Nanotechnology-based biomedical innovations are already in industrial production—with some nanoproducts already on the market. While nanotechnology may someday enhance implants and enable blind people to see, present-day concerns include the potential risks of nanomaterials and the government's role in the monitoring of this new technology.

The incredible potential of nanotechnology to improve health care and further medical research is being realized with much government support—receiving hundreds of millions of dollars in funding. In 2000, former President Bill Clinton declared the founding of the U.S. National Nanotechnology Initiative (NNI), and nanotech programs in Europe, Japan and other Asian countries have also received strong government backing. For the fiscal year 2002, NNI's budget is $604 million, including $40.8 million for the National Institutes of Health (NIH), and the proposed budget for FY 2003 is $710.2 million. Meanwhile, the European Commission will provide $180 million of support to nanotech research this year and between $270-315 million next year.

The three most promising biomedical applications for nanotechnology are diagnostics, drugs, and prostheses and implants. The first includes diagnostic sensors and "lab-on-a-chip" techniques—which can analyze blood and other samples and form part of analytical instruments for new drug development. The second application—drugs—includes delivery of medication to fight cancer, for implanted insulin pumps and gene therapy. The third application, meanwhile, involves the use of nanostructured materials for better prostheses and implants. While European public research funding and industry networking have emphasized applications that are expected to reach the market in 5-10 years, U.S. government funding has focused more on fundamental research. The U.S. has also aggressively sought ways to utilize nanotechnology to defend against biological and chemical warfare and terrorism, especially since the events of September 11.

Diagnostics
One such project is being sponsored by the Defense Advanced Research Projects Agency (DARPA). "This project is about a biosensor to identify bacteriological infections in biowarfare," says George Robillard, director of the Biological Materials and Devices (BIOMADE) research center, which is participating in the DARPA-funded endeavor and is part of the University of Groningen in The Netherlands. "The American army wants to integrate a wearable biosensor in clothing. A soldier should be able to see within 20 minutes if he has been in contact with anthrax." Other bacteria can also be detected. "Our technology is general, not specified for any one disease-causing agent," says Robillard. "What DARPA funds is fundamental research. We hope to have proof of principle in three years."

For other biomedical sensors, market entry is more imminent, says a recent U.K. Foresight report, which detailed the development and time-to-market of applications including those utilizing nanotechnology. According to the study, the following are already on the market or on the verge of their debut:

• sensors for medical and environmental evaluation and for the production of pure chemicals and pharmaceuticals

• tough, lightweight materials for defense, aerospace, automotive and medical applications

• lab-on-a-chip diagnostic methods

• sunscreens containing nanoparticles that absorb ultraviolet light

Meanwhile, the report says the following applications will enter the market in the next decade:

• medical implants that endure longer

• instant mapping of a person's entire genetic code

• the ability to prolong life by 50% from current life expectancies

Lab-on-a-chip systems are a promising research area because they can evaluate large quantities of compounds. In such a system, extremely small amounts of liquids or gases are combined in tiny channels, and the product of their reaction is analyzed. The Micro Electronics Material Engineering Sensors and Actuators (MESA+) institute at the University of Twente in The Netherlands is researching lab-on-a-chip systems and high-throughput screening (HTS), in particular. It is doing so for Amsterdam-based Avantium, an R&D company which hopes to come up with new methods and equipment for screening active compounds for pharmaceuticals and other products.

Drugs
Nanostructured materials are not being counted on to make new drug compounds but rather to deliver drugs to a targeted site in the body. Carbon buckyballs and nanotubes are so small they can move with ease inside the body. Their size makes them possible carriers of the active compound, which might be placed inside a nanotube or bonded to the surface of a particle. Other kinds of nanopowders or biomolecules are also potential drug delivery vehicles, and some have an even shorter time-to-market. One such system is ABI-007, which transports an established anticancer drug. It has already undergone an early human test, and the results were presented by the American Pharmaceutical Partners, Los Angeles, in April. ABI-007 is made up of a 130-nm-long protein-stabilized nanoparticle that delivers paclitaxel, a drug that targets breast, bladder and over a dozen other cancers. Such new systems depend on a drug-carrying artificial vector that can go into the body and move within it like a virus. ABI-007 will likely make its market entrance in a few years, if it passes more advanced clinical trials.

Prostheses and Implants
Nanotechnology could also help individuals who need new bones, teeth and other tissues. In The Netherlands, dentistry professor John Jansen of the Catholic University of Nijmegen is working on such tissue engineering applications from custom-made materials from MESA+. "We want to replace damaged or missing tissue by a similar equivalent material," he says. Nanotechnology offers two ways to accomplish this: through biological and biomimetic nanostructures. Methods using biological nanostructures, which Jansen says have the shorter time-to-market, involve placing a biological material in a mold, which makes it take the shape of a body part, such as a hipbone. Meanwhile, the biomimetic technique uses a predefined nanochemical structure (such as an array of molecules) or nanophysical structure (such as a tiny crystal) which act as seed molecules or crystals and allow the material to self-fabricate.

A third nanotechnology application is using nanostructured materials in artificial sensory organs such as an electronic eye, ear or nerve. This application and the biomimetic approach are many years away from development.

Dangers Ahead
The alleged risks that nanotechnology applications pose to human health and the environment are unsubstantiated because the technology is too new. However, potential dangers should be heeded because these nanoparticles could very well accumulate in the body. Previous experience with such unintended effects as drug resistance to antibiotics and the chemical DDT remaining in the environment urges us to err on the side of caution. Furthermore, viruses are nano objects and our history with viruses should encourage close monitoring of nanomaterials, says Debra Rolison of the Naval Research Laboratory, Washington, DC. In a European Commission-National Science Foundation workshop held early this year, participants came to the following conclusion: "Nanobiotechnology could dramatically improve public health, but there is concern that technological developments could cause unforeseen adverse effects. Studies are needed to determine what environmental and health risks are associated with nanomaterials."

On the Leading Edge…
Here's a brief look at some of the biomedical/pharmaceutical applications for nanotechnology being developed today:

• U.S. scientists are using fluorescent nanoparticles to look into the structure of a brain-mimicking gel to find out why it is such a good surrogate for living brain tissue during drug trials. http://www.nanotechweb.org/articles/news/1/8/3/1

• Many cosmetics made from nanoscale particles can already be purchased. One example is sunscreen composed of quantum dots, which are nontoxic and more stable than organic dyes.

• Pharmaceutical companies can now perform tests on biological samples quickly and cheaply with a new fabrication technique that makes the microchannels and chambers needed for such experiments. This new method called soft lithography—developed by a Harvard professor and collaborators—can shape nanosize structures in soft materials like rubber.
  http://www.sciam.com/article.cfm?articleID=00026AE5-7E2F-1D2B-97CA809EC588EEDF&pageNumber=1&catID=2

Sources: Biomedical Applications of Nanotechnology
Ineke Malsch
The Industrial Physicist, June/July 2002
http://www.aip.org/tip/INPHFA/vol-8/iss-3/p15.pdf

Nanoparticles Probe Brain-Mimicking Gel
Liz Kalaugher
Nanotechweb.org, August 5, 2002
http://www.nanotechweb.org/articles/news/1/8/3/1

Soft Manufacturing
Gary Stix
Scientific American, August 2002
http://www.sciam.com/article.cfm?articleID=00026AE5-7E2F-1D2B-97CA809EC588EEDF&pageNumber=1&catID=2