And then, partly by accident, team member Ji-Ho Park, a graduate student at UC San Diego, made an important discovery. He found that if he created a structure composed of several smaller iron oxide balls strung together like an earth worm and coated with what Sailor called "slime," it remained in the mice for up to 24 hours. It is not clear yet why that worked.
In addition, the researchers found that the nanoworms showed up in scans much more brilliantly than the balls if they were separated. In other words, the whole was brighter than the sum of its parts, suggesting it will be possible to see even much smaller tumors.
The "slime" that played such a critical role in this project really wasn't slime at all. It was actually a polymer coating with a tumor-targeting molecule, a peptide called F3, developed in the laboratory of Erkki Ruoslahti, a cell biologist at UC Santa Barbara and a member of the team. Because of the nanoworm's shape, many F3 molecules can be attached to it, thus increasing its ability to find tumors.
"We put a little fishing lure on these guys so they'll hook specifically onto the tumors," Sailor said.
That should make it possible for scientists to create nanoworms that will deliver drugs directly to tumors without killing nearby healthy cells, according to Sangeeta Bhatia of MIT, a physician who was part of the team.
That would give them a one-two punch — find the tumor and kill it.
And then, as Sailor emphasized, get the heck out.
"Our mantra is it has got to be non toxic, and it has to be brief, and it has to degrade into nontoxic products as well," he said. "In the end, you want everything to leave the body."
But this is scientific research, not a cure for cancer. It will take many years, and much refinement, for this kind of research to move from the lab to the medical ward.
Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.