- How did you become interested in nanotechnology? Did you have an epiphany or did your interest gradually grow?
"I read a lot of science fiction growing up (and still do, when I have the time). The word 'nanotechnology' started appearing in some of the stories I read when I was in high school. To check out what this was about, I picked up K. Eric Drexler's book Engines of Creation. You don't often find a science book that can be classified as a real page-turner, but this one was. His description of molecular machinery was fascinating from an engineering point of view, but the best part of the book started when he began describing the impact these nanomachines would have on our lives. The argument that sold me on the feasibility of nanotechnology was simply that we have examples of working nanomachines within us. Biological life is possible only through the use of molecular machines. Nanoscale rotors store power in adenosine triphosphate, a simple chemical, by tapping the energy of a stream of flowing ions. Nanoscale ratchets let our muscles move and help move items within a cell. The list goes on and on.
"I made sure to pick up as much nanotechnology-related literature as I could after that. There are plenty of predictions and science fiction stories about what nanotechnology could do for us, many of them involving complete transformations of the world around us, but unfortunately I've found that there isn't a detailed roadmap for how we are to get from here to there. Some think that chemistry is the place to start; others think that top-down manufacturing processes like those used in microelectronics fabrication are the way to go to achieve the promise of nanotechnology. It appeared to me that both paths will meet at some point. Thus, I developed an interest in chemistry as well as engineering."
- What do you plan to do when you finish your degree?
"I plan to go on to work in industrial research and development. I'm an engineer at heart, so I'm more interested in technology than science. While I believe that the basic science work done at universities and government research labs is extremely valuable, I like to see actual products reaching the market that improve people's daily lives.
Recently, I have taken an interest in technology transfer from academia to the private sector. Here at the UW you're surrounded by great ideas. Many of them could have significant impact on the world if commercialized in some form, but it takes an entrepreneurial spirit and a lot of work to do so. At some point, I would like to take part in the introduction of a new technology to market."
- What advice would you give to someone (a college or high school student) who is interested in pursuing nanotechnology research?
"I would advise a broad scientific course of study. I chose to study chemical engineering as an undergraduate because it is a very inclusive major, taking in elements of chemistry, physics, and engineering. I would also highly recommend courses in biochemistry and general biology, because it is my belief that we can learn much from the molecular machinery within all living things. I believe that the line between biology and technology will become blurred (we can even see some of this today) as we engineer biological systems to perform complex tasks and build nanomachines to interact with living organisms.
"Even though this might be obvious, you can't go wrong with a solid computer science background. In addition to the day-to-day advantages of being technologically literate, a researcher comfortable with the ins-and-outs of information technology is at a significant advantage. From simple analysis of experimental results to molecular modeling simulations of nanomachines, computers are invaluable research tools and will become ever more important as the complexity of the systems being studied increases.
"Finally, I would say just read as much as you can get your hands on. If you haven't already, check out K. Eric Drexler's The Engines of Creation as a good introduction to the potential of nanotechnology as well as his "Nanosystems", which is written as a textbook for a class on nanotechnology. There are too many others to name, but try reading those two. Science fiction novels are also great, because they provide a venue for some very bright individuals to think out loud about the possibilities of new technologies. My personal favorites are novels by Greg Bear and Peter Hamilton, but again there are plenty of others to choose from."
- http://www.warf.ws/news/newsletters-article.jsp?articleid=97
- - a press release about the microplotter
- http://www.mrsec.wisc.edu/Edetc/nanolabAgthiol/
- - an on-line lab activity about liquid-surface interactions.
- B.J. Larson, S.D. Gillmor, and M.G. Lagally, "Controlled Deposition of Picoliter Amounts of Fluid Using an Ultrasonically Driven Micropipette,"Review of Scientific Instruments, in review.
- - This is an accessible article about the microplotter and its capabilities.
Brad Larson: Turning LEGOs into Nanotechnology Gold
Greta M. Zenner
Brad Larson knows it pays to be a nanotechnologist and tinker with LEGOs. When he and a University of Wisconsin-Madison (UW) Business School graduate student, Vivek Dubey, entered a business plan competition, they won second place and $7,000. The innovative pair developed a business proposal for a device that Brad created. The machine, called a fluid microplotter, is the first of its kind, and it has plenty of potential applications in both science and business, as is evident from judges' decision.
