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Feb. 4, 2004 — Nuclear engineer Michael Kaminski and neurologist Axel Rosengart are the first to admit their system for detoxifying contaminated blood is still getting its legs. Yet they expect it will be not only a front-runner for treating soldiers or civilians exposed to threats such as anthrax, but it may even be a triple-crown winner.
Kaminski, a researcher in the chemical engineering division at Argonne National Laboratory in suburban Chicago, and Rosengart, an assistant professor in neurology and neurosurgery at the University of Chicago, are developing a magnetic nanoparticle-based technology that removes biological, radiological and in some cases chemical toxins from blood.
Their goal is to devise a portable system that is fast and thorough using magnetic nanoparticles coated with antibodies or chemicals that complement toxins. Once injected into the patient, the particles latch onto toxins and are later removed when the blood is pumped through tubing into a magnetic separator. Cleansed blood is then returned into the body. The approach is particularly safe because the closed loop system never exposes blood to the outside environment.
“We want (the particles) in the body for a time to circulate in the blood,” Rosengart said. No matter what the means of exposure, the transport of any toxin is through the circulatory system, he said. If the toxins can be removed before they accumulate in tissue, then organs won’t fail and the patient will survive.
“With nerve gas, it can take minutes” between exposure and death, Rosengart said. But some chemical and many biological and radiological agents need hours or even days to cause fatal damage, a wide enough window for the particle treatment to be effective.
Rosengart and Kaminski began collaborating years ago on magnetic nanoparticle-based drug delivery treatments for conditions such as brain tumors. The particles could penetrate the blood-brain barrier that often blocks larger therapeutic molecules. Using magnetic forces, doctors could then guide the drugs to targeted brain tissue.
The team decided to expand their work to include treatments for hazards after the Sept. 11 terrorist attacks in 2001. They received funding through the Defense Advanced Research Projects Agency to test their ideas. Agencies as diverse as the National Institutes of Health and the FBI have shown interest in the procedure.
But they still face numerous challenges, they said. The particles, which start with magnetic cores in the eight to 12 nanometer range, must be the right size to navigate within the body. If they’re too small, they may pass out the kidneys; and if they’re too large they may get trapped.
The particles also need to be biocompatible so the body accepts them and biodegradable in case some remain after treatment. “We’re getting the particles so they can evade the immune system for a long enough time,” Kaminski said. “I don’t see this technology being deployed in the next couple of years.”
Their use of Food and Drug Administration-approved antibodies, reagents and off-the-shelf medical components could remove some regulatory speed bumps. That could pave the way for not only military and civilian defense applications but clinical treatments such as overdoses, Rosengart said.
Some companies already use magnetic nanoparticles in medical applications. Biophan Technologies Inc. in Rochester, N.Y., reported in 2003 that a magnetic nanoparticle coating applied to catheters and other devices improved imaging of the implants during magnetic resonance imaging procedures.