© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

9.3.1.6 Metamorphic Manipulators

Metamorphic manipulators (Section 5.3.1.3) are fully reconfigurable manipulative or locomotive appendages that can be deployed from compact storage volumes. Surface area, contour, volume, length, and stiffness of the protuberance may be varied at ~KHz frequencies (Section 5.3.1.4). Metamorphic manipulators exuded from a nanorobot surface may temporarily assume many forms including arms/legs, hands/fingers, barriers and surrounds, grapples, bubbles, and a wide variety of geometric shapes, all under programmatic or stochastic control (Section 9.3.3).

Many examples of highly plastic protuberances are known in microbiology at many size scales, such as the pseudopods of fibroblasts and amoebas (an amoebic pseudopod can extend and engulf a 100-micron paramecium in ~10 sec,¹²⁵² applying a stress force¹⁴⁶² up to ~2900 N/m²), blebbing and microspikes,⁹³⁸ the ~40 nm import receptors (cytoplasmic filaments) ringing the mouth of the nuclear pore complex,¹²⁶⁴ cyclosis in giant green algae cells at velocities up to 100 microns/sec,⁹³⁸ and the flexible plasma membrane extensions that occur during amoeboid locomotion (Section 9.4.3.7). Human axons elongate at ~10 nm/sec.¹²⁴⁰

The green plastid tubules of chloroplasts in plant cells are yet another example. These tubular projections arise initially as protuberances from the chloroplast surface that elongate and extend. They are dynamic in the living cell, continuously changing their shape, moving around, shrinking back, and sometimes connecting with other chloroplasts. Their width ranges from 350-850 nm, with lengths up to 15 microns. Plastid protuberances may extend at a velocity of 10-100 nm/sec and encircle another body, much like a finger curling around a sphere.⁷³⁵

Metamorphic manipulators are expected to present significant, though probably not insurmountable, design challenges.

Last updated on 20 February 2003