Chad Mirkin / Northwestern University
Click for video: Nanoscale rods of gold can be coaxed to assemble themselves
into spheres, as seen in this photomicrograph. The gold nanospheres, developed
by Northwestern University's Chad Mirkin and his colleagues, are used in medical
testing devices. Click on the image to launch a video about Mirkin and his work.
What do tiny circuits, medical tests and a $500,000 prize have in common? They all fall into the domain of one of the world's foremost nanotech researchers. Last week, Northwestern University chemist Chad Mirkin received this year's $500,000 Lemelson-MIT Prize for "his revolutionary discoveries and sizable contributions" in the field of nanotechnology.
The prize is one of the richest rewards given to inventors, but by no means the only honor listed on Mirkin's Web page. The 45-year-old head of Northwestern's International Institute of Nanotechnology received the Feynman Prize in 2002, the Sackler Prize in 2003 and a long paragraph's worth of other awards.
|Chad Mirkin is the head of
International Institute of
Mirkin is the co-founder of two companies - NanoInk for lithography applications and Nanosphere for medical testing and treatment. He serves on President Obama's Council of Advisers for Science and Technology. He's the author of more than 380 manuscripts and more than 350 patent applications. He ranks No. 1 on the list of oft-cited nanoresearchers and No. 3 on the chemistry list.
Not everything that Mirkin touches immediately turns to gold nanoparticles: The companies he founded haven't generated huge profits just yet, and the nascent nanotech field is still facing questions about environmental and health effects.
But the technologies Mirkin pioneered are already being put to use: The diagnostic device that Nanosphere developed has been cleared by the Food and Drug Administration and might eventually be used to detect the early stages of Alzheimer's disease. NanoInk's molecular-scale printing technique is being used to make printed circuits, fight drug counterfeiters and further stem cell research.
Mirkin thinks the Lemelson-MIT Prize will give his work - as well as nanotechnology in general - a big boost. "It draws a lot of visibility to us, and I think it is going to facilitate the development of the next set of technologies," he told me by telephone Tuesday night (or Wednesday morning in Singapore, where he was lecturing at a conference on materials science).
Here's an edited transcript of my Q&A with Mirkin:
Cosmic Log: How is it that a guy like yourself can be involved with nanolithography as well as medical testing? Does that say something about the breadth of nanotechnology?
Mirkin: It says something about the core premise of nanotechnology, and that is that one can learn how to build on the nanometer length scale. You can begin to build materials that have properties that can be used in any application, ranging from nanolithography in the semiconductor industry to molecular electronics to molecular diagnostics and ultimately therapeutics. So, one of the core challenges in nanotechnology is learning how to build on this scale.
The tool that we adapted to nanolithography is one that allows you to do that. The medical diagnostics are based upon nanomaterials that we were studying for a very different purpose. We were trying to develop a fundamentally new way for building materials out of DNA, and we discovered that these materials had spectacular properties that made them very attractive for medical diagnostic purposes.
Much of what we do derives from the core ability to work with matter, much like Tinkertoys but on the nanometer length scale.
Q: Are the same tools involved in nanolithography as well as the diagnostic tool?
A: No, they're two core tools that we developed in the 1990s. One was this patterning method that uses a short tip probe to deliver molecules to a surface like a pen delivers ink to paper. That's the nanolithography. The other tool was a chemical tool that used DNA as a construction worker to assemble nanoparticles into higher-order structures. The basic idea was to tag particles of DNA, using the base-pairing schemes of DNA – the fact that A recognizes T, and G recognizes C – to build structures that literally assemble themselves into architectures that are preconceived. We can control the size and shape and the composition of the particles. The diagnostics derive from that capability.
Q: One of the things that I've noticed about nanotechnology is that it's sometimes hard to wrap your hands around it. I don't know if a lot of people understand exactly what nanotechnology represents as a separate technology. Do you find that to be the case?
A: Well, it's all relative. People seem to find it a lot easier to wrap their hands around nanotech than they do around the core disciplines like chemistry and physics. If I talk to somebody on a plane about my work in the context of chemistry, they'll often turn to me and cringe and say, "That was the worst class I had since I went to college!" If I talk to that same person in the context of nanotechnology, there's something about it that is very user-friendly. They're more interested, they ask more questions, they learn more about it. So I think it's the opposite. Nanotech has been a gift to science and laypeople. It bridges the gap.
Q: Why do you think that is? Is it because nanotechnology is about building things rather than trying to explain chemical reactions?
A: I think it's that, and I also think there's been the popularization of nanotech. They've seen it used in movies, in both a positive and negative light – and because of that connection with pop culture, there's a curiosity that makes the subject a little more approachable.
