84 Nanomedicine but complete digestion and excretion of the bug’s remains can take an hour or longer. But the first thing a microbivore has to do is reliably acquire a pathogen to be digested. If the correct bacterium bumps into  the  nanorobot  surface,  reversible  binding  sites  on  the microbivore hull can recognize and weakly bind to the bacte- rium. A set of 9 different antigenic markers should be specific enough, since all 9 must register a positive binding event to confirm that a targeted microbe has been caught. There are 20,000  copies  of  these  9-marker  receptor  sets,  distributed in  275  disk-shaped  regions  across  the  microbivore  surface. Inside the receptor ring are more rotors to absorb glucose and oxygen from the bloodstream for nanorobot power. At the center of each receptor disk is a grapple silo; each disk is 150 nanometers in diameter. Once  a  bacterium  has  been  captured  by  the  reversible receptors, telescoping grapples rise up out of the microbivore surface and attach to the trapped bacterium. The microbi- vore grapples are modeled after a watertight manipulator arm originally designed by Drexler [17] for nanoscale manufactur- ing. This arm is about 100 nanometers long and has various rotating and telescoping joints that allow it to change its posi- tion, angle, and length. But the microbivore grapples need a greater reach and range of motion, so they are longer and more complex, with many additional joints. After rising out of its silo, a grapple arm can execute complex twisting motions, and adjacent grapple arms can physically reach each other, allowing them to hand off bound objects as small as a virus particle. Grapple handoff motions can transport a large rod- shaped bacterium from its original capture site forward into the mouth of the microbivore device. The bug is rotated into the proper orientation as it approaches the open mouth.