For some time now, scientists as well as science fiction writers have dreamed of nanotechnologies as an addition to the medical toolbox for helping patients to heal. New research published in Advanced Functional Materials provides some of the groundwork necessary to one day develop mini-robots that could perform delicate tasks inside your body. As the thinking goes, these nanotechnologies would be able to swim in your bloodstream and even assemble medical devices inside your body.

"We need to make things smaller to get inside the body easier, but if they are too small, they are not really useful," Dr. Metin Sitti of Carnegie Mellon University in Pittsburgh told New Scientist. "You want to assemble the robot inside the body." In essence, he is hoping to create a nano-doctor.

Using rods made of magnetic materials, Sitti and Dr. Eric Diller, also of Carnegie Mellon University’s Nanorobotics Laboratory, have created a simple version of micro-robots. Each is about one millimeter in length with two gripping arms. To manipulate the robots, a human doctor would employ the forces of a magnetic field enabling movement of the robots and operation of the grippers. So far, experiments have demonstrated that the nanorobots are capable of transporting small objects and building bridges from rods. Sitti told New Scientist he hopes future versions could be injected into the blood, along with parts for micro-machines, and then they would swim to a wound. There, the nanorobot would build a medical device while floating within the bloodstream.

Since 2001, Food and Drug Administration-approved pill cameras have been in use, but, comparatively speaking, they are rudimentary. Though they perform imaging tasks, they lack their own propulsion system, and so, move through the body naturally without a doctor's guidance. For this reason, Sitti continues to work on a new capsule that would possess greater capabilities than all previous versions. His therapeutic capsule endocscope has two magnets on either end, allowing a doctor to manipulate it from outside the body. It would also be possible, then, to twist and spin the nanorobot-capsule inside the patient. Because it is made out of a flexible elastomer, a doctor would even be able to change its shape. By placing a drug within a chamber at the center of the capsule, a doctor might inject a medicine to a specific site simply by changing the capsule's form. "Once reliable control is obtained, to increase the capabilities of the device, the capsule can be equipped with tools for performing tissue biopsy or for cleaning or cauterizing wound sites," wrote the authors in the description appearing on the NanoRobotics Lab website.

Source: Diller E, Sitti M. Three‐Dimensional Programmable Assembly by Untethered Magnetic Robotic Micro‐Grippers. Advanced Functional Materials. 2014.