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Bio-Nanorobotics 219

The concept of self-replicating mechanisms (SRM) or mimetics of life is not new (Freitas and
Merkle, 2004). We are perfect examples of these kinds of systems. We are wounded and our
internal mechanisms heal it with some differences in some cases. Taking the example of the wound
and its healing process, we move ahead and try to analyze how we can achieve such behaviors in the
mechanisms that we design. At the core of the concept of self-replication lies the basic material
(DNA/RNA) which undergoes such activity. Though we hardly know why these materials behave
in this fashion, what we do know is how they behave and this provides the stepping stone for us to
move ahead.
Before looking at some of the possible designs, a brief discussion on the application of such
mechanisms is necessary. Why do at all we need living systems or self-replications? Where would
they be best suited?

7.4.2 Applications

(a) Consider that our application depends upon a particular part — mechanical or electrical, or any
other physical, biological, or chemical element — which fails or starts developing problems. We
need self-rectifying mechanisms within our application to detect the problem and rectify it. It
is similar to our example of the wound. We can think of many applications where we would
desire such behavior. Given some initial material feedstock, it would be desired that the self-
replicating mechanisms would rectify the problems. Having said that, we can classify the
self-replicating mechanisms in the order we classify our main mechanisms or machines:
. mechanical self-replicating mechanisms;
. electrical self-replicating mechanisms;
. chemical or biological self-replicating mechanisms.

There could be other classifications as well and numerous other examples following the lines of our
wound example, can be thought of. It just depends on our imagination. For example, suppose that
we build some SRM which mimics the living system. Its function is to detect the crucial defect in a
mechanical element and then mend that defect. If we are able to devise such an application, it could
significantly enhance the life and performance of the system. The system in this example would be
designed and constructed to work at nano-scale, and therefore it would have an ability to detect the
slightest of defects and start working towards rectifying it.
(b) Remote Applications would also benefit from SRM systems. Maintaining remote applica-
tions requires constant human interaction. If these systems mimic the coded logic and goals of the
living system, then it would be able to perform optimally with minimal human interventions. For
example, deep space explorations would require circuits, machines, and equipments to adjust and
adapt with time and as per the conditions they would be subjected to.
(c) Applications at the nano-scale. This category of applications would be most influenced by
our biomimetic systems because they could lay the foundations of nanodevices that have the
capability of manipulating molecular matter.
In the following section we try to define some of the guidelines and working philosophies for
designing and fabricating such replicating systems. The details are the thoughts and ideas of the
authors and are not verified or supported by experimental facts.

7.4.3 The Design of Life-Mimetic Systems

The design of life-mimetic systems requires new innovative materials to be designed that behave in
the same fashion as that designed by nature. These new materials are termed ‘‘intrinsic materials’’
from here on.