MIT researchers under Dr. Michael Cima in the Department of Materials Science and Engineering created a silicone device, containing a load of nanoparticles, designed for in vivo use, as a monitor of neoplastic growth and response to chemotherapy:
The new technique, known as implanted magnetic sensing, makes use of detection nanoparticles composed of iron oxide and coated with a sugar called dextran. Antibodies specific to the target molecules are attached to the surface of the particles. When the target molecules are present, they bind to the particles and cause them to clump together. That clumping can be detected by MRI (magnetic resonance imaging).
The nanoparticles are trapped inside the silicone device, which is sealed off by a porous membrane. The membrane allows molecules smaller than 30 nm to get in, but the detection particles are too big to get out.
The device can be engineered to test for many things at the same time, leading Kim to offer a turkey-based analogy.
“When you’re cooking a turkey, you can take the temperature with a thermometer,” she said. “But with something like this, instead of just taking the temperature, you can find out about the moisture, the saltiness, and whether there’s enough rosemary.”
In addition to monitoring the presence of chemotherapy drugs, the device could also be used to check whether a tumor is growing or shrinking, or whether it has spread to other locations, by sensing the amount and location of tumor markers.