Physicians have tried to access the mammary ducts through the nipple in the past, injecting fluid solutions to try to wash out cells that could be examined and used for a diagnosis of cancer. However, this approach could only reach the first third of the breast due to fluid pressure from the ducts, which branch and become smaller and smaller as they approach the glands that produce milk, Leary said.
"The idea is that nanoparticles with a magnetic core can float through the naturally occurring fluid in the ducts and be pulled by a magnet as opposed to being pushed with pressure," he said. "We think they could reach all the way to the back of the ducts, where it is believed most breast cancers originate. Of course, we are only at the earliest stages and many tests need to be done."
Such tests could not be done using standard models that grow cells across a flat surface in a plastic dish, so the team created the artificial organlike model in which living cells line a three-dimensional replica of the smallest portions of the mammary ducts.
Leary is internationally known for his nanofabrication work using photolithography to build tiny, precise structures on thin pieces of silicon to create high-speed cell sorting and analysis tools. He used the same techniques to build a mold of branching channels out of a rubberlike material called polydimethylsiloxane. The channels are about 5 millimeters long of various diameters from 20 microns to 100 microns, roughly the diameter of a human hair, that match what is found near the end of the mammary duct system.
|Contact: Elizabeth K. Gardner|