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Posted: Jan 12, 2011
Scaling up: The future of nanoscience
(Nanowerk News) In the late 1950s, Richard Feynman famously imagined a science where researchers and engineers could achieve remarkable feats by manipulating matter and creating structures all the way down to the level of individual atoms.
Now, 51 years after Feyman proposed "There's Plenty of Room at the Bottom" for science to discover, researchers in nanoscience and nanotechnology are gathering to imagine how this young field may change in the next half a century– and in the process, also change our world. They will be joined by scientists in other fields whose work is already being transformed by nanoscience. Together, they will focus on the great opportunities that lie in scaling up from atomic assembly and individual nanodevices to macroscopic systems and structures with emergent properties and functionality.
Clockwise from top: David Awschalom, Angela Belcher, Michael Roukes and Don Eigler, four participants and moderators for the next Kavli Futures Symposium. Credit: Caltech and Scanpix (Eigler)Clockwise from top left: David Awschalom, Angela Belcher, Michael Roukes and Don Eigler, four participants and moderators for the next Kavli Futures SymposiumThe event is the next Kavli Futures Symposium, to be held at the California Institute of Technology on January 15, 2011. For the Symposium, an assembly of pioneering scientists will gather to focus on four key topics in nanoscience: atomic-scale assembly and imaging, mesoscopic quantum coherence, the "nano/bio nexus" and nanotechnology frontiers. Co-chairing the symposium are Michael Roukes, co-director of the Kavli Institute of Nanoscience at the California Institute of Technology, and IBM scientist Donald Eigler.
Three of those nanoscientists -- Eigler, MIT materials scientist Angela Belcher and UC Santa Barbara physicist David Awschalom -- joined in a recent teleconference to discuss the upcoming symposium and Feynman's legacy. Roukes provided additional responses in a subsequent interview. Each of these four is playing a key role in the symposium as co-moderators of sessions on topics where they are recognized scientific leaders.
When Richard Feynman gave his now-famous talk "There's Plenty of Room at the Bottom," he outlined with amazing clarity future wonders of nanoscale science and technology. The co-chairs of the "Plenty of Room in the Middle" symposium reflect on the celebrated physicist's role in the narrative of nanoscience.
Donald Eigler is renowned for his breakthrough work in the precise manipulation of matter at the atomic level – including the 1989 achievement of spelling "IBM" with xenon atoms. Co-moderator of the Symposium's session on "Atomic-scale Assembly and Imaging," among his many honors is the 2010 Kavli Prize in Nanoscience.
David Awschalom, a professor of physics, electrical, and computer engineering at the University of California, Santa Barbara, is co-moderator of the Symposium session "Mesoscopic Quantum Coherence." He is a pioneer in the field of semiconductor spintronics, exploring the quantum mechanical behavior of charges and spins in nanostructures and the foundations of solid-state quantum information processing.
Michael Roukes, co-moderator of the Symposium session on "The Nano/Bio Nexus," is a professor of physics, applied physics and bioengineering at Caltech and co-director of the Kavli Institute of Nanoscience. He founded the field of nanoelectromechanical systems (NEMS) in the early 1990s, and since then he has published broadly on nanoscience, lectured at most major research centers worldwide, and is active on many national and international committees promoting these fields.
Angela Belcher, co-moderator of "Nanotechnology Frontiers," is the W. M. Keck Professor of Energy, Materials Science & Engineering and Biological Engineering at the Massachusetts Institute of Technology. She is widely known for her work on evolving new materials for energy, electronics and the environment. Belcher has founded two start-ups and has received numerous national awards, including a MacArthur Foundation Fellowship and a Four Star General Recognition Award from the U.S. Army.
Device to measure the quantum unit of thermoelectricity. (Credit: Michael Roukes)Roundtable Teleconference
The Kavli Foundation (TKF): The Symposium is called – "Plenty of Room in the Middle" – which of course is a play on the title of Richard Feynman's famous lecture. What does this title imply to you about the challenges or opportunities facing nanoscience going forward?
Donald Eigler: Feynman's idea about how to get to doing things on a small scale was to create generation after generation of small machines making ever smaller machines. He imagined that, if we were skillful and lucky, this might even continue until we hit the smallest scale – building things by putting the atoms where we want – Feynman's "bottom," if you will. Well that's not the way it happened. In 1989, we leap-frogged Feynman's "generation-after-generation" and plunged directly to his "bottom." We learned to "…arrange the atoms the way we want; the very atoms, all the way down!" [a quote from Plenty of Room] The challenge that lies before us is to master the mesoscale structures that are much larger than a single atom, that exhibit unique properties, and that at times might be fully quantum mechanical in their behavior. This is the "middle."
