| LE Magazine October
2000
REVIEW
 A Gift
From The Future
A review of Nanomedicine,
Volume 1: Basic Capabilities, by Robert A. Freitas
Jr.
Nanomedicine is an endlessly impressive and
uniquely important book. Like Newton’s Principia and Drexler’s
Nanosystems, it
stands as a marker between all that has come
before, and all that will come in the future. For
it is effectively a blueprint for the
future—essentially the whole future—of health,
longevity and medicine. It is not quite a
prediction—predictions are notoriously
difficult—but is instead an engineering sketch of
what will be possible for medicine based on the
laws of physics and chemistry, when humankind can
do everything consistent with those laws of
physics. Despite its focus on the ultimate future
of medicine, Nanomedicine is relevant
to nearly everyone alive today and now, in many
ways. It may save many lives, and it will
certainly elevate many more. It is, in a sense, a
gift from the future to those of us living in the
present.
The book is
at once very easy and very difficult to explain
and to understand. It is excellently written and
presented, and is about elemental themes of life
and the conquest of death, disease, discomfort and
ultimately even displeasure, at the hands of
technology. But no mere simple statement can
convey the staggering depth of the book, the
awesome scholarship that has produced it, and the
relentlessness with which Freitas has pursued his
subject. If you want the full story, you’ll have
to read the book.
To
start at the beginning, Nanomedicine is about
just that: nanomedicine. Freitas defines
nanomedicine at least twice. On page two, he says
“Nanomedicine may be broadly defined as the
comprehensive monitoring, control, construction,
repair, defense and improvement of all human
biological systems, working from the molecular
level, using engineered nanodevices and
nanostructures.” Later, he gives “the broadest
possible conception of nanomedicine” as “the
science and technology of diagnosing, treating and
preventing disease and traumatic injury, of
relieving pain, and of preserving and improving
human health, using molecular tools and molecular
knowledge of the human body.” Stated differently,
he notes, on page 17, that what is coming is “a
molecular technologic medicine in which the
molecular basis of life, by then well-known, is
manipulated to produce specific desired results,”
and that “in the coming century, the principal
[sic] focus will shift from medical science to
medical engineering. Nanomedicine will involve
designing and building a vast proliferation of
incredibly efficacious molecular devices, and then
deploying these devices in patients to establish
and maintain a continuous state of human
healthiness.”
In
order to understand what Freitas means by
“healthiness,” we turn to Freitas’ definition of
disease. Typically, Freitas doesn’t just casually
state that disease is such-and-such. Instead, he
describes no less than eight previously-proposed
definitions of disease, complete with a graphical
illustration of opinions as to what constitutes a
disease, before proposing his own definition, the
“volitional normative model” of disease.
Essentially, in the era of nanomedicine, disease
is a failure to attain optimal functioning, and
optimal functioning is defined by the wishes of
the patient. In other words, ideal health is
whatever the patient wants it to be. Nanomedicine,
Freitas tells us, is charged with the duty of
making the patient’s wishes, whatever they may be,
come true. This begins to hint at the capabilities
projected for nanomedicine. Essentially,
nanomedicine will mean that, if a given individual
wants to, he or she can go beyond being
disease-free, and can enjoy the conditions of
being free of aging, free of vulnerability to many
traumatic events that today would be fatal, and,
finally, free of the limitations of the present
human body plan. As Freitas says in considering
the relevance of a historical perspective on
nanomedicine, “another important reason to study
the history of medicine is to gain a deeper
appreciation of the long, hard struggle to improve
human health, a struggle that is expected finally
to culminate in victory in the 21st century.”
That’s victory in the final sense, the virtual end
of the battle.
 The concept
of nanomedicine is clearly and squarely based on
the concept of molecular nanotechnology, which is
a general ability to manipulate matter to atomic
precision. This foundation is secure. The
intellectual soundness of molecular nanotechnology
was established with the monumental work by K.
