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. Nano World: Nanomagnet future bright
NEW YORK, (UPI) May 12, 2005
Nanomagnets have not received nearly the industry attention that nanoelectronics or nanobiotechnology have, but their potential makes them very attractive.

The global market for nanomagnetic devices and materials totaled roughly $4.3 billion in 2004, and could reach nearly $12 billion in 2009.

"What's amazing about nanomagnetics is that applications of the technology run the gamut from literally decades-old products, such as magnetic fluids used for industrial sealing applications, to futuristic high-tech uses that are likely years from commercialization, such as agents for killing tumor cells," said Mindy Rittner, a scientific adviser in the Chicago office of intellectual property law firm Brinks Hofer Gilson & Lione.

"There's a lot of potential," Rittner told UPI's Nano World.

Conventional magnets act like collections of tiny bar magnets that line up into spirals, due to what scientists call magnetostatic interaction. That means the magnetic poles in a conventional magnet end up pointing in all directions. At the distance of about 10 nanometers or less, however, the esoterically named quantum mechanical exchange interaction dominates, so each tiny bar magnet lines up in rows. The magnetic poles in nanomagnets end up pointing in the same direction, explained physicist Denis Koltsov at Lancaster University in Britain.

The fact nanomagnets can have their magnetic poles all point the same way helps make hard disks possible. Data is symbolized in computers as ones and zeroes, and hard drives represent these by aligning magnetic nanocrystalline grains to point either one direction or the other.

Moreover, the devices used to store and retrieve data from hard disks are nanomagnet-based themselves, employing stacks of nanoscale magnetic films. Data storage applications count for more than 90 percent of today's nanomagnet market, roughly $4 billion in 2004, Rittner wrote in a report in Nanotechnology Law & Business Journal, which she penned while director of nanotechnology research at market analyst firm Business Communications Company in Norwalk, Conn.

As new applications grow with hard disk use and the emergence of magnetic RAM, data storage should continue to dominate the nanomagnet market at nearly $11.5 billion in 2009, the BCC report added. Unlike the most common types of RAM used today, which require a continuous supply of electricity, MRAM chips store data using nanomagnets, such that information remains even when the chips are not powered.

Nearly 20 firms are active with MRAM, and industry research firm NanoMarkets, in Sterling, Va., told Nano World the market for MRAM should grow to $2.1 billion by 2008 and $16.1 billion by 2012.

In comparison, biotechnology and industrial products make up less than 10 percent of the nanomagnet market. Still, they currently account for hundred-million-dollar markets, and BCC expects both sectors to experience double-digit growth in the next five years.

"If we have cancer or any other serious condition, one would easily trade gigabits of MP3s for a treatment that works or for any improvement in the quality of life. The shift to biomedical applications is therefore anticipated," Koltsov told Nano World.

Biotechnology applications, which commanded roughly $158 million in revenues in 2004, are projected to reach $310 million in 2009.

"Nanoscale objects can permeate biostructures. For example, you can inject suspensions of magnetic nanoparticles into a bloodstream, and have them go through without clogging up vessels. Depending on their size, they can even diffuse through the walls of the vessels as well," Koltsov said.

Magnetic nanoparticles regularly find use in magnetic resonance imaging medical scans. When injected or taken orally, they help enhance imaging of tissues and organs. Varying the nanoparticle size affects which organs and tissues the nanoparticles migrate to. Scientists at Harvard University also have customized the surface of magnetic nanoparticles with antibodies that bind to viruses, creating a virus-detecting MRI scan that works much faster than conventional virus detection techniques.

Below a certain size, magnetic nanoparticles becomes superparamagnetic, which means they do not act like magnets unless they are in a magnetic field.

"Superparamagnetic nanoparticles are useful, for example, in bioseparations applications," Rittner said.

When given special coatings, they latch onto targets, such as cells, parasites or DNA, and then magnetic fields help pull the nanocrystals and their bound targets out. The ability to rapidly pull out a target of interest potentially also has use in biosensors that seek out germs.

Doctors could guide drug-laced magnetic nanobeads from outside a patient's body using magnetic fields until they reach their intended target, Koltsov noted. This would allow physicians to actively steer medicines exactly where they want them to go, limiting the amount of healthy tissue exposed to the drug. Several universities in the United States and Britain are involved in this research, he added.

Magnetic nanoparticles could by themselves help burn away cancer, Rittner added. Scientists in Denmark, Japan, Germany and the United States are developing a technique in which magnetic nanoparticles injected into malignant tissues later absorb energy from an external alternating magnetic field. Only diseased cells would die because some cancers are more susceptible to heat than normal cells.

The magnetic properties of nanocrystalline iron alloys are ideal for power transformer cores and other high-frequency industrial applications. Stacks of nanoscale magnetic films also can serve in highly sensitive, low-power magnetic sensors in a variety of industrial, automotive and biotechnology applications. BCC forecasted the industrial products sector should grow from roughly $93 million in 2004 to $167 million in 2009.

More than 80 companies are developing and using nanomagnetics-linked products and technology, Rittner noted. The countries that are home to most nanomagnetics companies are the United States and Japan, which respectively account for about 37 percent and 25 percent of the firms. Germany comes in at roughly 16 percent, with Britain and France tying at 6 percent each. Other nanomagnetics firms can be found in the Netherlands, Switzerland, Norway, China and Taiwan.

"Companies have recognized that nanomagnetics technology is enabling for various products and devices, and they're trying to capitalize on that. There's no question that this field will grow," Rittner said.

Nano World is a weekly series examining the exploding field of nanotechnology, by Charles Choi, who covers research and technology for UPI Science News. E-mail: sciencemail@upi.com

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