The advance in smart material technologies includes the capability of self replication. Studies in this area started in the last decade and exploited the results of Nature: using DNA strings with attached molecules of materials scientists demonstrated the possibility of replication (see the image). Of course the replication instructions to be effective require the presence of basic components for the assembly. As a matter of fact this is what happens in Nature for living beings: the code of life direct the cellular processes in the assemblage of molecules to obtain the desired material (a protein). Living being consists of many processes orchestrated at the individual level. All together they result in the provisioning of basic molecules to these manufacturing engines inside the cells. Hence, we can say that self-replication for living beings involves both a top down approach to provide basic components and a bottom up approach to replicate materials (we eat and our digestive system delivers the basic components to the cells where DNA provide the assemblage instructions). Notice that in living being part of the top down approach is also providing the energy that is used in these processes as well as in the bottom up ones.
So far scientists have been working on the bottom up part, when looking at the possibility of self replicating materials. The basic components are provided by the environment. This does not mean that research has neglected the aspects of energy harvesting and material decomposition but so far the complexity is such that we do not have achieved a complete process. By the way, such a complete process would be pretty close to a living being … and we are not there yet (although scientists have been able to move the first steps in that direction).
For the sake of this series of post the focus is on the industrial aspects of self-replication, hence the interest in mastering an industrial process for self-replication and the assumption of availability of basic components. In this sense the self replication in smart materials is about being able to transport the information of the structure of a material to a number of molecules (components) in such a way that they can -through self organisation- create a structure that mirrors the original one.
This has been approached by nanotech and it is being used in various industries. A nice overview of the challenges and approaches can be found in the book: Kinematic Self Replicating Machines.
More recently scientists have been applying Nature’s way of self replication to bio materials, watch this clip by Cornell University:
This bottom up approach, typical of nanotechnologies is being flanked by a software approach to enable an articulated (self powered) structure to assemble a copy of itself by using existing basic components, as shown in the following clip. This opens up the possibility of endowing complex artificial organisms, like robots, of self replication capabilities, as I will discuss in the next post.