Nanomedicine, Volume IIA: Biocompatibility

© 2003 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume IIA: Biocompatibility, Landes Bioscience, Georgetown, TX, 2003


15.6.4 Technological Intrusiveness

The intrusion of nanodevices into the human body can displace both volume and function of our natural biological systems. The consequences of such displacement remain incompletely defined. For example, augmentative nanorobotic systems may establish new equilibrium levels and possibly create new failure modes or instabilities in natural homeostatic processes (Chapter 17). The microbial ecology may react in a number of ways to omnipresent medical nanorobots with whom it has not co-evolved, with the possible emergence of novel pathogenic species displaying unexpected behaviors and abilities (Chapter 17). Specific control protocols are needed to ensure appropriate responses (e.g., when a nanodevice unexpectedly exits the body by being bled out) in various common medical situations (Chapter 12).

Because self-replicating devices [35] might be the most technologically intrusive class of nanorobot, it cannot be emphasized too strongly that mechanical medical nanodevices should not be allowed to self-replicate inside the human body (Section 2.4.2), nor should they have any need for self-replication themselves (Section 1.3.3). Machines that perform medical tasks are fundamentally different from machines that manufacture other machines. Self-replicating systems [35] may be the key to low cost manufacturing but there is no need to allow such systems to function in the outside world. In an artificial and controlled environment these factory systems will manufacture simpler and more rugged applications products which are then transferred to the end user. Medical devices designed to operate in the human body should not self-replicate: such devices can be manufactured in a controlled environment, then injected or implanted into the patient as required. The resulting medical device will be simpler, smaller, more efficient and more precisely designed for the task at hand than a device designed to perform the same function and self-replicate [9]. Given the potential for accident and abuse [7, 8, 21], artificial replicators will almost certainly be very tightly regulated by governments everywhere. It is unlikely that the FDA (or its future or overseas equivalent) would ever approve for general use a nonbiological medical nanodevice that was capable of in vivo replication, evolution, or mutation. Guidelines to avoid accidents and foreseeable abuses have been promulgated for biotechnology replicators [38] and have been proposed for nanotechnology replicators [39].

It is also unlikely, and unnecessary, for individual medical nanorobots each to possess a human-level or even near-human artificial intelligence. Many medical nanorobots will have very simple computers aboard each device. For artificial nanorobotic red cells (respirocytes [3573]), a ~103 operations/sec computer may suffice far less computing power than an old Apple II machine – while nanorobotic white cells (microbivores [2762]) may need only ~106 ops/sec of onboard capacity. Still more sophisticated cellular repair nanorobots should demand no more than 106-109 operations/sec of onboard computing capacity to do their work. This is a full 4-9 orders of magnitude below even the potential for true human-equivalent computing which is conservatively estimated as 10-1000 teraflops (~1013-1015 operations/sec) [40-42]. Faster computing capacity is simply not required for individual medical nanorobots. The potential for unexpected emergent behaviors (as suggested in both the scientific [43-47] and science fiction [48-50] literature) among large in vivo populations of small-capacity fixed-program individual nanodevices seems low but should be investigated further.


Last updated on 30 April 2004