TKF: Angela and David, in your sense, what's in the "middle" that's important?
David Awschalom: I think that one of the interesting things about having atomic and near-atomic scale flexibility now in constructing systems is that it brings quantum physics from an academic discipline to a future framework for potentially disruptive technologies. There's a great deal of interest and a lot of excitement in trying to manipulate small groups of atoms to build quantum mechanical systems that have truly novel functionality – very different and very distinct from what we think about or see around us today. And in that sense I think [the symposium] is a magnet for bringing together very different disciplines, from engineers to scientists, to think creatively about how we might explore this opportunity in a very novel way.
Angela Belcher: I agree with the last comments for sure. I think that the exciting area is bringing together the different approaches from the different disciplines, and seeing how, when you manipulate atoms and materials on this length scale, what can happen. And I think that a next big area is bringing it to scale, bringing it to devices that can affect our everyday lives.
Comment by Michael Roukes: I picked this symposium's title because of the reasons the others have conveyed pretty clearly, which is that we've made incredible advances in nanoscience over the past 20 years or so. We've gained some important beachheads in the science, but we've also made very little progress towards translating this toward what we all often speak of as the "full potential" of nanotechnology. Going forward, I think the challenge is to breach this chasm and, as Angela and the others have said, actually translate this into stuff that affects our everyday lives. So that's what the "middle" is… it's using the building blocks of individual atoms, molecules, individual nanostructures, and assembling them into larger-scale systems with emergent functionality that will be of great use to humankind.
TKF: Angela, I'm glad you touched on the cross-disciplinary aspect of nanoscience. In your area in particular, you seem to be blurring the line between living things such as viruses and machines. And from what you just said, I was wondering how you would see this middle scale would apply to things like using viruses, for instance, to create nanostructures?
Angela Belcher: One of the beautiful things about biology is that biology functions at many different length scales, and all of those length scales are working together to make the being functional. So if you think about down to the molecular scale, to DNA and coding and genetic information, to protein that the genetic information codes, to tissues that it builds up to functional levels -- you know, human beings walking around -- it's pretty fascinating to think about how all that works together. But it is all basically encoded in these molecules within cells. We've spent a lot of time looking at how to control genetic information in things that are viruses, that are relatively large – they're six nanometers by almost a micron in length – trying to figure out how to manipulate their genetic information so that they can do what we want them to do, like grow a battery or grow a solar cell. But ultimately what we're trying to do is produce a material or a device that you can hold in your hand that can be useful. So we're not making a solar cell, you know, that's nano in size; but we're making it out of nano-components that can be scaled, or the same with lithium ion batteries, for example. So the challenge is to work with something that small but then scale it up to something that you can use as a very practical device.
Comment by Michael Roukes: The area that I'm particularly interested in, and the center of gravity that my own research is moving towards, is the use of nanoscience and nanotechnology to enable new frontiers in the life sciences and medicine. We often speak of this as "nano-for-bio." And the reason why it's important is that nanodevices, nanostructures, are on the same scale as the atoms and the molecules that form the basis of biological processes. So we can think about getting our hands on things down at that scale – measuring them, manipulating them. You might say that this is already being addressed by modern techniques in molecular biology, but typically this is done one step at a time. Instead we look forward to understanding the larger picture through technology that is capable of embracing the complexity of biological systems. We can't understand the big picture by averaging over everything that's happening. We need to follow a multitude of details simultaneously. And what nanoscience and nanotechnology, uniquely, have to offer is using technology at the bottom, as Feynman envisaged, at the level of individual molecules, but scaling it up into complex systems that will allow us, as I said, to probe and manipulate complex biological systems. This will allow us to understand how the whole hierarchy is put together. And this is an especially exciting frontier for nanotechnology, or what's being called the nanobiotechnology of the future.
TKF: Speaking to David now, and pursuing this idea of the "middle." In your work – and you're especially known for spintronics, which is quantum-level work, obviously – what do you see as the extension of your research into this zone, where you're above the atomic scale?
This image shows how "spintronics" researchers such as David Awschalom probe and manipulate single electron spins in semiconductors. Scientists in this field are now able to image and control a single spin at gigahertz frequencies with high fidelity. (Source: David Awschalom)
David Awschalom: In nascent areas such as spintronics where we're attempting to precisely control a fundamental quantum mechanical variable, spin --- which really doesn't have a classical analogue -- we want to think about building objects using individual atoms or electrons as building blocks. But as Angela said, bringing this physics to a macroscopic scale for applications in the real world is an exciting challenge. And this raises many very interesting scientific questions, such as how large can you make a quantum object, how do quantum objects interact with the real world, and, in the end, can you use the physics that comes out of this research to design new materials that enable unique functions such as quantum entanglement and teleportation? At the same time materials science is rapidly developing into a cross-disciplinary discipline that drives this research area. Materials can be inorganic, organic, or hybrid combinations of the two with properties that can be tuned at the atomic scale with the guidance of remarkably predictive theoretical modeling. Being able to create materials from the ground up is opening vast new opportunities in this "middle" area in contrast to our traditional classification of materials. Again, old distinctions become blurred in this arena.
