The researchers demonstrated that very small human melanoma tumors growing in mice--indiscernible from the surrounding tissue by direct MRI scan--could be "lit up" and easily located as soon as 30 minutes after the mice were injected with the nanoparticles.

Because nanoparticles can be engineered to carry a variety of substances, they also may be able to deliver cancer-fighting drugs to malignant tumors as effectively as they carry the imaging materials that spotlight cancerous growth.

"One of the best advantages of the particles is that we designed them to detect tumors using the same MRI equipment that is in standard use for heart or brain scans," says senior author Gregory Lanza, M.D., Ph.D., associate professor of medicine. "We believe the technology is very close to being useful in a hospital setting."

Lanza and his colleague Samuel Wickline, M.D., professor of medicine, are co-inventors of this nanoparticle technology. The effectiveness of the nanoparticles in diagnosis and therapy in humans will be tested in clinical trials in about one and a half to two years.

The spherical nanoparticles are a few thousand times smaller than the dot above this "i," yet each can carry about 100,000 molecules of the metal used to provide contrast in MRI images. This creates a high density of contrast agent, and when the particles bind to a specific area, that site glows brightly in MRI scans.

In this study, MRI scans picked up tumors that were only a couple of millimeters (about one twenty-fifth of an inch) wide.

Small, rapidly growing tumors cause growth of new blood vessels, which feed the tumors. To get the particles to bind to tumors, the researchers equipped them with tiny "hooks" that link o
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Contact: Jim Dryden
jdryden@wustl.edu
314-286-0110
Washington University School of Medicine
22-Apr-2005