One of the appealing things is that you can make things small just for the sake of making them small, for miniaturized devices. But the really interesting thing about the science and the technology is that when you make things small, they become different. What we do with gold is a beautiful example. You know what bulk gold looks like, right? Well, you can miniaturize gold to the nanometer length scale to make these little particles. And at that scale, gold is red. In fact, in the Middle Ages they used gold particles as red dots in stained-glass windows.
If you change the shape of the gold on that scale, you can completely control the optical properties, you can make it any color in the spectrum you like. That's a neat concept: that one material can have completely different and tailorable properties when you can build it on the nanometer length scale. When you miniaturize things, they're different.
There's a lot of neat science there to figure out why that is, and to create the rules for explaining why it is. And there are a lot of neat applications for that architecture. We use it to create particles, and labels, and medical diagnostic systems. We tag the particles with DNA and proteins and use them to seek out markers for disease. We're creating highly sensitive and selective tools that have a chance to revolutionize the medical diagnostics industry, by making tests simple and affordable and capable of being used at the point of care.
Q: What does winning the Lemelson-MIT Prize mean for your work? How will this change the way you do what you do?
A: I don't know if it will change the way we're headed. Certainly it's incredible validation. This is not an ordinary prize. It's really one of the premier prizes, if not the premier prize, in invention. Being selected for this is an incredible honor. I'm humbled and blown away by the fact that some group of people thought that the work that we've done is important enough to be recognized by such an award. It draws a lot of visibility to us, and I think it is going to facilitate the development of the next set of technologies – which I think will ultimately lead to the commercialization and widespread use of nanotechnology in the field of therapeutics.
Q: That anticipated my question: What do you think is in store for nanotechnology in the future? Maybe you could tell me a little bit more about the therapeutic applications.
A: We're moving heavily in that direction. It turns out that nanomaterials can play a huge role in many areas of therapeutics. One example is HDL [high-density lipoprotein], the "good" kind of cholesterol. That's a nanostructure. We have statins that allow you to lower the levels of LDL [low-density lipoprotein, which is "bad" cholesterol]. To be healthy, what you really like is a good HDL-to-LDL ratio, so you'd like to learn how to raise HDL levels.
We've learned how to build nanostructures based on gold particles that mimic the properties of natural HDL, and we think that will lead to a whole new class of therapeutics that will be the complement to statins. If you think about what that can do for cardiovascular disease, the impact could be enormous. And it's not just cardiovascular disease. HDL is implicated in a lot of different diseases, as a positive thing to battle inflammation. Being able to raise effective HDL levels could be quite important. We're now testing particles that mimic the properties, the size and structure of HDL, and the ability to bind cholesterol and transport it. So we're really excited that this might lead to a whole new class of therapeutics designed to raise HDL levels and have an impact on cardiovascular disease as well as a wide range of diseases that involve inflammation.
Gene regulation is another promising technology for battling lots of diseases, including cancer, by being able to go into cells and correct genetic malfunctions. It turns out that we've got particles now that we've learned how to make, which are related to some of the particles we've used in diagnostics and are spectacular intracellular gene regulation tools. They can be designed to go into cells and turn switches that convert an unhealthy cell into a healthy cell, or cause cancer cells to selectively die.
We're finding a whole new suite of nanostructures that can lay the foundation for a new class of therapeutics. They could do intracellular gene regulation in a non-toxic, relatively low-cost manner. The implications there are enormous. You're talking about being able to cure or treat some of the most important diseases that are out there.
These materials are far from being actual therapeutics right now, but they're exceptional leads.
Q: It sounds as if folks who want to get into nanotechnology really have to be biochemists.
A: We have all sorts of different areas represented. I find biochemistry to be one of the more interesting areas, but the beautiful thing about nanotech is that it takes in all types of science, all types of engineering, all types of medicine.
People ask whether they should get trained specifically in nanotechnology, or should they get trained in chemistry or physics or biology or medicine first. I recommend the latter strategy. Get really smart in one core discipline, and then become smart in a lot of the nanotech approaches – rather than spreading yourself a mile wide and an inch deep.
Q: Is that the secret of your success?
A: Yeah, the reason I was successful is because I was a chemist by training. I learned how to do synthesis. I can make any reasonable molecule that I can draw on the board. That allows me, then, to make designer constructs that can be put on nanoparticles and nanostructures to give them the extraordinary functions that I've been describing. If you can't make those structures, then it doesn't matter what you write on the board.
Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about my upcoming book, "The Case for Pluto."