Nanotech: Universe In A Grain Of Sand
It was a shining moment. Four years ago in a University of Texas chemistry lab in Austin, two professors, Brian Korgel and Keith P. Johnston, placed bits of silicon in a pressurized titanium chamber. They poured in a brew of solvents and then heated it to 932F. What emerged from this pressure cooker were itsy-bitsy crystals of silicon, visible only under the most powerful microscopes. But something was very peculiar about silicon at this atomic scale. It wasn't its usual sandy self. Far from it. These so-called nanocrystals, when hitched to electrical current, emitted steady light. That glow attracted venture capitalists. Hungry for advances in the budding field of the ever-so-tiny -- nanotechnology -- they financed a lighting startup, InnovaLight Inc., and pushed the inventors to file a dozen patents. These days the new company, based in the dry hills west of Austin, is engineering those crystals for the marketplace. These specks are as tiny next to a soccer ball as that ball is to earth. Yet InnovaLight is betting that gazillions of them eventually will light up homes and offices. "We want to replace the light bulb," says InnovaLight CEO Paul Thurk.
In labs throughout the world, from research universities to blue-chip multinationals, scientists are weaving nanoparticles -- measured by the billionth of a meter -- into outsized dreams. They see these bits eventually targeting and destroying cancerous tumors, revolutionizing electricity generation with ultra-efficient solar cells, and forming into platoons of microscopic disease monitors to be deployed inside the human body. They're planning for the day when semiconductors built of nanoparticles replace silicon -- and usher in an age of computers powerful enough to rival the human mind. There's even a plan to link earth to a space station with a pillar built of superstrong nano materials, stretching thousands of miles straight up.
A VAST CHEMISTRY SET
These outsize ambitions would amount to a dizzying to-do list for any single technology. But that's where nano's name sows confusion. Think of nano not as a technology but as a minute scale of engineering. An assortment of marvelous tools -- from atomic-force microscopes to powerful imaging software -- has cast open the doors of the atomic world to researchers everywhere. This gives them a rich universe to explore. Three centuries ago, scientists marked a similar advance when they peered through the first microscopes and witnessed the teeming world of microbes and protozoa. That set them on the path to modern medicine. Their heirs today have first crack at manipulating the very building blocks of matter.
The job ahead, which promises to be a defining enterprise for the 21st century, is to reengineer, atom by atom, the physical world. Why bother? Scientists are discovering every day that even familiar materials can behave altogether differently when reduced to ultratiny pieces. Break down gold into small enough bits and it becomes a catalyst. Other materials emit light or turn into superconductors of electricity. Why the differences? Mysteries still abound. While scientists understand that electrical properties undergo transformations at these nano sizes, says Texas' Korgel, they still struggle to understand many of the changes -- and more to predict them.
The result is that nanoscientists face what amounts to a vast chemistry set full of new materials and tantalizing possibilities. Biologists, physicists, chemists, and electrical engineers have the chance to invent materials at the molecular level and create tailor-made metals, fabrics, tissues, and membranes. "Nanoscience is about redoing everything," says Chad A. Mirkin, director of the Nanotechnology Institute at Northwestern University in Evanston, Ill. "Everything, when miniaturized, will be new."
To be sure, the transforming potential of nanotechnology generates its share of hype. Similar revolutions, most recently in biotech, have delivered on only a fraction of their promise. And plenty of nano initiatives are certain to run aground between the lab and the marketplace. InnovaLight's bid to replace the light bulb, for example, is just one in a galaxy of nano long shots. What's more, concerns about nanoparticles polluting the environment could fuel opposition to new materials and create regulatory hurdles. And schemes to unleash nano agents inside the body, whether to zap cancer cells or to break down a diabetic's glucose, must first demonstrate conclusively that the agents won't pile up harmfully in the body or seep -- heaven forbid -- into the brain.
Yet even if certain applications fall flat and timetables run amok, there's no turning back from research on the nano frontier -- not now that scientists the world over are exploring its wonders. Such a retreat would be akin to telling Dutch biologist Antonie van Leeuwenhoek in 1668 to toss his microscope in the nearest canal and settle for squinting at germs with the naked eye. What's more, entire industries are banking on advances in nanotechnology not just for enhancements but for salvation.
