By Bill Clayton

In 1997, neurologists determined that a portion of a young man's brain no larger than a fingernail was causing him to have seizures, sometimes as many as 18 a day. The defect lay in the occipital lobe, buried in the vision center. Neurologists tried medication and specialized stimulation of cells that sometimes prevents seizures. Nothing helped. Surgery seemed to be the only solution. But to remove the diseased tissue, surgeons would have needed to cut through the healthy tissue that governs sight. Ironically, the surgery that might have eliminated the seizures would also have created scar tissue that left the man blind. Faced with the dilemma, he chose to keep his sight and continue having seizures.

Someday, perhaps in the not too distant future, surgeons will be able to treat this condition by using a nanotube with a diameter 1/10,000 the diameter of a human hair to travel between healthy brain cells and repair those that are damaged -- without creating scar tissue.

The study of nanotubes is just one of many ongoing Michigan Engineering investigations into nanotechnology. In fact, there are far too many other noteworthy projects to mention in this limited space. So, this article briefly describes a selection of other current investigations into nanotechnology, all of which have the objective of helping to improve people's lives in the areas of healthcare, the environment, energy, homeland security and manufacturing, to name just a few.

Healthcare

Laser Illumination of Nanoparticles for Low-Energy Detection

Biomedical Engineering Chair Matt O'Donnell, the Jerry W. and Carol L. Levin Professor of Engineering, and professor, Electrical Engineering and Computer Science, is examining the difficulties that conventional imaging systems have in detecting the very low energies associated with molecular interactions, which are indicators of cellular function and dysfunction. To overcome this problem with

Nanoparticles make these cells highly visible to conventional imaging technologies.

commonly used systems such as magnetic resonance imaging and ultrasound, O'Donnell and his interdisciplinary team are using a laser to transform a nanoscale object into a microscale object within a cell in such a way that the object becomes highly visible to conventional imaging technologies. Once investigators are able to "see" objects of this sort, they can target and treat only those cells that are diseased, and avoid damaging healthy cells.

O'Donnell said that such molecular imaging "has the potential to transform medical practice by noninvasively sensing nanoscale molecular events in the body. For practical applications, the trick is to amplify molecular events so conventional systems such as ultrasound and MRI can image nanoscale processes."

Smart Drugs and Smart Surfaces

James Baker, the Ruth Dow Doan Professor of Biologic Nanotechnology, professor, Biomedical Engineering and Internal Medicine, and his interdisciplinary research team are looking into the use of nano- technologies to find and enter specific cells to deliver medications. Baker's work is varied, but this program is another demonstration of the ways in which nanotechnology can improve healthcare.

This particular program is important because it addresses problems in the administration of powerful medications that, in coursing through the entire body, can be damaging as well as therapeutic.

Nanoparticles, seen here joined by strands of DNA, can be programmed to identify and deliver medication to specific cells.

Chemotherapeutic drugs, for example, have an indiscriminate nature that can be devastating -- the medication attacks cancerous cells but destroys healthy tissue as well. The side effects aren't the same for all people but, in general, they include nausea and vomiting, hair loss, fatigue and anemia, mouth sores, diarrhea, menopause and suppression of the immune system, which increases the risk of infection. Some patients say the treatment is as bad as the disease.

To help alleviate that problem, Baker's team is building and programming nanoparticles that can find and enter specific cells to deliver lethal doses of chemotherapeutics precisely where they're needed. They'd leave normal cells unharmed and even report back on their success in attacking the cancer.

Smart surfaces respond to various substances, attracting or repelling them according to preprogrammed instructions.

Joerg Lahann, assistant professor, Chemical Engineering, Materials Science and Engineering, and Biomedical Engineering, is approaching the problem in a slightly different manner, using nanotechnology to create "smart surfaces" that have the ability to "respond" to external stimuli. Lahann and his team of researchers program the surfaces of nanoparticles to selectively attract or repel various substances. This makes the particles useful in tailoring drug delivery to specific cells. Only one-billionth of a meter thick, a smart surface can also be useful in coating biomedical implants, and in microfluidic systems, DNA microarrays and tissue engineering.

Read more about smart drugs at http://www.umich.edu/news/index.html?Releases/2004/Mar04/r032304.

Quantum Dots for Medical Imaging

Quantum dots are nanocrystals that, when illuminated with ultraviolet light, emit a vast spectrum of colors that researchers can use to locate cells and identify their biological activities. These crystals offer optical detection far more effective than conventional dyes used in many biological tests with technologies such as magnetic resonance imaging, one of today's most powerful imaging technologies.

Using ultraviolet light to illuminate quantum dots, such as the one seen here, researchers can locate specific, individual cells and identify their biological activities.

Nick Kotov, associate professor, Chemical Engineering, Biomedical Engineering, and Materials Science and Engineering, leads a team that's developing quantum-dot imaging to locate and identify cells and biological activities. The technology will accelerate not only the development of imaging technologies for medical diagnostics but also the creation of new pharmaceuticals, a process that requires precise identification of chemicals and their interactions. Quantum dots might someday help doctors detect cancer cells earlier than is possible with current techniques -- a big step in improving people's lives.

Environment

Nanoscale Systems for the Removal of Heavy Metal Ions from Groundwater

Current methods for cleaning up contaminated soil and groundwater at thousands of industrial sites are generally regarded as expensive and slow -- the process can sometimes take decades. Kim Hayes, professor, Civil and Environmental Engineering, Program Director of Environmental and Water Resources Engineering, leads a research team that's using nanotechnology to develop inexpensive reduced iron nanoparticles that work more efficiently than conventional methods to remove a range of toxic

By introducing preprogrammed iron nanoparticles into groundwater, researchers can reduce toxic metals, such as arsenic and cadmium, into benign substances.

metals, such as arsenic and cadmium, from groundwater. The efficiency results from the ability of the particles to work on all of these contaminants simultaneously to complete a clean-up. In addition, because the particles are so miniscule, researchers can inject them into places that larger particles can't reach.

