Ā© Copyright 2000-2002, Robert A. Freitas Jr.
All rights reserved.
The vasculocyte, intended for use in the limited vascular repair of primarily intimal arteriosclerotic lesions, is a squat, hexagonal-shapedĀ nanorobotĀ with rounded corners, measuring 2.7 microns across and 1 micron talldesigned byĀ Robert A. Freitas Jr. Its 400-billion atom structure weighs about 8 picograms. The device is scaled so that its longestĀ cross-body diagonalĀ is shorter than 4 microns, the diameter of the narrowestĀ capillaries in the human body. The slightly-curved topmost surface is almost completely tiled with 174,000Ā molecular sorting rotorsĀ to allow rapid exchange of specific molecules between the interior of theĀ nanorobotĀ and the patient’s bloodstream.
On its six side walls the vasculocyte is enveloped by an extensibleĀ “bumper”Ā surface which cycles between 100 nm and 300 nm of thickness as internally-stored piston-pumpedĀ ballastĀ waterĀ inflates and deflates the surfaceĀ about once every second. This cycling allows aĀ nanorobotĀ situated on an arterial wall to continuously adjust its girth by up to 15% to match the regularĀ distensions of arterial wallĀ circumference that occur during each systolic pulse of the heart. On its bottom face, the vasculocyte has 625 stubbyĀ telescoping appendages, each capable of 1 cm/sec movements. Limbs are 30 nm in diameter and 100 nm long, spaced out along a regular grid about 100 nm apart to avoid any possibility of collision. Only 10% of them are used at any one time, to preserve 10-fold redundancy. Each leg walks on aĀ “footpad”Ā tool tip that is 10 nm in diameter. Acting like a snowshoe, the footpad distributes leg motion forces widely enough to avoid disruptingĀ cell membranes.
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