To me, the middle ground "frontier" is how you maintain quantum mechanical behavior of an object as you bring it to a macroscopic scale. And one of the exciting things about nanoscience is as we learn more about materials and their interactions with their surroundings, some of the technical challenges for quantum control that we thought would be extremely difficult to overcome are turning out to be simpler, for reasons which aren't yet obvious. I believe that this middle ground is one of the most exciting fields of research – it's where scientists and engineers will bring quantum physics to macroscopic objects, and then imagine how these objects could interact and ultimately play a role in the real world.
TKF: Don, you're probably best known for going to extremely small scales -- obviously the feat of spelling out "IBM" with atoms, and so forth. It seems that your work has always tended to go towards the very small. How in your research recently have you – if this is happening – been pulled to look at the middle, to look at the larger scales?
Donald Eigler: Atom manipulation is just a tool in the laboratory that lets us explore and learn things. Let me just give you two specific examples of things we've done which are very much in line with this exploration of larger quantum systems that David just mentioned.
One of the things that we did was to build a linear chain of 10 manganese atoms and then determine that the spin properties of that chain were global – that it was a quantum-coherent spin system over the entire chain of 10 atoms. That, of course, leads to the question, how far can you go? How far can you maintain the integrity of a quantum state and under what conditions? That's something that is waiting to be explored.
Why are we so interested in exploring quantum systems? I think David mentioned it, but let me reinforce it: Quantum systems can have uniquely different properties which allow us to do things that we cannot do with classical systems, or to do things in perhaps a different and better way. One topic that so many people are interested in is quantum information processing. But even without going to quantum information processing, quantum systems can sometimes do things that are classically useful, but do them in ways that could be really beneficial. Let me give you a specific example. Some time ago we built a particular shape quantum corral which allowed us to send two channels of information right through one another in a solid. Now that has the potential of being technologically important. If we could incorporate that in our information processing technology, it could have a very significant impact on the technology's cost structure. That's because we have to move a lot of information around inside a chip, and that means we've got to have a lot of wires to move the information. We can't let classical wires pass through one another and expect them to carry independent channels of information, but quantum corrals have demonstrated a way to do precisely that. That's the kind of opportunity that lies before us.
Comment by Michael Roukes: What Don talked about -- that scaling up the work of manipulating individual atoms allows us to begin to start looking at artificially constructed molecules, and looking at their properties and scaling up to even larger systems – also holds true when we think about using nanosensors for studying the details of biological systems. Over the course of more than a decade, my group has developed the capability of weighing individual molecules one-by-one with little nanodevices. This has opened up a really wonderful new territory to explore -- the underlying physics of making such precision measurements. But the real impetus for pursuing this is not to measure just individual molecules one by one, but in the billions or hundreds of billions-fold, so [that] we begin to understand, for example, what all the proteins of an individual cell are doing. And the only way we can possibly do that is by taking the unit, sort of, nanotechnology-based sensor that's been created in the academic setting and transferring it and scaling it up for production within the billion-dollar scale microelectronics foundries that build computer chips. These are already capable of building chips with billions of individual entities, the transistors. We want to leverage that technology, in some sense, away from the strong Moore's Law-like push towards advanced, complex computer systems into a different applications realm terrain. This new realim is assembling very complex labs-on-a-chip for for applications in the life science and medicine – to enable us to monitor, ultimately, billions of biological operations per second.
TKF: It also seems, doesn't it, that you're working toward solving this problem of heat that has to be dissipated in very small-scale operations. And that's an issue that Feynman himself was talking about in his lecture as being a potential issue.
This "quantum corral" in the form of crossed ellipses was used by Don Eigler and his research team to demonstrate the ability to send two channels of information through one another by exploiting the quantum properties that are a consequence of the small size of the corral. (Credit: IBM Corporation)
Donald Eigler: I hold the belief – and I think many of my colleagues hold the belief – that we will learn ways to do computation in extremely small structures with much less energy dissipation per computational task. Call it a matter of faith.
