Johns Hopkins researchers have invented dust-particle-size devices that can be used to grab and remove living cells from hard-to-reach places without the need for electrical wires, tubes, or batteries. Instead, the devices are actuated by thermal or biochemical signals. The mass-producible microgrippers each measure approximately one-tenth of a millimeter in diameter. In lab tests, they have been used to perform a biopsy-like procedure on animal tissue placed at the end of a narrow tube. According David H. Gracias, supervisor of the project, these micro-tools could help doctors diagnose illnesses and administer treatment in a more efficient, less invasive way.
Today, doctors who wish to collect cells or manipulate a bit of tissue inside a patient's body often use tethered microgrippers connected to thin wires or tubes. But these tethers can make it difficult to navigate the tool through hard-to-reach locations. To eliminate this problem, the untethered grippers devised by Gracias' team contain gold-plated nickel, allowing them to be steered by magnets outside the body. The microgripper design has six three-jointed digits extended from a central "palm" and resembles a crab. The gold-plated nickel in the palm and digits will allow doctors to see and guide the grippers with medical imaging units such as an MRI or CT.
