The avant garde of nanotechnology is driven by a half-dozen laboratories that seem locked in a fierce competition to move the field forward one step of technological wizardry after the next. Harvard University chemist Charles M. Lieber is among the perennial front-runners in this race. In this issue’s lead story, in fact, Lieber rates among the top five most-cited nanotechnology authors of the last decade. And in the Chemistry Top Ten, Lieber’s laboratory can claim the paper currently ranked at #4. In the past decade alone, Lieber and coauthors have generated more than 20 articles with at least 100 citations each. Lieber’s citation-classic "Experimental realization of the covalent solid carbon nitride" (Science, 261[5119]: 334-7, 1993) has been cited nearly 600 times (see the table below).

Lieber, now 44, obtained his bachelor’s degree in chemistry from Franklin & Marshall College in 1981 and then went on to Stanford for his doctorate in 1985. After doing two years of postdoctoral research at Caltech, he became an assistant professor of chemistry at Columbia. In 1991, he moved to Harvard, where he now holds the Mark Hyman, Jr. Chair of Chemistry.

In the 1980s you were working on surface chemistry and high-temperature superconductors. What prompted your move into nanotechnology?

When I moved to Harvard in 1991, I became very interested in a simple question: why can’t I just make a one-dimensional wire? Until that time, with my work on high-temperature superconductors, I had been studying quasi-two-dimensional planar structures, and quasi-one-dimensional materials, and we were studying the effects of dimensionality and anisotropy on their material properties. And I was thinking, Why do I always have to add these caveats to everything I’m doing. It’s always "quasi this, quasi that." Also, at the same time, interesting work was going on with fullerenes and carbon nanotubes. Nanoclusters were floating around then, too, and I just started thinking about what I could do that was unique, and about the really important problems other than what everyone else was then working on.

I don’t know if people were even calling this field "nanotechnology" at that time, but I thought that if a technology was ever going to emerge from all these concepts, it would require interconnections—exceedingly small, wire-like structures to move information around, move electrons around, and connect devices together. Nanowires or something like them were going to be absolutely essential, and I figured I might as well go for it.

What do you think is the best bet for a technology to build and assemble nanoscaled devices and chips?

Well, we’re primarily focused on assembly-based methods. This shouldn’t be confused with self-assembly. "Directed assembly" is a better way of describing it. A simple example would be one we recently published, which was a pattern of chemical receptors on a surface. If you’re just doing self-assembly, you put complements to those receptors in solution and have them find the receptor sites that you pattern in advance on the substrate. In principle, it can work okay with spherical objects where the orientation doesn’t really matter. Imagine trying to lay down a long wire, however. With self-assembly, you would have to allow them to come down arbitrarily and fit into the receptors, and it's not always going to give you the structure you need. We use fluid flow to direct the assembly. So, for instance, you can use fluid flow to align nanoscale wires along the direction of the chemical receptors, which are patterned, say, in stripes on a substrate. So now you’re using fluid flow to direct the assembly in the orientation you prefer.

Looking at the history of the field over the past five years, it seems that there are four or five labs that are competing pretty ferociously to get to the next step. Does that competition affect your work?

It’s probably true to say that, at times, the competition is fairly intense. But it doesn’t necessarily affect the research as much as it affects how happy I am at times. I am a very competitive person, so I am very unhappy when I’m not first. It also adds pressure. I definitely feel more pressure to get things done quickly and—ideally—first.

What do you think are realistic projections for what we can expect from nanotechnology in the next few years?

Well, it’s hard to predict, of course. As a scientist, I think that my goal is to try to push this science in ways that will ultimately turn it into a working technology. A lot of that work is focused on the perspective of integrative systems and being able to build systems to create unique functions. One example would be combining optical and electronic function in a nanoscale device. Things I would like to do in the short term include, for instance, making a real integrated sensing device, which could be used in a very generic sense for screening, say in disease applications or chemical warfare. That’s probably something that can be done in the next five years. You could use existing electronics as a driver and small-scale processor and still do that in very simple kinds of devices.

Another possibility is some kind of stand-alone information-processing system. That’s certainly one of our biggest goals. Again, it involves all the key aspects of what’s important in nanoscience: first being able to make the materials; then being able to make well-designed devices out of those materials; being able to assemble integrated structures, which then have this device behavior reproduced in larger arrays; and, finally, somehow being able to interconnect from this small-scale array to the large scale where you connect to the outside world. Even a very simple system is complicated to make and may not compete with what’s out there, technology-wise, in digital electronics. Nonetheless, it would be a proof of concept. And one could use this bottom-up approach in nanotechnology to then build integrative systems or nanosystems. You could substitute nanowires, for instance, at any stage in the process to get different functions. That’s the beauty of this technology. You can focus on one problem—digital computing, for instance—but you can see how you would then use similar structures but with different properties, to produce a different device. This is why it’s so important to have a basic material, such as a nanowire, that you can make in a controlled fashion with very different compositions.

Do you think that, eventually, nanotechnology is going to noticeably change our lives?

Tomorrow? No. But I do think in the long term it will change our lives quite significantly and quite positively. It may be by coupling nanotechnology with advances from other areas, such as genomics. Nanotechnology may provide, for example, the ideal technology for enabling very cheap and rapid large-scale sequence analysis. In ways like that it might make a major difference. Yes, I think it will noticeably change our lives. Although the scale of when and exactly how is harder to predict.