From: mmm@cup.portal.com (Mark Robert Thorson)
Newsgroups: alt.cyberpunk.tech
Subject: World-Killing Nanovirus (How to Build)
Date: Thu, 30 Jul 92 07:28:19 PDT
Organization: The Portal System (TM)

A big concern people have about nanotechnology is the possibility
that it could be used to create very destructive self-reproducing
machines.  Today I was thinking, what would be the _minimum_
nanotechnological machine which could kill Mankind?  A RISC
doomsday virus, so to speak.

Would it need to have a nanoassembler?  Would it need to have a
computer?  Would it need an energy source?  Would it need
propulsion machinery?

Obviously it needs to be self-reproducing, in order to pose any threat
to Mankind.  A few biological systems are self-reproducing but do
not have an energy source or their own reproductive mechanism.
These things (viruses) hijack the energy and reproductive
mechanism of a host.

I believe Nature has already pushed virus technology near to its
limits, and therefore there is limited profit and lots of competition
in using the technology of biological organisms for reproduction.  The
proposed Wonder Bug should use a nanoassembler of its own
for reproduction.  This would be like a pick-and-place robot arm
at a molecular scale, which would build additional copies of Wonder
Bug using available materials.

However, I also believe the optimal solution is for Wonder Bug to
parasitize energy from its host.  This solves a lot of problems with
regard to having an energy source.  It also engages Wonder Bug
into a mechanism it can use to kill its host.

Among the cellular structures found in animal cells, there is one type
of organelle (i.e. internal cell organ) which always has an electrical
voltage drop from its inner surface to its outer surface.  These are
the mitochondria, which convert sugar to ATP.  Sugar is supplied
to the cells, and the mitochondria convert ADP to ATP using the
chemical energy of the sugar.  The reaction which converts ATP back
to ADP yields energy, which is the reaction which drives all other
chemical reactions in the cell.  Sugar is the medium of distribution of
energy outside the cell, and ATP is the distribution medium inside
the cell.

The enzymes embedded in the cellular membrane of the
mitochondrion can be divided into two sets.  One set digests sugar
in order to inject a hydrogen ion into the mitochondrion.  Hydrogen
ions are totally ubiquitous in the cellular fluid.  By pumping
hydrogen ions into the mitochondrion, a voltage forms across
its cellular membrane like a battery (actually, like a fuel cell).

The other set of enzymes converts ADP to ATP.  This set is powered
by the membrane voltage.

Wonder Bug will embed itself in the membranes of mitochondria.
It will draw power from mitochondria for self-reproduction.
Wonder Bug will swim about blindly in animal tissue until it senses
the voltage drop which indicates it has pierced a mitochondrion.

Wonder Bug will not need active propulsion machinery.  Wonder Bug
is barbed, like the stinger of a bee.  The normal stretching and
contraction of animal tissue caused by activation and relaxation
of muscles will propel Wonder Bug.  When Wonder Bug senses the voltage
drop of a mitochondrial membrane, it retracts its barbs.

Wonder Bug just swims around, passively and randomly, until it
finds energy. Then, it becomes activated.  It goes to work
reproducing Wonder Bugs.

Wonder Bug might not need a computer.  Before computer-controlled
machine tools were invented, machine tools for reproducing shapes
_did_ exist.  These were called tracer mills.  The first computer-
controlled machine tool was in fact a modified Cincinnati Milacron
tracer mill interfaced to an early vacuum tube computer (MIT's
Whirlwind 1).  A tracer mill has a tracer head, which follows the
contours of a model part.  The contour sensed by the tracer head is
used to control the motion of a cutting head, which cuts a replica
of the model from a block of blank metal.

The earliest tracer machinery are Revolutionary War era tracer
lathes that were used for automatic cutting of gunstocks.  A tracer
lathe is much simpler than a mill.  The model and workpiece rotate
on parallel shafts in synchrony, and there is a bar which rides the
surface of the model.  A blade on the bar cuts the workpiece down
to the same diameter as the model.  A screw mechanism slowly
advances the bar, so that it covers the whole length of the model.

A minimalist nanoassembler might be a tracer device, with no
programmability.  It might just squirt out additional Wonder
Bugs when it encounters favorable conditions.  By homing in on the
mitochondrial environment, all the molecules typical of that
environment can be assumed to be available as raw materials.

Spread of the contagion is facilitated by its blind penetration of all
tissues.  Some will inevitably penetrate the lungs, from which they
can be expelled to the atmosphere.  If it would be convenient to
have programmable surface properties, Wonder Bug should respond
to a drop in temperature below nominal body temperature by
assuming a Teflon-like external surface.  This will minimize adhesion
to the inner surface of the lungs.  The cool incoming breath will
loosen Wonder Bugs from the lungs, and they will be swept out
when the breath is exhaled.

I anticipate that infection will be lung-to-lung, like the Black Death
(pneumonic plague).  Wonder Bugs that are inhaled will quickly
burrow into the lungs due to the stretching and contraction of the
lung tissue caused by breathing.

If Wonder Bug were quickly lethal, its own lethality would limit
distribution.  For maximum effect, Wonder Bug should be like a
time bomb like AIDS, i.e. people can be infected and spread the
disease for many years without knowing they have it.

Wonder Bug should therefore have an internal clock/calendar so that
it remains silent until Special Day.  On Special Day, all Wonder Bugs
become a short circuit across everybody's mitochondrial
membranes, causing sudden instant death by cutting off the
ADP -> ATP reaction.

The calendar is driven by daily fluctuations in cellular chemistry.
A binary counter could be used to tick off the days, so everybody
gets killed at once and society has no time to respond.
Newsgroups: alt.cyberpunk.tech