David Awschalom: I think that's absolutely true. When you imagine quantum objects, and the dynamics at their relevant length scales, electrons, nuclei and individual photons all come together and interact by exchanging information with one another. We can begin to think about information very differently than we have done in the past (with classical machines). And I am confident that there will be many surprises in this area of research. In fact, in terms of heat dissipation, one unexpected discovery that has recently occurred is that, when you start to heat certain types of magnetic semiconductor structures the heat itself generates spin polarization: the system uses the phonons to generate polarized electron states. In this way you might imagine recycling heat in electronics to actually generate quantum states that can be used for new applications. Or maybe run the process backwards, and use quantum states to extract heat. We have to learn to think about the behavior of matter very differently at reduced length scales.
Comment by Michael Roukes: I think this is a really interesting point that compares Feynman's vision with what was unveiled by laboratories over the intervening five decades. We discovered in my own lab – with my former post-doc Keith Schwab, now a professor at Caltech – that there is a fundamental limit to the rate of heat transfer. In other words, there's a quantum of thermal conductance. And this quantized thermal conductance is one of the "rules" that nano-engineers of the future will have to have in their back pockets when they engineer this heat dissipation problem at the molecular scale. A similar sort of rule, or law, that was unveiled in the past few decades was the quantization of electrical conductance. A third area that's been very interesting, and fodder for an immense amount of physics research, has been how the nature of the discreteness of the electron charge – how single charges being transferred from point to point in different devices-- can actually the performance. As devices get very small, one has to take these rules into account. This granularity of nature, these quanta, the discreteness of electrical charge, is strongly manifested, even dominant with scaling of devices down to the domain of nano. It requires us to rethink what the rules of engagement are for building … the building blocks, the individual devices, and for aggregating these building blocks into larger systems. Understanding these rules is core to how we must build future complex systems using nanotechnology.
TKF: Let's put on our Feynman hats here and try to look well into the future. What do you see as potentially possible in 10 or 20 years in terms of nanotechnology? I'll start with Angela this time.
Angela Belcher: I think a lot can happen. Some of the things that I hope can happen have to do maybe less with discovery and more with manufacturing, and specifically clean manufacturing of materials with new routes to synthesis of materials, less waste and self-assembling materials That's one level of the kind of things I would be excited about. It's happening right now, if you look at manufacturing of certain materials for, say, batteries for vehicles, which is based on nanostructuring of materials and getting the right combination of materials together at the nanoscale. Imagine what a big impact that could have in the environment in terms of reducing fossil fuels. So clean manufacturing is one area where I think we will definitely see advances in the next 10 years or so.
TKF: You've also looked recently into the conversion of CO2, into carbonates, and so forth. Is that something you see happening feasibly in the next few years?
Angela Belcher: Well, it's an area at the interface of nanoscience and nanotechnology for sure I think there are going to be multiple solutions, multiple ways to try to address the problem of CO2. In our case, what we're doing is trying to re-program organisms to take the CO2 and make building supplies from it instead, and we've been successful in doing that. But it's a question of scale. You need to do it on a scale that makes a big enough impact in the environment, and in our case we don't know that yet.
TKF: What are everyone else's thoughts about what we might see 10 or 20 years from now?
David Awschalom: I would love to see, in the next decade or two, the emergence of a genuine quantum technology. I'm thinking about possible multifunctional systems that combine logic, storage, communication as powerful quantum objects based on single particles in nature. And whether this is rooted in a biological system, or a chemical system, or a solid state system may not matter and may lead to revolutionary applications in technology, medicine, energy, or other areas. But I think Angela's right. At the end of the day it may be an economic or manufacturing argument that determines the future course of action, but I find that it's exciting to think about a real quantum mechanical technology that obviates some of the worries about energy dissipation, and in which storage densities can be arbitrarily large based on single particles. And – thinking boldly – imagine that you could use a simple quantum machine to solve the Schroedinger equation. If successful, suddenly one could design new materials with special properties, and new pharmaceuticals; things would be very, very different in our world with these capabilities. I believe that these breakthroughs will happen, but it's not clear how we will achieve them – and that's part of the excitement of our fields.
Donald Eigler: I think the impact of nanoscience in medicine is going to grow dramatically over the next 10 to 20 years, especially in the field of regenerative medicine. Another thing that I am hopeful about is that we will be able to hijack the brilliant mechanisms of biology to construct for us functional non-biological nanosystems. In my dreams I can imagine some environmentally safe virus, which, by design, manufactures and spits out a 64-bit adder. We then just flow the virus's effluent over our chips and have the adders attach in just the right places. That's pretty farfetched stuff, but I think it less farfetched than Feynman in '59.
