Tiny tools can gather cells in narrow areas of the body for diagnoses This image shows a mu-gripper near the opening of an endoscopic catheter. Credit: Evin Gultepe, Gracias Lab, Johns Hopkins University BALTIMORE, April 24 (UPI) -- Tools as small as a dust speck, can perform biopsies in narrow conduits in the body to find signs of cancer or other diseases, U.S. researchers say. 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.