They can manufacture limitless copies of themselves

Made from a few strands of DNA, researchers have created a programmable nano-scale robot that can make duplicates of itself and other UV-welded nano-machines by grasping and arranging other DNA snippets.

A thousand of the robots might fit onto a line the width of a human hair because, according to New Scientist, they are only 100 nanometers across and are made of just four strands of DNA.

As reported here, and according to the team from New York University, the Ningbo Cixi Institute of Biomechanical Engineering, and the Chinese Academy of Sciences, the robots outperformed earlier tests in which they could only put pieces together to form two-dimensional structures. The new bots can perform “multiple-axis precise folding and positioning” in order to “access the third dimension and more degrees of freedom.”

dna-folding nanobots
Three-dimensional self-replicating nano-robots built from just four strands of DNA

The nanobots, according to Andrew Surman, a King’s College London nanotechnology expert who was not involved in the study, are an improvement over earlier self-assembling DNA robots that could only form two dimensions. Compared to trying to fold 2D structures into 3D, errors are decreased by permitting precise 3D folding from the ground up.

As in biological systems, accurate folding of proteins is essential to functionality, and Surman claims that the same is true for synthetic nanostructures.

These nanobots are frequently thought of as potential means of producing drugs, enzymes, and other chemicals—possibly even inside the body’s cells. That being said, the researchers draw particular attention to the machines’ ability to “self-replicate their entire 3D structure and functions.”

They are not fully self-contained, but “programmable.” The robots react to temperature and UV light that are controlled outside, and they need the UV light in order to “weld” the DNA fragments they are building.

According to University of Plymouth nanotechnology researcher Richard Handy, the DNA nanostructures serve as a scaffold or mold to create copies of the original structure or other desired nanostructures. This could make it possible for the body’s cells to produce proteins, enzymes, or drugs.

Surman and Handy do point out several restrictions on the process of self-replication, though. Raw materials include specific DNA chains, certain molecules, gold nanorods, and exact cycles of heating and cooling. While Handy warns that there are always uncertainties in complex biological systems, this renders scenarios involving uncontrollable “grey goo” (a hypothetical worldwide catastrophe involving molecular nanotechnology in which uncontrollably self-replicating machines devour all biomass [and maybe everything else] on Earth while reproducing repeatedly) implausible.

In general, DNA nanobots are a significant advancement, but to fully realize their potential and minimize hazards, they will need to be developed responsibly and with ongoing safety measures.

This nanotechnology could potentially revolutionize the medical field, but it also opens the way to new risks since everything it cures is also a potential weapon.