Comment from Michael Roukes: There are many things that are very exciting about being able to control things at the atomic scale and then, from the bottom, build back to the middle to creating complex systems with just incredibly exquisite control about what these complex systems do. And one area that's absolutely ripe for incredible advances is the life sciences and medicine, where aggregations of individual nanodevices to create nanosystems will allow us to embrace, rather than run away from, the complexity of biological systems and will give us the tools, I believe, to understand and engineer biological circuitry, which as the root of systems biology and ultimately, I think, will give a technological foundation for personalized medicine.
TKF: How do you see nanoscience itself changing? Is the science going to look substantially different in the way you label yourselves and how you define what you're doing in, say, 10 or 20 years?
Donald Eigler: I'll take a stab at that, and give you a non-answer: I hate labels. I think labels are totally counterproductive. It is what you do and what you learn and how you contribute that count. You can put whatever label you want to on things, but often they are divisive, and don't really help.
TKF: David, you're a physicist, and we have people in this conversation who are tied to biology in a lot of ways. In fact, there seems to be a wide range of disciplines that are historically quite different that are involved in nanoscience. But do they actually come together in really collaborative ways?
David Aschalom: Actually, yes. I believe that the broad umbrella of nanoscience is rapidly dissolving the traditional barriers between these disciplines, and maybe wiring them a bit together with the idea that now people are thinking about atoms and materials as arbitrary forms, not in the historical sense. Physicists are now using biological systems, and biologists are exploiting solid state devices and microfluidic devices within a myriad of research efforts. People are thinking much more broadly than in the past and, as Don says, I think it's the discoveries in science that are driving this direction. When I look at the students who are entering the university system, they're highly motivated by the idea of breaking down the normal barriers and focusing on the new scientific opportunities that emerge. I agree with Don. I think the idea of labeling things is wrong. This merging is going to happen very naturally. It's already happening. For example, some researchers are thinking about photosynthesis as a quantum process, and [asking] whether photosynthesis is driven quantum mechanically in certain plants – exploring the concept of coherent energy transfer in biology. If so, it is possible to control this flow with exquisite precision. When you look in the literature, there are growing numbers of laboratories working in these cross-disciplinary areas; not because they're suddenly interested in biology but they realize that biological systems could be tuned and engineered to explore unique scientific missions. So yes, I do believe that this merge is inevitable. I don't think it's going to be because of funding, or because of labeling, as Don says, but it's where the interest is, and it where the new frontiers are in science.
Comment by Michael Roukes: Nanoscience has really been focused for the last couple of decades on unit physical effects and unit devices, and on the engineering of individual types of molecules or nanoparticles. I think the nanoscience or nanotechnology of the future, again, has to involve thinking, in a systematic way, about putting these individual building blocks together in a coherent way to achieve emergent functionality. David and Don talked about how quantum mechanics can be manifested on a macroscopic scale, and so there's a literal interpretation here of what a coherent nanosystem would be – coherent in the quantum-mechanical sense, where the whole system is acting as a quantum-mechanically. But, in the biological sector quantum coherence is generally less important than achieving systems with a comparable level of complexity as the biological systems they're designed to probe. This kind of systems coherence will allow us to unravel the complex and interacting concatenation of individual biological processes that, for example, give cells life.
TKF: Angela, from your perspective where do you see the physics-biology interface occurring?
Angela Belcher: I also agree that the interface is where everything is happening As a young scientist I used to remember trying to change fields and being told, oh no, you have to stay in the same field that you are in. And now it's very common that students will get their bachelor's degree in one field and their PhD in a different field because we're so much more open to the idea that these disciplines do merge. And I also think of it from a problem point of view. To take the example of photosynthesis – well, that's a problem. What tools can you bring, what disciplines can you bring together to help solve this problem or to look at it in a new perspective? People will always say to me "What do you call yourself?" and I agree with Don that labels aren't very helpful; it's how you think and what you can bring to solve a problem. I've seen that shift personally, pretty strongly in the last 10 to 15 years, to the point where students now are encouraged to get expertise in more than one field and merge them together, because it's at that blurring of the interfaces where a lot of progress can be made. Facing a problem and looking at it in just a completely different way can really pull out some new, fundamental ideas of how a process works and what you can actually bring to solve the problem. I'm excited about [this trend]. I think it's only going to get better.
Comment by Michael Roukes: I totally agree with what Angela and David said -- students are sniffing out and finding these exciting interfaces. They are pushing back, basically, against the traditional academic barriers between disciplines and towards their coalescence. Work at the interfaces are absolutely critical, because this is where the frontiers of nanoscience are. Pursuing them very literally requires having people with complementary expertise sitting around a table, in dialog to begin developing a common language and all turning their attention towards one common, high-value problem. When I started working in the area of biosensors about 10 years ago – in a close collaboration with Scott Fraser, who's a professor of biology here – we began to have these kinds of weekly ubergroup meetings. It was so exciting and so transformational, I made the decision then that this is where I want to "live" for the entirety of my career – right at these interfaces. Because there's so much benefit to the sharing and understanding different people's perspectives, and then to engage in the common pursuit of a worthy problem.