Take semiconductors. For decades chipmakers have been shrinking their circuitry and jamming more and more transistors onto wafers of silicon. This relentless process has doubled computing power per chip about every 18 months, as predicted more than three decades ago by Intel Corp. (INTC ) co-founder Gordon E. Moore. But Moore's law may be bumping up against its limits.
Chips are getting mighty crowded. The insulation that protects ultrafine metallic wires is becoming so thin -- in places only a few atoms thick -- that electrons can tunnel through it, hurting performance. Worse, each new transistor generates extra heat. Soon there will be so many that some chips could reach the temperatures of rocket nozzles -- and melt. "We know the road ahead will hold through 2015," says Paolo A. Gargini, Intel's director for technology strategy. "But by 2020 we'll have to enter a new regime."
Enter the carbon nanotube, the closest thing yet to a jack-of-all-trades in the nano world. Discovered 13 years ago by a Japanese researcher, these cylindrical wisps made of carbon atoms are shaping up to be a pillar of the nano age. They are as much as 100 times stronger than steel, and they can be tuned to resist electricity or to conduct it efficiently, emitting little heat. The hope is that nanotubes could provide both the structure and the circuity of a future generation of semiconductors. That would give the chip industry a new lease on life. And the resulting explosion of computing power would fuel innovations in every field of science. Think of modeling the brain, of planting immense computing power into artificial ears and eyes, of forecasts that pinpoint the path of tomorrow's tornadoes.
Tech companies are just starting to piece together this vision. At IBM's Thomas J. Watson Research Center, researchers have assembled prototype nanocircuits. But they're still far away from a mass-scale technology that could power the $200 billion chip industry. "Going from lab to development to production, there are many oceans to cross," says Venu Menon, Texas Instruments' (TXN ) vice-president for silicon technology development.
For the next decade, look for nanotubes to take up supporting roles in computing -- starting with a splash in memory. At a Woburn (Mass.) startup called Nantero Inc., researchers are putting together a high-performance memory stash made entirely of nanotubes. Billions of them are dropped on a chip, like a microscopic plate of spaghetti. Within this thicket, each strand can capture a bit of digital information, bending to form the one and staying flat for zero. Nantero, which is nearing the manufacturing stage, aims eventually to develop chips that pack a terabyte of data -- 1,000 gigabytes, about the contents of a municipal library -- onto a space the size of a credit card.
The miracles of miniaturization will provide medical researchers with powerful new tools, from arrays of tiny sensors to minuscule drug dispensers lodged in the body. This is nanobiotech. Despite fears of nano agents going haywire, research races ahead. In labs in Hayward, Calif., scientists at QuantumDot Corp. are experimenting with "q-dots" -- nano-size semiconductors that glow in different colors. By tweaking their size and coating, researchers can dispatch particles to different kinds of cells. In studies, the q-dots have lit up the lymph systems of pigs in great detail, making it easy for doctors to identify diseased areas. Others hope to use the same process to target and cook cancer cells.
That's ambitious, but it's not in the rarified league of the space elevator. The idea is that the immense strength of carbon nanotubes would allow for the construction of a singular skinny beam a yard wide and tens of thousands of miles long. This pillar would extend straight up, like Jack's beanstalk, far beyond earth's atmosphere and hitch to a space station hovering in geosynchronous orbit. Little pods would shimmy up and down this stalk with provisions, carrying out the work now handled by rocket launches -- for one-thousandth the cost.
Yes, it sounds absurd. But NASA-backed researchers aren't laughing. They're busy studying how to weave nanotubes into threads -- and those threads could later become cables. The nano frontier, they know, will be alive with surprises, many of them still beyond imagination. And who knows? If nano makes good on even a handful of today's visions, from replacing silicon to fighting cancer, someday the space elevator might sound like a sensible idea.
By Stephen Baker and Adam Aston