldn’t hope to control their movement in specific ways.

Hrvoje Petek, a Pitt professor and principal investigator in this study, is passionate about viewing and controlling molecules and is determined to find a method that will greatly facilitate the growth of nanotechnology.

“Our goal is to learn how to excite and observe [molecular] motion with the ultimate goal of developing single molecule machines,” Petek said. “We know that such machines exist in biological systems. The ability to control the molecular motion would give us the means to develop molecular scale devices.”

The implications surrounding the development of such molecular devices are still largely speculative, but they have the potential to shift the control of molecular movement and synthesis from the nebulous hand of nature to the practical hands of humans.

“Molecules are the smallest entities of matter that we could conceivably consider to act as machines,” Petek said. “If we can learn how to control their motion for some practical application, we would reduce machines to their smallest possible scale.”

Current theory holds that if humans learn how to make and use these molecular machines, they could then conceivably construct synthetic molecular assemblers.

Molecular assemblers are found in the cells of all living organisms in the form of ribosomes, the organelles that catalyze the construction of protein.

If humans could one day make their own molecular assemblers, then they could make their own molecules independently of nature.

Conceivably, proteins and other manufactured products would no longer have to be obtained indirectly from nature but could be produced synthetically.

However, this future world is much too distant to contemplate with any seriousness, and for now Petek and his team of researchers are content to develop this new method for the sake of short-term scientific discovery.

“The common problem … is how to make molecules move in a deterministic way,” Petek said. “This is what we plan to study.”

Petek and his team will use complex, cutting-edge technology in the study.

“Such studies will be performed by combining scanning tunneling microscopy, which uses a sharp metal tip to interact with single molecules,” he said.

To trigger motion in the molecules, the researchers will use an ultra-fast laser that flashes once every 10 femtoseconds – a femtosecond is one billionth of one millionth of a second.

The single molecule will be “sandwiched” between a needle and a hard surface, exposed under the watchful eye of an extremely high-powered microscope and then shot with light from a laser to induce motion.

“Shining light onto such a molecular ‘sandwich’ will allow us to energize and observe molecular vibration,” Petek said.

He said that the $1 million grant will fund research positions as well as purchase the unique hardware needed to conduct the study.

“A large chunk of money will support the salary of excellent postdoctoral researchers, another chunk will go towards development of a unique laser that will operate at a very high pulse repetition rate, and another chunk will support Tamar Seideman, a professor at Northwestern University, and her group. She is an expert on the theory of molecular machines.”

According to Petek, several groups in Canada and the United States have been trying to develop imaging techniques for molecules and materials undergoing structural change, and he is proud that Pitt stands at the forefront of this scientific movement.

He is also thankful that Pitt and the W.M. Keck Foundation, the private body that gave the grant, are supporting scientific research in the face of serious obstacles.

“In times like now, when our government is decreasing investment in science and technology, it is extremely important to have support from private agencies. The support from the Keck Foundation will make it possible for us to undertake research that requires large investments, while most government agencies are struggling to keep the research enterprise from going into decline.”