Dr. Alan Hunt
January 2001 - Sometimes, today’s scientific technology is surprisingly close to the seemingly far-fetched ideas of science fiction. Alan Hunt, Ph.D., an assistant professor of biomedical engineering and biophysics research at the University of Michigan, is refining a tool that has been likened to the “tractor beam” on Star Trek. The tool is called optical tweezers, and Hunt is using it to study cellular mechanics.
Cells depend on internal motors for locomotion, and these tiniest of motors are among the most efficient that exist, Hunt explained. So understanding how they work could lead to technological advances in nanotechnology by facilitating the production of instruments that work on a nanometer scale. These instruments would be sub-microscopic; one nanometer is approximately equal to 1/50,000 the width of an average human hair.
Not much is known about the mechanical characteristics of cells, which Hunt says is largely due to the lack of tools refined and precise enough to deal with the intricacies of cellular mechanics. So in order to pursue his research interests, Hunt is refining and developing two methods – optical tweezers and spatial knockout – to study cellular mechanics.
The optical tweezers are analogous to the tractor beams you see in Star Trek, Hunt said. The device uses a laser beam to form an “optical trap,” that allows one to grab and manipulate an object. Optical tweezers are based on two forces exerted by the laser: the scattering force and the gradient force. The scattering force pushes the object being manipulated by the tweezers away from the laser beam. At the same time, the gradient force, which is greater than the scattering force, pulls the object towards the beam, and thus the object is trapped by the laser.
Though the method of “trapping” objects is not new, Hunt is significantly refining the technology by adding additional traps. Coordinating multiple traps is a precise and delicate task, but it will allow Hunt to reach inside a cell and move around the organelles, the individual functional parts found inside the cell. The new trapping method will also make it possible for him to take quantitative measurements of the properties of cells, such as force, stiffness, and rigidity. “It will give me hard numbers to work with,” Hunt said.
A second new technology, spatial knockout, will also aid Hunt in his quest to understand the forces that control cellular mechanics. The spatial knockout uses high-energy pulsed lasers to eliminate specific parts of a cell.
The spatial knockout is a precise way to eliminate and destroy specific areas inside a cell. The technique will increase the precision of intracellular surgery by using high-energy pulses that damage a smaller area of the cell than previous methods, Hunt said.
“If a scientist is looking at something in a cell and wonders what the function of that thing is, he can knock it out and see what happens without it,” Hunt said. This will allow scientists to more accurately identify the function of different components within the cell. “Clip it and see what happens,” is how Hunt explains the general concept of spatial knockout.
He is simultaneously applying and refining both technologies using his BWF Career Award. The development of these two tools should improve the working knowledge of cellular mechanics, Hunt said, as well as provide valuable information on cellular function. “It will have a lasting fundamental impact by allowing scientists to study structures within cells with unprecedented precision,” he said. “I think [this technology] will permeate cell biology very quickly.”
Questions for Dr. Alan Hunt:
Name: Alan J. Hunt, Ph.D.
Recipient: BWF Career Award in Biomedical Sciences
Affiliation: Assistant Professor, Department of Biomedical
Assistant Research Scientist, Institute of
Assistant Professor, Biophysics Research Division
University of Michigan
How did you first discover you wanted to be a scientist?
I think I always knew I wanted to be a scientist. Much more difficult was deciding which discipline to pursue.
Why did you choose to enter your particular field of study?
I dabbled in a variety of fields as an undergraduate, and I worked for several years studying cellular immunology after I graduated. I found most of the work interesting, but nothing clicked until I began working in a biophysics lab studying the propagation of electrical signals in heart muscle. The quantitative and analytical approach to biological problems really appealed to me, and I applied to graduate school to study biophysics that year.
What has your BWF grant meant for your research?
Most directly, it has provided resources that have allowed my lab to hit the ground running. Rather than using established methodology to make incremental progress, we are progressing in leaps by pursuing exciting projects that require front-end development of new methodology and technology. Another less tangible, but equally important benefit is the recognition the award provides. In a sense, the award serves as a flag that alerts those who may not be familiar with your research to take a closer look. This has helped me establish my lab at an outstanding engineering college where I have access to technology and expertise that are not available in traditional cell biology environments.
What is the best thing about your job?
Thinking about science. It's extremely gratifying to develop new approaches or ways of looking at things that help us to understand nature and address the challenges of humanity.
What is your philosophy with respect to your research?
Always consider the dull explanation for results; it's probably the right one. I think it's too easy to get caught up in exciting interpretations that are inadequately demonstrated. As a corollary, when at all possible, results should be quantified; it strains objectivity when results are interpreted with generalities (e.g. "it's brighter" or "it rounds-up"). Numbers and statistics are vastly more useful and reliable.
What kind of advice would you give a scientist just entering academic research?
Try not to become too much of a specialist. There are many more opportunities for someone with a broad perspective.
What area of science is in most need of new researchers?
That's a tough one. Right now the market is very good for scientist studying single-molecule mechanics. In general, I think that scientists with strong quantitative analytical skills are best prepared to adapt to whatever field needs people.
If you had unlimited resources, what one big scientific question would you pursue?
The same as I am pursuing now, but faster.
What do you do for fun?
I like to hike, ski, and bike, but right now I mainly look after my two daughters.
What do you plan to do when you retire?
Take naps whenever I feel like it. Actually, I have no idea.
What is the best book you ever read?
Vanity Fair, by William Makepeace Thackeray.
-- This story was written by Megan Butler, Communications Intern