Brad shows off the small size of the microplotter's work. |
Brad began developing the microplotter under the supervision of Professor Max Lagally when he joined the Materials Science Program at the UW two years ago. The device uses sounds that humans can't hear, called ultrasonic vibrations, to put tiny drops of liquid onto a surface. The microplotter can currently deposit dots of liquid down to one micrometer in diameter, but Brad hopes to reach sizes smaller than that in the future. You can't hear the sound that deposits the liquid, and soon you won't even be able to see the resulting spots. The inspiration behind the microplotter lies in an instrument developed by Brad's colleagues to deposit DNA onto a surface. The original device, however, was far from achieving its goal; it could only spray liquid uncontrollably. With the permission of his fellow researchers, Brad worked with their machine to increase its control and precision. |
Turning the liquid-spraying tool into a prize-winning device, however, wasn't an overnight accomplishment. "It took three months of tinkering to get the first prototype," says Brad. "The microplotter is a totally different device than what I started with, but it was done through gradual changes. This machine has been operational since October 2002, and it's the big brother of the original, smaller machine." Brad built the fluid microplotter and everything related to it himself, so his undergraduate training in chemical engineering and computer science has come in handy. Creativity, though, has been just as important as formal education. He fashioned his invention out of LEGOs, random scrap parts, and zip ties, and he even did the wiring himself. "Just don't touch the wires when the machine is on!" warns the resourceful grad student with a smile, recognizing the limitations of his make-do approach. |
The microplotter |
Brad demonstrates the software he wrote. |
Brad also wrote the computer program that controls the machine with its tiny glass needle, which deposits the nearly invisible dots of liquid onto a range of surfaces, including silicon, plastics, and glass. "You can't just go buy the software at Best Buy or Target," he explains. |
The microplotter uses tiny glass needles like the ones used for embryo injections. Because the needles are so small, getting liquids into them is easy, says Brad. "I simply dip them in a supply well." At this tiny scale, a force called capillary action draws the liquid up inside the needle. Capillary action happens because the liquid molecules are attracted to the needle and to each other. You can see it at work by dipping a paper towel into a glass of water and watching the water creep up the paper towel. Getting the liquid out of the needle takes a little more work. Attached to the needle is a piezoelectric, which expands and contracts with different currents. The piezoelectric pumps liquid at varying forces, depending on the frequency of the current. The higher the current, the more liquid pumped out of the needle and the larger the amount of liquid deposited and onto the surface. |
The microplotter needle on the viewing screen |
The microplotter can regularly deposit volumes of liquid less than one picoliter. (A picoliter is one trillionth of a liter - 10 -12 , as compared to a nanoliter, which is one billionth - 10 -9 .) Depositing small amounts of liquid, however, isn't without its difficulties. "The greatest challenge," says Brad, "is being able to control the volume you're putting down. When you're talking about picoliters and femtoliters (10 -15 liter), the degree of control you need is far beyond that needed for microliters or even nanoliters."
Brad also has to consider other issues when working on the pico- and nanoscale. Because he uses such small volumes, some fluids evaporate before he can even deposit them. "A picoliter spot of water evaporates almost instantly. A one microliter spot you put down by hand can take an hour to evaporate." In addition, the interaction between the liquid and surface it's being pumped onto affects the size of the dot. Some liquids and surfaces "like" each other more, so the liquid spreads out and forms a larger spot. The opposite is true when they repel each other.
Given these challenges of the nano- and picoscale, there are still questions surrounding how the machine functions, even though Brad invented and built the microplotter and can make it work. "We don't really understand the physics behind the depositing of the liquid," he says.
This doesn't seem to faze Brad and others interested in the possible applications of the microplotter. Brad would like to work on several patent processes for a variety of different uses for the machine. It's important to him that his inventions don't stay in the lab.
Supporting him in this endeavor are the Wisconsin Alumni Research Fund (WARF) and the UW's Office of University-Industry Relations (UIR) . UIR backs Brad financially and WARF helps with the patent process. "I really like working with WARF," states Brad. "They really want to get technology out of the lab and into the public, a philosophy I strongly agree with. I like to see actual products reaching the market that improve people's daily lives."
Brad describes many possible real-life applications for his microplotter, ranging from growing carbon nanotubes to improving DNA microarrays to helping create nanoscale electronics. But there is one he finds the most exciting - TVs you roll up. "I think the greatest potential application of this device lies in making low-cost, flexible microelectronics. Think of a TV you could unroll onto a wall or a newspaper that could change headlines during the day as news broke."
Brad's UW colleagues have additional plans for the microplotter, including some nano applications, but it's too early to talk about them, he says, because they're still in the early research phases.
The future holds promise for the ingenious grad student and his microplotter. Having already won a prize, applied for several patents, and intrigued many scientists and businesses, Brad is excited about the possibilities, even if he's not sure about the next steps. One thing he does know, however, is that even though playing with LEGOs paid off in the past, his education will bring him even greater satisfaction and rewards in the future. "We'll commercialize sometime, but just not right now. I still need to finish my Ph.D.!"
An interview with Brad
Copyright © 2004 The Board of Regents of the University of Wisconsin System.
This page created by Greta Zenner. Last modified May 4, 2005.