Eric Drexler, Nanosystems: Molecular
Machinery, Manufacturing, and Computation
(John Wiley and Sons, New York, 1992). As Ralph
Merkle states in his excellent Afterword to
Freitas’ book, “Nanosystems was
published in 1992, and no significant flaws have
been found. Given the volume of public debate and
the number of people who have read the book, the
simplest explanation for this absence of reported
errors is that its logic is basically correct and
its conclusions are basically sound.” If we are
made of atoms, and molecular nanotechnology allows
us to put our atoms anywhere we want, and attach
or detach them from any other atoms as we may
please, then it does stand to reason that we’ll be
able to control our health almost totally. As Eric
Drexler states in his masterful Forward to Nanomedicine, “these are
not high-risk predictions, but merely the
extension of currently-observable progress in
biological and medical research. . . . What was
visionary a short time ago is now a minimum
baseline expectation.”
However, simple assertions have little
force unless they are backed up with rigorous
analysis. As Carl Sagan once remarked in another
context, extraordinary claims require
extraordinary evidence. And Robert Freitas is here
to give it to us.
Nanomedicine is a book
of 509 pages of fine print that could easily have
been 2000 pages at a normal font size. The last
citation is numbered 3728. There are 210 figures,
58 tables and over 270 equations. Freitas reports
in his preface his expenditure of about 19,000
hours of effort, or essentially 10 man-years, in
putting together the work, and it shows. The
results are such that I believe it will be hard if
not impossible for even zealous skeptics, if any
still remain, to remain deeply skeptical of
Freitas’ vision upon close reading of this book,
barring the abdication of intellectual honesty and
reason. Freitas provides what amounts to an
intellectual battering ram capable, I believe, of
breaking through the ignorance and resistance of
anyone who is actually willing to view
nanomedicine on its merits, and capable of
understanding what Freitas says.
Nor can Freitas be dismissed as a mere
unqualified enthusiast. Freitas has formal
credentials for writing such a work. According to
the book jacket, he has degrees in physics,
psychology and law, has written and published
extensively, co-edited a seminal NASA study on the
feasibility of self-reproducing factories in
space, and wrote the first published technical
design study of a medical nanorobot that appeared
in a peer-reviewed biomedical journal.
Nanomedicine is
organized in a logical series of chapters. The
first is entitled “The Prospect of Nanomedicine,”
and takes a look at nanomedicine in the context of
the broad sweep of history, starting with
fossilized pathogens dating back 500 million
years, and culminating in a detailed description
of modern contributions to the idea of
nanomedicine, the differences between nanomedicine
and more conventional approaches, and an idea of
how a visit to the doctor would be different in
the era of nanomedicine.
Chapter two is a vital one, “Pathways
to Molecular Manufacturing.” Since we can’t build
nano devices now, it is imperative to at least
provide evidence that we will one day have that
capability. Freitas, to his great credit, provides
an exceptionally detailed look at how existing
capabilities can be channeled into the beginnings
of molecular nanotechnology, and how these
beginnings can, in turn, develop into full-fledged
molecular and machine manufacturing capability.
Not only does this provide justification for
considering what the results of this process will
ultimately be, but it also helps to instruct
present-day nanotechnologists on how they can
proceed.
Having set
this stage, the book then proceeds through a
series of chapters on the nuts and bolts issues of
creating and safely operating medical nanodevices
and networks. Chapter three focuses on “Molecular
Transport and Sortation,” chapter four on
“Nanosensors and Nanoscale Scanning,” chapter five
on adaptable shapes (“Metamorphic Surfaces”) for
nanodevices, chapter six on powering medical
nanodevices, chapter seven on communication with
and between nanomedical devices, chapter eight on
the related topic of navigation, and chapter nine
on the crucial issues of “Manipulation and
Locomotion.” Finally, chapter 10 discusses “Other
Basic Capabilities,” including timekeeping,
molecular computing, handling of high and low
pressures, extermination of viruses and aberrant
cells, solubility issues, and a discussion of
locomotion through and excavation of ice.
Appendices A-C give reference data of various
kinds (physical constants and conversion factors
in A, a comprehensive list of all of the molecules
found in blood and their concentrations in B, and
a catalog of most distinct cell types in the human
body in C). Following this is an extensive
glossary, reference list and index. The glossary
is needed since, in addition to the numerous
arcane words available before Nanomedicine, Freitas is
forced to coin innumerable terms (such as
“histonavigation,” “vasculography” and
“communicyte”) in order to describe the new
devices and capabilities he envisions.
