Denis Wirtz switches on his magnetic tweezers, grabs hold of a single DNA molecule and uses a joystick to steer it carefully through a solution. Wirtz, an assistant professor of chemical engineering at The Johns Hopkins University, is not playing an electronic game. He is manipulating molecules in ground-breaking research that could lead to new surgical tools and drug delivery systems. Using Wirtz's device, a physician may soon magnetically move a microscopic sac filled with cancer-killing medicine through a patient's veins, then empty it directly into diseased cells.
"You could use these magnetic tweezers to transport a vesicle or fluid-filled cell containing a drug," Wirtz explains. "You could use the tweezers as sort of a surgical tool to take it to the targeted area and then penetrate the diseased cells. It could be done very easily. Right now, you can move things inside a vein mechanically, but it's very invasive. With magnetic force, it's non-invasive."
Wirtz, who invented the device three years ago as a postdoctoral student in Europe, is reconstructing it in a new lab at Hopkins. Here, he hopes to turn the magnetic surgery idea into reality. He has attracted more than $500,000 in federal and private grants to continue studying and refining the tool.
The forces that allow Wirtz's device to work are already familiar
to any child who has played with a magnet. If you place a sheet
of paper over a steel button, then hold the magnet on top of the
paper, you can move the button without touching it. Wirtz's
magnets are three sets of coiled copper wire, each connected to a
power source. The coils are positioned to produce electromagnetic
fields in three dimensions: backward and forward, side to side,
and up and down. With a joystick, Wirtz can shift the amount of
electricity flowing to each set of coils. That lets him move a
magnetic object in any directi
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Contact: Phil Sneiderman
prs@resource.ca.jhu.edu
410-516-7160
Johns Hopkins University
10-Jan-1997