Wed 1 May 2013
3D printers are very much in vogue and used for everything from spectacle frames to jet engine components. They work by building up a 3D form one thin layer at a time. A variety of materials can be used depending on the desired properties of the resulting component.
I believe we should learn from nature. If you look at natural materials constructed by living organisms, it is really remarkable what has been achieved, for instance, hair, feathers, skin, teeth and bones. Insects are amazing to look at under the microscope and come in all sorts of weird forms. The structure of an insect’s antenna, or a butterfly’s wings are incredible.
The cell is a powerful molecular computer. At its heart, DNA provides the storage for the program. The human genome is said to be about three thousand million bits in size. The cell makes use of a complex set of molecules to determine which parts of the genome are being transcribed into proteins at any one time. The architecture is unlike any digital computer we are familiar with. The cell’s state is distributed across many components, and updated in complex chemical pathways. We are gradually improving our understanding of how they work together as a system.
It is now time to study how to create synthetic cells and learn how to utilize these to create complex materials we can use in a future generation of products. For this purpose, we will have to start relatively simply by studying particular subsystems without the need to fabricate the full complexity seen in living cells. This functional approach also has the great advantage of avoiding the risk of creating a new breed of organisms that can escape to the environment and replicate themselves unchecked.
The first step is to study how to create a molecular computer with DNA, RNA, ribosomes, enzymes and so forth. Can we build a system where we can design a program, translate it into DNA, and used it to switch on and off which parts of the DNA are being transcribed, and to update the state of the synthetic cell in predictable and controllable ways? Once that is achieved we could go on to develop the functional components needed to form a 3D assembler. These include counters and timers, as well as how to control the functioning of a synthetic cell according to its neighbours, or to chemical or electromagnetic gradients.
A working system would involve a means to design a program and translate it into DNA, to massively replicate this and assemble the synthetic cells from the raw ingredients, and then trigger them to start the assembly of the desired components in a carefully controlled environment. The synthetic cells would be unable to replicate themselves, and designed with only one purpose in mind.
The benefits of this approach would be the ability to create a very wide range of complex materials and forms from readily available raw materials in an energy efficient process. Today’s manufacturing processes aren’t sustainable in the long run as they use large amounts of energy and rely on materials that will increasingly be in short supply, for example, copper for electrical conductors and rare earths for electronic components and touch screens in smart phones. Biological processes by contrast make use of trace amounts of materials and as such are much more sustainable.
The time has come for a sustained programme of investment into research in molecular computing and synthetic cells. This is essential for sustaining a high standard of living as we move into a lasting era of increasingly expensive raw materials.