TKF: Don, you said medical advances, or medical uses of nanotechnology, could really take off. I wonder if you could elaborate on that and if we could get some thoughts from the others.
In contrast to conventional nanometer-scale quantum dot nanostructures that can hold a single electron, this image shows chemically-synthesized assemblies of integrated quantum dot structures that can communicate via photons. Each quantum dot consists of coupled spherical quantum wells, each in turn containing a single electron spin. By tuning the excitation and probe energies, scientists can selectively initialize and read out spins in different coupled states within the entity. These results open a pathway for engineering coupled qubits (quantum bits) within a single nanostructure. (Courtesy: UC Santa Barbara)
Donald Eigler: Let me just briefly talk a little bit about some of Sam Stupp's stuff. Sam [director of the Institute for BioNanotechnology in Medicine at Northwestern University] is a supramolecular chemist – although I just put a label on somebody; I should shoot myself [laughs] – Sam is a guy who likes to build molecules. He learned how to build a certain kind of die-block molecule which has as part of the molecule a sequence of amino acids. The cool thing is that under the right conditions these molecules self-assemble into long fibrils. How does that impact medicine? Well, you can use sequences of amino acids to signal cells to do things. As an example, Sam built these molecules with the sequence of five amino acids that signal neurons to grow like crazy. These can be injected into spinal cord lesions and, as a consequence, stimulate very rapid regrowth of damaged neurons. In a tour-de-force experiment, Sam demonstrated the reversal of paralysis through the stimulated regrowth of damaged neurons -- a very exciting result that points to the opportunities that lie ahead.
Angela Belcher: I also see this as a really fantastic area. It's a very natural area for nano, because again, as Don said, you have a cell, and these cells have receptors on them or signals on them. The cell is on the micron level, but what is on the surface of the cell -- and how those molecules are arranged on the surface of the cell -- that's below micron level, that's nanometer level. If you think about materials and other biologicals that you want to design to grab information from that cell, to have some influence on it, you're going to have to be very small. You're going to have to be patterned at a sub-micron level. If you think about nanoscience in this perspective, it's about how do you put multiple really small things together. When you're sending in a kind of drug or a marker, it's not just one material. Maybe it has a metal on it to heat it up to allow it to enter the cell; maybe it has a receptor that docks on the cell and allows it to come in; maybe it has some molecules on it to make it stealthy, to try to get past the immune system, and things like that. You need to put all these really small components together to go in and have this really smart effect on whatever the nanomaterial is targeting: it's specific, it's killing, it's bringing a drug, it has all these different components to it, all in a really, really small system. You also want to think in terms of, well, how do you get information out? Do you get magnetic information out? Do you get optical information out? A lot of the properties that you want to probe in a way that is the least toxic to the organism or the person are going to be based on signals that come from nanomaterials.
That's internal. But think about the external side. We want to be able to have personalized medicine, we want to be able to have cheap medicine, we want to be able to have a way of diagnosing people where you only need one molecule to tell that something has gone awry. And in that case, how do you collect a very, very rare event out of a person's blood and be able to amplify that up to a signal that is a definite signal, that's a yes or no – i.e., this person has to go for this kind of treatment -- that's going to involve very small volumes, really specific readouts? I think bedside diagnostics as well as personal medicine are going to be greatly influenced by materials and nanomaterials in the next 10 to 20 years.
Comment by Michael Roukes: We understand more and more, from looking at medicine and the development of new pharmaceuticals, that the old paradigm of a blockbuster drug, a "one size fits all" that's going to cure cancer, seriously underestimates the complexity of the world. It oversimplifies the challenge of simultaneously addressing intractable diseases – in particular cancer or AIDS, which require simultaneous battles on multiple fronts. These are multi-headed beasts that are adept at mutating and metamorphosing themselves in ways that render very quickly any single palliative useless. To understanding how to do this requires understanding complex biological circuits, somewhat in the spirit of those within computers. Today's methodology of approach is not really up the task of doing this. Few of the biological analogues of logic gates have been adequately characterized. Without this one can't begin to assemble understanding of biological function at the circuit level. In other words, these circuit diagrams cannot be in sufficient detail to provide predictive power. With development of future abilities to assemble nanodevices coherently into a complex whole, we will be able to build and understand biological circuits. I stress the importance of predictive power, of course, because if you understand the circuits, you understand sort of the pressure points that can be applied, where you might go in and shut off disease pathways and, perhaps even do this at four or five different fronts at once to, sort of, take away the ability of these various diseases to mutate and work around individual pressure points that traditionally have been addressed by blockbuster drugs.
