Artificial DNA
© KTSDESIGN/SCIENCE PHOTO LIBRARY/Getty ImagesArtificial DNA is a hot focus for roboticists.
It's long been a dream of many to build robots that look and act like humans. After all, there's a reason that the most beloved robots from entertainment and culture - C3PO from Star Wars, or Data from Star Trek, for instance - are so humanlike.

But rather than build them out of batteries, central processing units, servos and hydraulic joints, what if artificial lifeforms could be made using technologies that mimic the biochemical processes of life itself?

A team at Shanghai Jiao Tong University in China might have just taken the first step, using DNA-based materials that undergo cycles or growth and decay by mimicking processes found in biological metabolism.

In a paper published in the journal Science Robotics, Shogo Hamada and colleagues report the invention of a system they dub DNA-based Assembly and Synthesis of Hierarchical materials, or DASH. They describe it as a "bottom-up construction of dynamic biomaterials representing a combination of irreversible biosynthesis and dissipative assembly processes".

The researchers started with two mixtures that behave as microfluids, able to move in confined spaces and narrow channels without external force acting on them. The first had the ingredients needed to assemble DNA structures and the other had the ingredients needed to degrade them.

The DASH crew injected each mixture into microscopic chambers. Confocal fluorescence microscopy and scanning electron microscopy revealed that self-generating DNA had formed, filling the chamber in the same directed, step-by-step approach as biological metabolism.

The structures then degenerated as new ones were formed. The liquid mixtures acted very much like a living cell as it forms and breaks down materials to keep itself and its host organism functioning.

The DASH material degenerated after a fixed period before regenerating again, restarting the cycle twice under its own steam.

And while it is indeed very lifelike, the difference between DASH DNA and truly biological DNA is that the former can be programmed as the designer sees fit.

By using different pathways through the channels and obstacles in the mixing chambers, or by tweaking the ingredients, DASH can be directed to move like a slime mould. DNA growing at one end of a structure can be made to break down, as fresh material is created at the other, making the whole effectively crawl along a surface.

Hamada and colleagues consider the results to be bioengineered machines, complete with emergent regeneration and locomotion behaviours.

Combining enough artificially metabolising "cells" together to build a human-scale bioengineered robots is probably a long way off.

However, there are already areas DASH to which could be applied, such as the development of hybrid nanomaterials for use in personalised medicine.