Engineers at Johns Hopkins University say the tiny tools require no batteries, wires or tethers and have been successfully used in animal testing to seize internal tissue samples.
The star-shaped devices, called mu-grippers -- incorporating the Greek letter that represents the term for "micro" -- don't need a power source because they are autonomously activated by body heat, which causes their tiny "fingers" to close on clusters of cells, a university release said Wednesday.
Because the tools contain a magnetic material, they can be retrieved through an existing body opening via a magnetic catheter, the researchers said.
In tests, the mu-grippers were used to collect cells from the colon and esophagus of a pig, selected because its intestinal tract is similar to that of humans.
"This is the first time that anyone has used a sub-millimeter-sized device -- the size of a dust particle -- to conduct a biopsy in a live animal," chemical and biomolecular engineering Professor David Gracias said. "That's a significant accomplishment. And because we can send the grippers in through natural orifices, it is an important advance in minimally invasive treatment and a step toward the ultimate goal of making surgical procedures non-invasive."