TKF: David, how does the quantum realm enter into this?
David Awschalom: I think it enters in a way that follows from what Angela was saying. Imagine the opportunities that are unfolding in the area of microfluidics and the possibilities of having inexpensive chip-scale objects that can perform dozens of medical tests simply by scaling to the submicron level. Preventative medicine, home blood tests and real-time online analysis… the opportunities are incredible. And one of the things that many of these diagnostics may rely on is being able, as Angela pointed out, to identify small numbers if specific entities out of large volumes. And here we can take advantage quantum probes for sensing – not simply for computation or logic, but having an atomic-scale sensor that can be specifically targeted in one way or another will be very important. I believe that the quantum world will have a large role on sensing, detection, and possibly even targeted repair. Quantum variables are extremely sensitive to their environment at the scale of single electrons.
TKF: Here are a couple of questions about you personally and your view of science. First, do you have some goal, some discovery or some question that you passionately want to see answered? Extending that, do you think that there is sort of a holy grail out there, some breakthrough that nanoscience most needs?
Donald Eigler: First, I don't see that there is one holy grail at all. The world is too diverse. There are so many different things that you can do or have the potential to do with nanometer-scale structures that I don't think there's one holy grail. All that really drives an individual is the "problem du jour." It's what they're working on, and what they're excited about at the moment that is the thing that really drives progress.
TKF: What's your "problem du jour"?
Donald Eigler: I want to build computers that utilize just the spin degree of freedom to do computation – what I call "spin-only" computers. The reason is that I'm really curious about how they might work, what they might be able to do, what are the advantages – or disadvantages – they might have. This is an area that we need to explore – or should I say it's an area I need to explore.
David Awschalom: It makes me very happy to hear that Don is interested in building spin-based computers! Then I view one of my goals as already having been met, which is to get people interested in the spin degree of freedom for quantum machines. I also agree very much with Don – I think there are so many "grails" out there that it's hard to pick one. And in my own field, many of the most important discoveries have been largely accidental. You need to keep searching, exploring. But in my one view, one of the things that has been very exciting within the last few years is trying to build quantum machines to process information through a combination of light and matter under ambient conditions. One of the somewhat fortuitous discoveries that has happened recently is that in some systems - materials that have been around us for generations, such as diamond - it is possible to use the inherent defects to harness quantum states. Typically, people have been working very hard to make defect-free materials for efficient devices in current technology. In diamonds, for example, you can easily identify, manipulate and quantum-mechanically control a single electron spin on the desktop, at room temperature, with very high fidelity. Attaining this goal was almost unimaginable several years ago. So it makes you wonder what else in the world might be out there in which quantum control may be possible: maybe defective quantum machines will be the norm. We're very interested in using state of the art computational techniques to help identify appropriate states of matter, whether they are biological or inorganic, where you might be able to build quantum systems and design quantum architectures. Maybe we'll even work with Don in building some spin-based machines combining our physics with his microscopy techniques
Angela Belcher: I don't see a single particular area that is the holy grail. I'm interested in medicine, environment, water and energy. I think those are all areas where nanoscience could have huge potential impact, and it already is. My personal interest is trying to look at nature – how nature has had billions of years to evolve really exquisite structures – and trying to get genetic information to non-living structures so that we can use some of the same principles that biology uses to, for example, having materials able to correct themselves, have materials become better and smarter and more adapted to their environment, have all room-temperature processes and materials using non-toxic solvents that have low impact to the environment – and when you drop your smart phone, having it basically be able to correct itself. Those are the kinds of things I am very interested in. The question is, how do you harness the potential of biology to integrate it into non-biological devices so that we can have some of the great properties that have been evolving over billions of years.
Comment by Michael Roukes: I agree with the others; there isn't just one holy grail, but there are many holy grails that can potentially be achieved by nanoscience and nanotechnology, especially if we move up to what we're calling the "middle." You know, a cure to cancer, a vaccine for HIV – these are things that require … not sort of the one-dimensional or single-front approach of traditional or existing medicine, but require us to approach on multiple fronts simultaneously. Nanoscience and nanotechnology is about making stuff. So my view is that a holy grail in to develop systematic way of mass-producing individual devices and systematically assembling them to create complex functionality.
TKF: What do you hope to see coming out of the new Kavli Futures Symposium in terms of insights, relationships, collaborations or whatever?