Hayes said that his team makes common materials such as sand "highly reactive by producing nanoscale composite coatings of iron and sulfide. We anticipate a pilot-scale demonstration of these systems at a contaminated Department of Defense site when we complete this three-year project."

It's likely that variations of this process will have similar applications in removing toxic metals from lakes, rivers or streams. Hayes believes that nanoparticles they're creating might even be effective, someday, in removing toxic metals from nuclear waste sites.

Energy

Layer-By-Layer Assembly for Solar Cells and Fuel Cells

Nano-films have properties that lend themselves to a variety of applications, including the improvement of solar cells and fuel cells, and the construction of body armor, aviation equipment and artificial bone.

Disruptions in oil supplies, environmental pressures, the threat of terrorism -- these and other modern problems have made energy an issue of increasing importance. But, here too, nanotechnology is proving to be a major problem-solving force. Associate Professor Kotov's team has developed a unique method for creating nano-films that are semi-conductive, metallic or magnetic. These films are just several nanometers thick and, depending on how researchers assemble them, have properties that lend themselves to a variety of applications, one of which is the development of more efficient solar cells and fuel cells.

In addition to the positive effects that nano-films will have in the energy field, they're also proving useful in creating high-tech body armor, aviation equipment and artificial bone.

Read about the characteristics of layer-by-layer materials at http://www.engin.umich.edu/dept/cheme/people/kotovres.html.

Homeland Security

Nanocomposites to Combat Chemical and Biological Terrorism

The events of September 11, 2001, spawned numerous Michigan Engineering research programs that are focused on using nanotechnology to improve homeland security. A multidisciplinary team of

Preprogrammed dendrimer nanoparticles can dismantle harmful chemical and biological agents, transforming them into benign substances.

investigators is developing a fluid which looks as unremarkable as hand cream or skim milk, is safe enough to rub on skin, but contains dendrimer nanoparticles that can tear apart the cells of infectious agents such as viruses, bacteria and yeast. (A dendrimer is a polymer in which arrangements of atoms on branches connect to a central backbone of carbon atoms.) In one modification of dendrimer nanocomposites, researchers customized a material so that it resembled the immune system, giving the material the ability to inactivate substances that are chemically harmful or pathogenic. That same nanocomposite, applied topically to the skin, was able to act as a therapeutic agent -- it could save the lives of those who've already contacted a harmful substance.

Read more about nanoemulsions at http://nano.med.umich.edu.

Manufacturing

Self-assembly of Nanoparticles

Sharon Glotzer, an associate professor in the departments of Chemical Engineering, and Materials Science and Engineering, leads a group of researchers who are

"Sticky patches" enable nanoparticles to adhere to each other and self-assemble into organized groupings with predetermined shapes.

using computer simulation to model nanoparticles that assemble themselves into wires, sheets, shells and other structures for specific purposes. The Glotzer groupÕs development of Òsticky patchesÓ enables nanoparticles to adhere to each other at just the right places to form organized groupings with predetermined shapes. The ability of nanoparticles to self-assemble could someday enable researchers to program these tiny bits of matter to put themselves together to create nanomaterials and nanodevices such as nanoscale pumps, computers and even mechanisms that can sense and respond to external stimuli to detect harmful agents.

Glotzer said that nanoparticles will be "building blocks -- the 'atoms' and 'molecules' of tomorrow's materials, self-assembling into novel structures made possible solely by their unique design. Our computer models provide design rules for making building blocks. Our results predict what works and what doesn't for assembling a particular shape from the bottom-up."

Read more about self-assembling nanoparticles at http://www.sciencedaily.com/releases/2004/08/040819082902.htm.

Space Technology and Transportation

There's much that nanotechnology will do to improve space research and transportation. One program that has attracted particular attention from NASA is Michigan Engineering's research into the use

Researchers use novel fiber-optic probes, such as the one seen here, to collect light emitted by nanoparticles that have been introduced into the bloodstream. Investigators glean information from the collected light to monitor cells for radiation exposure.

of nanoparticles to monitor the amount of radiation that astronauts encounter -- one of the leading health risks in long-term space travel.

Professor Baker's multidisciplinary team is combining nanoparticles and an ultrafast pulsed laser to detect individual cells that have been damaged by radiation exposure. A certain amount of cell death is normal and expected after exposure. What the researchers are looking for is a sudden increase in the population of dead white blood cells, which is one of the calling cards of radiation poisoning.

Baker said that this technology "will allow the monitoring of astronauts in space as if they're in a hospital bed on earth. It will markedly improve the safety and success of interplanetary space flight."

Read more about monitoring radiation exposure during space travel online at http://tinyurl.com/48zkd.

In the area of transportation, Johannes Schwank, a professor in the department of Chemical Engineering, is leading an investigation into the development of novel thin films to improve the performance of devices that are critical to catalytic converters. Similar films will also have applications in the pharmaceutical industry and in the transformation of hydrocarbons for fuel cells.

Top view of gas sensor, consisting of an active sensing film (center), about 10 nanometers thick, on a supporting membrane about 100 micrometers thick.

By its very nature, nanotechnology is a multidisciplinary field, drawing on resources from engineering, physics, chemistry, biology and many other sciences. It offers far-reaching possibilities and, realizing nanotechnology's potential, Michigan Engineering has made it an integral component in the College's commitment to engineering that improves people's lives. -E