Isaac Asimov was a great science fiction writer, but even the best has his off days, and Asimov’s low point was probably his involvement with the dire science fiction movie Fantastic Voyage. Asimov wasn’t responsible for the story, but provided the novelization – and he probably regretted it. The premise of the film was that miniaturization technology has made it possible shrink a submarine and its crew down to around 1,000 nanometres, sending it into a man’s bloodstream to find and destroy a blood clot on his brain.
Along the way the crew have various silly encounters with the body’s
systems – but strip away the Hollywood shlock and underneath is an idea
that has been developed in a lot more detail by IT pioneer and life
extension enthusiast Ray Kurzweil. Based on the idea of miniature
robotic devices – nanobots – Kurzweil believes that in the future we
will not have a single manned Proteus submarine as featured in Fantastic Voyage
in our bloodstreams but rather a whole host of nanobots that will
undertake medical functions and keep humans of the future alive
As we have seen in The Importance of Being Wet,
the chances are that any such devices would not be a simple
miniaturization of existing mechanical robots with their flat metal
surfaces and gears, but rather would be based on the wet technology of
the natural nanoscale world.
the possibilities Kurzweil suggests are on the cards are
self-propelling robotic replacements for blood cells (this eliminates
the importance of the heart as a pump, and hence the risk of heart
disease), built in monitors for any sign of the body drifting away from
ideal operation, nanobots that can deliver drugs to control cancer or
remove cancer cells, and even miniature robots that make direct repairs
Kurzweil also expects we might separate the pleasure of eating from
getting the nutrients we need, leaving the latter to nanobots in the
bloodstream that release the essentials when we need them, while other
nano devices remove toxins from the blood and destroy unwanted food
without it ever influencing our metabolism. You could pig out on
anything you wanted, all day and every day, and never suffer the
consequences. (Given Kurzweil is notorious for living on an unpleasant
diet to attempt to extend his life until nanotechnology is available,
perhaps this is wishful thinking.)
If we are to develop this kind of nanotechnology, there are two
aspects of nature that we will need to use as guides. One is to listen
to the bees. Bearing in mind just how small a medical nanobot would have
to be, even with the best developments in electronics the chances are
it would have to be relatively unintelligent – yet it would need to
achieve quite complex tasks. Bees are an excellent natural model for a
way to achieve this.
A colony of bees achieves remarkable things in the construction and
maintenance of its hive – yet taken as individuals, bees have very
little capacity for mental activity. The realization that transformed
our understanding of bees is that they form a super-organism. In effect,
a whole colony is a single organism, not a collection of individual
bees. A bee is more like a cell in a typical animal than it is a whole
creature. By having appropriate mechanisms for communicating between the
component parts – in the case of bees, using everything from chemical
scent markers to waggle dances – relatively incapable individuals can
come together to make a greater whole.
It would be sensible to expect something similar from medical
nanobots at work in a human body. Individually they could not be
intelligent enough to carry out their functions properly – but
collectively, if they can interact to form a super-organism, they could
operate autonomously without an external control mechanism continuously
providing them with orders.
A second model for these miniature medics is a piece of natural
nanotechnology that we usually regard as a bad guy – the virus. Viruses
are very small – typically between 20 and 400 nanometres in size – and
they lack many of the essential components of a living entity. However
they are able to reproduce and thrive by using a remarkably clever
cheat. Lacking the physical space to carry all the components of a
living cell, they take over an existing cell in their host and subvert
its mechanism to do their reproduction for them.
particular class of virus that may be particularly useful as a model
for medical nanobots is the phage. These are amongst the weirdest
looking natural structure – some have an uncanny resemblance of the
Apollo Lunar module: they actually look as if they are the sort of
nanotechnology we might construct.
The word ‘phage’ is short for bacteriophage – ‘bacteria eater’. These
are viruses than instead of preying on human cells – or those of any
other large scale animals – attack and destroy bacteria. Because there
are so many bacteria out there (even the human body has ten times more
bacteria than human cells on board), their predators are also immensely
populous and diverse. Phages may not be common fare on David
Attenborough’s nature programmes, but they play a major role in the
overall biological life of the Earth.
Because phages attack bacteria, they can be beneficial to human life.
Throughout human existence we have been plagued with bacterial
infections. (Literally – bacteria, for example, cause bubonic plague.)
It is only relatively recently that antibiotics have provided us with a
miracle cure for bacterial attacks – but that miracle is weakening.
Bacteria breed and evolve quickly. There are strains of bacteria that
can resist most of the existing antibiotics. But phages have the
potential to attack bacteria resistant to all antibiotics. For a long
time phage therapy was restricted to the former Soviet Union, but
interest is spreading in making use of phages in medical procedures.
The biggest problem with phages is getting them to the right place.
But medical nanobots based on a phage’s ability to attack or modify
particular cells, combined with a super-organism’s ability to act in a
collective manner would have huge potential. Modified viruses are
already used to insert genetic payloads into cells – but the
nanotechnology of the future, inspired by the phage and the bee, could
see something much closer to Kurzweil’s vision.
Moving away from the medical, and from individual nanoscale elements, in the next installment of Nature’s Nanotech
we will see how natural nanotechnology plays a role in silk and how
fibres based on a nanotechnology structure could make rockets obsolete
for putting satellites into space.