Donald Eigler: I find it extremely stimulating to get into a room with some really bright people with diverse skills, who are great at communicating what it is that they're excited about, where the future is, or where the boundaries are that they're pushing back. There's something about that which I don't know how to describe, and I don't know that I can describe to you a direct path between that kind of experience and progress in the lab or progress in our understanding. And yet I'm absolutely convinced that it's an important part of that overall process. Now what's got me really excited about the Kavli Futures Symposium is we have a hell of a lineup of speakers. Listening to them and spending the day with them is pure candy.
David Awschalom: I agree with that, of course. Hopefully, one of the novel outcomes of this symposium will be in motivating some of the best and brightest graduate students to think differently – to have them appreciate what is very exciting in these emerging areas of nanoscience, and to get them even more deeply engaged in the process. Because at the end of the day, these fields are only going to move forward because of them. They are the future of science and technology at the interface of physics, biology, and materials science. I think Don and Michael have co-opted an extraordinary group of speakers, and the symposium will be a fantastic opportunity to engage students and the public.
Angela Belcher: I don't have much more to add except for combining those two ideas together, because the speakers in the symposium are very interdisciplinary, very engaged people. Their enthusiasm for what they do in the fields in general is contagious, and I agree with David – we need people who are going to rise and move beyond us. And those are the undergraduates, the graduate students that will be there. This exchange of ideas between the researchers who are younger and the more established researchers is just going to be a very fun time. I think that new collaborations will come out of it, but I also look forward just to the general excitement and lifting of the community based on people coming to share their ideas.
Comment by Michael Roukes: My hope is that this will help engender a looking-up from the trenches of unit individual nanoscience into thinking about, and developing a collective passion for nanosystems. Let's think about the middle, and how we can leverage the advances that we've collectively made to the next level [to] allow us to embrace complexity, for applications spanning the life science and medicine, to information, to communication.
TKF: One question for Angela. You were there at the first Kavli Futures Symposium at Ilulissat in Greenland, where the topic was synthetic biology, so this will be your second Futures Symposium experience. How would you compare the two?
Angela Belcher: I consider Ilulissat to be one of the most interesting symposiums I've been to. I think that it brought together a more diverse group of people that had me thinking really far outside of what I normally thought about. It will be interesting to see how this one compares, because I know most of the people in this symposium. But that one had a very big impact on me, so I'm looking forward to the second one.
TKF: Does anyone have a favorite Feynman quote you want to share with us?
Donald Eigler: It's from "There's Plenty of Room at the Bottom," when Feynman's asking the question of whether we can arrange individual atoms "all the way down." The reason why that's my favorite Feynman quote is, I think, fairly obvious. It's because, within 48 hours after I moved the first atom, I was resurrecting this paper from Feynman and looking at it and saying, "Man, this guy had it back in 1959." There it was, atoms being moved.
Angela Belcher: I agree, that's a great one. There are so many that it's hard to choose. But one of the ones I like is that the worthwhile problems are the ones you can really help solve, the ones you can really contribute something to. As an engineer, to me that's what it's all about – trying to solve a problem to help make a difference in the world.
David Awschalom: There are a lots of quotes that come to mind. But one that I'm fond of and that I preach to my students is that the core of science is based on the belief in the ignorance of experts in your field – that you should always be skeptical, be questioning, and think for yourself. When I read the Feynman papers and his biography, I'm always impressed with the fact that he was remarkably independent and pushed his own beliefs to the limit independent of the community response. At the core perhaps that's the way science should always operate.
Comment by Michael Roukes: I have so many … One of my favorites is about scientists basically discovering the beauty and the rules that Mother Nature already has put in place. It's a very interesting perspective. Sometimes scientists promote a more aggressive/arrogant view that scientists are little demigods themselves, and create things that haven't been existed before. Feynman's quote leads me to think he viewed the path of exploration as one leading to the unveiling of the pre-existing, yet wonderful rules of our universe. In other words, we do create, but with the rules that exist, from Mother Nature. Even if we create entirely novel artificial structures, for example, if we put molecules together, these only stay together according to the rules of quantum mechanics. These are not rules that we have created, but these are rules that we have discovered.
It's really a pleasure to have assembled this spectacular group of people. When Don approached the speakers and asked them to contribute an altruistic vision for the future, to a person they all pretty much said, "Wow, what a great opportunity; I'd be so happy to do this." So I have huge anticipation for a day that I hope will explode our collective imagination about where this field can go. And it's fitting, on the heels of the first half century after Feynman enunciated his vision of "plenty of room at the bottom", to think about what the next 50 years might bring!
TKF: Thank you. This has been a great conversation.
Source: Kavli Foundation
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