Manufacturing Nanotech Wonders

Transcript

In 2006 alone, governments, corporations, and venture capitalists invested $12 billion in nanotechnology research and development worldwide. And that investment is already producing astonishing scientific advances with great commercial potential in producing semiconductors, storing data, generating energy, and diagnosing and treating diseases.

The implications for business and society are enormous. But why are nanotechnologists so fixated on size - and why should you be? In the 1960s, we used to hear that "small is beautiful." With nanotechnology, small is also powerful, effective, and environmentally friendly.

David Rejeski, director of the Project on Emerging Nanotechnologies at Washington's Woodrow Wilson International Center for Scholars, says: Nanotechnology promises to change just about everything - our medical care, energy sources, communications, and food. It's leading us to what many in government and industry are calling - The Next Industrial Revolution.

Consider nanotech's role in the crucial semiconductor business, which is starting to run into a brick wall with traditional manufacturing methods. Without nanosized materials, the industry can't proceed with its trademark approach of increasing power and decreasing product costs every 18 months, as dictated by Moore's Law.

Finally, with cancer and other diseases, there's a pressing need to stop treating people with approaches such as radiation and chemotherapy that kill healthy tissue along with the unhealthy variety. Nanotechnology promises a laser-like approach - eradicating bad cells without hurting good ones.

Mass-produced materials employing carbon nanotubes and other nanoparticles will soon become mainstream. However, true nanodevices generally still get meticulously built in laboratories one molecule at a time. Why? Because the technology to mass-produce complex structures at the nano level - quickly, cheaply, and reliably - hasn't existed.

However, as we'll explain, that's all changing rapidly. Scientists are learning how to solve the problems that have prevented them from producing complex nanodevices cheaply, safely, and quickly.

One major challenge is the tedious nature of traditional nanoproduction, which has prevented it from taking place at industrial levels. To address this challenge, scientists are working on several different ways to control the assembly of nanoparticles, which are defined as smaller than 100 nanometers.

At the same time, they are trying to eliminate the damaging effects of some of the most common molecules currently used in nanotech, such as gold. Finally, they are trying to overcome the problem of powering nanodevices operating in the body or free in the environment. Resolving these problems will lead to many important real-world applications in computers, energy, and drugs.

For example, a report from the University of Pennsylvania last summer showed physicists there were using a new technique to form some of the tiniest metal nanostructures ever recorded. None of the structures was larger than 10 nanometers - that is, 10,000 times smaller than the width of a human hair.

Or consider the achievements of scientists at Rensselaer Polytechnic Institute in New York State. They developed a simple way to print patterns of carbon nanotubes on paper and plastic. To do so, they used an off-the-shelf inkjet printer.

That effort could lead to a new process for industrial manufacturing of nanotube devices - from flexible electronics and conducting fabrics to sensors for detecting the presence of chemical agents.

Even more exciting, a team of researchers at Brookhaven National Laboratory is relying on DNA, the molecule that carries genetic instructions. Using synthetic DNA allows them to control both the speed of nanoparticle assembly and the organization of nanoclusters.

Matthew Maye, a Brookhaven chemist, explains what's happening with nanoparticles: "They're usually free-flowing in solution, but for use in a functional device, they have to be organized in three dimensions, or on surfaces, in a well-controlled manner. That's where self-assembly [with DNA] comes into play. We want the particles to do the work themselves."

In nanotechnology, there's a problem with gold, the substance used generally as a catalyst for nanowires. Gold undermines quality in microelectronic components, and does great damage when it comes in contact with production machines.

Brookhaven tackles the problem with its innovative use of synthetic DNA, relying on its characteristic of linking up with components called bases. Brookhaven caps the DNA onto individual gold nanoparticles, which then bind to complementary DNA located on other particles. The result is nanoclusters, or aggregates of particles.

Previously, Brookhaven used rigid, double-stranded DNA to accelerate or decelerate nanoparticle assembly. Recently, the facility was able to regulate the size of the resulting clusters by incorporating multiple DNA strands.

Physicist Oleg Gang explains what the lab is doing: "In biology, DNA is mainly an informational material, while in nanoscience, DNA is an excellent structural material due to its natural ability to self-assemble according to well-specified programmable rules."

To nonscientists, the process sounds hideously complex. But it's fairly simple, actually. A scientist writes out a known DNA sequence, and then can control how the nanoparticles assemble.