The purpose of chapters
3 to 10 is to establish something akin to a parts
list for nanomedical devices and a set of
performance standards for such parts. Nanomedical
devices have to be made out of components that do
specific things, occupy specific volumes, respond
at specific rates, and operate with specific
tolerances and with specific power requirements.
Once these components are characterized, it
becomes more feasible to talk about what can be
done by combinations of components. In addition,
Freitas provides enormous context to such
discussions by citing example after example of
archaic, contemporary, and projected designs and
working examples pertinent to each subtopic being
considered.
It isn’t
possible in a short review to provide a detailed
account of or critique of each specific topic area
considered in Nanomedicine. Instead,
lets take as an example just one topic area of
particular interest, the nanomedical computers
needed to permit cell repair machines to operate.
There isn’t much point in talking about what an
intracellular computer will be programmed to do if
you can’t first establish what the intracellular
computer’s core design limitations will be.
Drexler extensively discussed molecular computers
in Nanosystems,
but didn’t consider the problems of running such
computers under the biological constraints that
exist in a living system, constraints which are a
specific nanomedical, as opposed to merely a
global nanotechnological, problem. Nanocomputer
performance is important to nanomedicine in many
different ways in dealing with many different
problems, so it’s important to think carefully
about what can be expected from medical (in vivo)
nanocomputers.
 I myself
had analyzed, in a presentation before the
American Academy of Anti-Aging Medicine, the
problem of heat production by intracellular
nanocomputers, and had to conclude that clock
speeds similar to those in today’s PCs would be
problematic in cells unless more energy-efficient
architectures than those described by Drexler were
adopted. Nanocomputers as described by Drexler
dissipate relatively large amounts of heat
compared to the remarkably subtle energy
expenditures of typical cells. I was therefore
quite interested to see what Freitas would say
about these matters.
Surprisingly, it turns out that one
could double cell and whole-body energy
expenditure with only a 0.4oF increase in body
temperature, so efficient are natural body systems
for dissipating excess heat. For comparison, a
body exercising at maximum capacity increases
energy expenditure by a factor of 16 (with a rise
of only about 6oF). Given that cells already
repair virtually all damage already, it isn’t hard
to imagine that we could repair all
currently-unrepaired biological injury if we
devoted equal energy to doing this. It’s also not
hard to imagine that we could do much to repair
traumatic injury if we devoted 15 times our normal
energy expenditure to this task during
emergencies, even if most of this energy
expenditure represented computational “thinking”
about repairs rather than the actual conduct of
the repairs themselves. (Of course, heat
dissipation mechanisms could be limited as a
result of certain kinds of trauma, but this still
leaves substantial room for augmented healing
capacity.) In summary, the simple physiological
context provided by Freitas, in his typically
near-exhaustive treatment of issues, is
reassuring. Incidentally, it is worth pointing out
that in order to double your metabolic rate, you
would have to eat twice as much in order to avoid
losing weight. This is bound to be an attractive
“side effect” of nanomedicine. If you didn’t want
to eat that much, we learn that popping a couple
of high-energy pills containing coated powdered
diamond could support the extra metabolism for
days.
On a more
fundamental level, Freitas brings us up to date on
a plethora of new, more energy-efficient computer
information processing architectures, including
even a discussion of the upcoming field of quantum
computers, wherein the superposition principle
could allow a single carbon atom to retain 100
million bits of information and process it at the
rate of around 1026 bits/second! Moreover, a tamer
form of logic called helical logic by its
developers, Merkle and Drexler, could cut the
energy requirements of Drexler’s original rod
logic system by a factor of around 10,000, and
reversible computers could extend this advantage
considerably more. The vast scope for creating
more energy-efficient nanocomputers in combination
with the increased energy expenditure permitted by
natural human physiological temperature
compensation systems seems ample to allow most
nanomedical problems to be tackled with large
safety margins.
One
notable apparent gap in the argument is Freitas’
virtual silence about the required investment of
chemical energy needed to carry out the actual
biochemical reactions needed to effect repair.
