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.
The next step for the research group is to start more extensive preclinical testing. They will be looking for a hormone, human chorionic gonadotropin (HCG), that can be considered a marker for cancer because it is produced by tumors but not normally found in healthy individuals (unless they are pregnant).
The researchers are now preparing a paper on the work and have presented their findings at recent meetings of the European Cancer Society and the American Institute of Chemical Engineers.