There's another promising approach to the "gold problem." It consists of substituting aluminum for gold. Successful research accomplishing that is taking place at the Max Planck Institute in Germany.

Recently, Planck Institute scientists have developed single crystal silicon nanowires. Silicon nanowires can further reduce the size of microchips. The researchers used aluminum as a catalyst to grow the nanowires.

In the past, scientists generally have relied on gold, which damages semiconductor components. It's been known that some other metals can serve as catalysts, but they function only at very high temperatures, which undermines their economic viability.

Aluminum is different. It serves effectively as a catalyst even at relatively lower temperatures, and doesn't harm the quality of electronic components.

At the University of Arizona, there's a related scientific development underway - one that's essential in making the next generation of extremely small, very powerful computers. The breakthrough consists of turning single molecules into effective transistors.

A transistor is able to turn electrical current on and off. Up until now, manufacturers have used transistors that are as small as 45 nanometers. However, with the University of Arizona achievements, it now should be possible to make transistors that are true nanosize, that is, one billionth of a meter. That's 45 times smaller than today's best technology.

The molecule the Arizona scientists propose using for a transistor is a ring-like one benzene. Their approach is to attach two electrical "leads" to the ring. That would create two alternate paths through which electrical current can flow. They're now exploring the attachment of a third lead that would be the opposite to one of the electrical leads. The third lead is the crucial one, because it would turn the device on and off, functioning like a valve.

Early last summer, researchers reported in Nano Letters, a publication of the American Chemical Society, a new technique related to electric power generation. It could lead to implantable medical devices, sensors, and portable electronics - without the need for bulky batteries.

Instead, electricity for such devices could come from something almost incredible: the contraction of human muscles or other body movements. The study demonstrated power production with nanogenerators fashioned from one zinc oxide nanowire and a nanowire belt.

The power gets generated from the piezoelectric effect, a phenomenon that occurs in materials that transform mechanical energy into electricity - such as flexing a human body.

What are the practical implications of such a discovery? It opens an entire new field of nanotechnology. It points to the possibility of harvesting electricity from human movements — and even from rises and drops in blood pressure.

With advances like these, the prospects for nanotechnology could be even greater than the most optimistic advocates believe. Here's how the Trends editors see that future:

First, miniaturization is the wave of the future, with great promise not only for high-tech enterprises, but also for traditional industries, such as automotive and airlines. In 2005, sales of products based on nanotechnology topped $30 billion around the world. By 2014, the market is expected to expand to $2.6 trillion. With sky-high energy prices, making things smaller is critical to companies' competitiveness.

Smaller products, be they microchips or railroad engines, use less energy and give off fewer pollutants. Imagine, for example, if today's electric car battery - now about the size of a college-dorm refrigerator - could be reduced so that it resembled a flashlight battery. Also, consider what miniaturization could mean to the airline industry, where even a one-cent increase in fuel prices means additional costs of nearly $200 million annually.

Second, the advances in nanotechnology research - particularly the solutions to the gold problem - mean that nanotechnology is much closer to product commercialization than previously. The progress that's taken place should lead fairly quickly to nanotechnology's "Holy Grail": the industrialization of production at the nanoscale. The days of nano-assembly that took place one molecule after another should soon be behind us.

Third, progress in nanotechnology could lead to the next great advance in medical diagnostics and treatment. For example, according to the journal Nature Nanotechnology, IBM scientists have developed a new technique for printing nanoparticles.

Unlike conventional micro-fabrication techniques, which cut nanoparticles from larger pieces of material, the printing process precisely and efficiently places nanoparticles on a surface. This could lead to printing arrays of nanoparticles that can detect particular cells in the body. As a result, doctors will be able to quickly scan patients for cancer cells.

Fourth, the miniaturization provided by nanotechnology is part of a worldwide effort, but it's particularly strong in the U.S. The American economy is in a never-ending race to use scientific and technical advances to generate wealth and create jobs. Nations in competition with us have major advantages in some areas. For example, Russia is putting some of its petrodollar profits to use in nanotech research, but those profits will be short-lived. Also, China enjoys a major cost advantage in labor, but the aging of China's workforce and its growing skills shortage will erase that advantage going forward.

To remain the world's most important economy, the U.S. must keep its leadership in advanced technology, especially nanotechnology. The technology may focus on what's "small," but the implications are of monumental importance.

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