Given our long lifespans, it seems likely that
elimination of currently-unrepaired damage under
baseline conditions would require less than 1% of
normal basal metabolic energy expediture, which is
well within comfortable working conditions. On the
other hand, major trauma might require a vast
expansion of chemical reactions on biomolecules,
and it will be important for Freitas to specify
how the partitioning of the nanomedical energy
budget between the requirements of the nanodevices
themselves on the one hand and the requirements
for producing chemical changes in biomolecules on
the other is likely to be constrained. It may be
that the energy needs of the nanodevices dwarf or
even encompass the additional costs of performing
chemistry on the target molecules, but these
issues will have to be made more explicit in the
future.
Fortunately,
additional information will in fact be
forthcoming. The current book is only Volume 1 of
what will eventually be a three-volume treatise.
Although it is hard for this reviewer to endure
the present absence of Volumes 2 and 3, Freitas
does at least share with us, at the end of chapter
one, a glimpse of what these volumes will contain.
Volume 2 will be subtitled “Systems and
Operations.” It will consider such subjects as
control, repair and replacement, safety and
reliability, deployment configurations,
performance, examples of specific nanorobot
devices, reading and editing of biological
molecules, enabling systems for cell repair, the
manufacturing of tissues and organs, and personal
defense systems. Volume 3 will be subtitled
“Applications.” Volume 3 will consider
proofs-of-concept, treatment of pathogens and
cancer, reversal of trauma and injury from
radiation and burns, emergency care, brain repair,
control of aging and most causes of death
prevalent today, biostasis (suspended animation),
human augmentation (meaning the addition of new
capabilities and features to the human body), and
the social implications of nanomedicine.
The greatest weakness of
the book, I believe, is the lack of integration of
the reference list. The reference list runs to
over 3700 references, but not all references
exist—for example, references 2-5, 7, and 22-26
aren’t in the list. To exacerbate the situation,
the references are listed in no particular order
other than the fact that the citation numbers
themselves run sequentially, and perhaps a weak
correlation between the citation number and the
order of citation in the text. It is effectively
impossible to infer from the reference number
where the reference is cited in the book, and it
is impossible to easily find cited authors’ names
due to the lack of alphabetization of the
reference list. This is a clerical issue that can
obviously be overcome in a future edition and was
undoubtedly the result of a publishing deadline
that precluded the herculean task of shuffling so
many citations into a coherent pattern. In any
case, if one reads any passage of interest in the
book, the citations appearing in that passage can
be found readily in the list, so the list does
serve its primary purpose of backing up what is
said in the book.
Another weakness of the book is the
figures. They are of admirable content, but of
less-than-stellar quality and size in many cases.
This was probably a necessary compromise to keep
the price of the book in the readily-affordable
range. Nevertheless, the figures amply illustrate
the points they are intended to illuminate.
From time to time it is
apparent that Freitas is a masterful engineer or
mathematician, but not a biologist by training.
Little quirks such as reference to a “neuron cell”
instead of to a “neuron” (Table 6.8) appear
infrequently. Such tiny glitches, however, only
serve to underscore the magnitude of Freitas’
achievement in crossing disciplinary barriers to
write a book that is really about biology, a field
that is not his area of formal training.
It is possible that
Nanomedicine will
for many years be like Stephen Hawking’s A Brief History of Time,
a book that many people considered important
enough to buy, but that most people could not
read, and that mostly ended up on the coffee table
to impress guests. If so, then I urge the reader
to decorate his or her coffee table with this
book. We should support Freitas’ superhuman effort
because, in so doing, we will be helping in a very
palpable way to create the future we all dream of
and that our lives will ultimately depend upon. As
Ralph Merkle’s Afterword says, “Nanomedicine is more
than just a description of what might be, it is a
call to action.”
Happily, the Foresight Institute has
announced that Mr. Freitas is joining Zyvex, the
first company devoted to creating a
nano-assembler. Zyvex will financially support the
completion of Volume 2 and Volume 3, thus freeing
up Rob Freitas for this monumental work. This is
good news both for the future of Nanomedicine and for the
future of nanomedicine. Stay tuned. —Gregory M. Fahy,
Ph.D. |
