Bioengineers at the California Institute of Technology have created a DNA nanorobot that has a hand to pick up molecules and two feet to take them to the desired location. At the moment it is a little slow, since it takes five minutes to take a small step of 6 nanometers, but its creators hope to accelerate this novel system, which one day could operate inside the human body.
Imagine a robot that helps you order your house: lurk looking for the socks and take them to the laundry basket, or pick up the dirty dishes to put them in the dishwasher. It looks like science fiction, but now scientists from the California Institute of Technology (Caltech, in the US) have created a molecular machine that can perform similar tasks at the nanometer scale.
The nanorobot is made with only one strand of DNA and can ‘walk’ autonomously, collecting molecules in one area of one surface and placing them in another. The details of the system, which in the future could be used to assemble chemical compounds or reorganize nanoparticles in circuits, are published in the journal Science.
“Just as electromechanical robots can be sent to faraway places, such as Mars, we would like to send these molecular robots to tiny places where humans can not travel, like the bloodstream,” explains Lulu Qian, coauthor and professor at Caltech. “In particular, our goal was to design and build this nanorobot to perform a sophisticated task: ordering a cargo (molecules in this case)”.
These tiny machines take five minutes to take a step of 6 nanometers, but they place the transporting molecules in place.
To assemble the DNA robot the researchers built three pieces: a kind of ‘leg’ with two ‘feet’ to walk, an ‘arm’ with a ‘hand’ to pick up the load, and a third segment that recognizes a specific point where leave it, indicating to the ‘hand’ to release it. Each of these components is made with a few nucleotides within a single strand of DNA.
In principle, these modular building blocks could be assembled in many ways to perform different tasks. For example, a DNA robot with several arms and hands could be used to transport a multitude of molecules at a time.
But, for now, the authors have made a nanorobot that explores a molecular surface in which it can collect two types of molecules: a yellow fluorescent dye and another pink -also fluorescent-, and then distribute them in two different regions.
The use of fluorescent molecules allowed the authors to verify that the molecules ended each one in its place. The robot successfully ordered six scattered molecules (three roses and three yellows) in their correct areas in 24 hours. If more robots were put on the surface, the time was shortened and the task was completed first. Overall, the probability that each robot successfully delivered the cargo was around 80%.
“Although we have developed this robot for a specific task, the same system design can be generalized to operate with dozens of load types located at any arbitrary initial location on the surface,” says Anupama Thubagere, another Caltech researcher, ” and one could also have a multitude of robots performing different classification tasks in parallel “.
The authors point out that the time that robots need to deliver their cargo could be greatly reduced if they were also put ‘tails’ of a single chain, or using motor proteins programmed with DNA.
The nanotablero that is covered in a day
On the other hand, using the same physicochemical principles, the team has designed not only robots, but also molecular ‘playgrounds’ where they can be put to the test. In this study they worked with a square board of 58 nanometers on each side, in which, as if they were pins, individual strands of DNA complementary to that of the leg and foot of the robot were inserted.
This is attached to a ‘peg’ with his leg and one of his feet. The other foot floats freely, and when the random molecular fluctuations cause this free foot to find a nearby pin, pull the robot towards it and release the other foot. This process continues with the robot moving in a random direction in each step.
It can take a whole day for the robot to explore the entire board. Along the way, when you find cargo molecules attached to the pegs, he grabs them with his hand and carries them until he senses the signal of point of descent. The process is slow, but allows a very simple nanomachine design with very little chemical energy consumption.
“We do not develop DNA robots for specific applications: our laboratory focuses on discovering the engineering fundamentals that allow the development of general-purpose DNA robots,” says Qian.
“However,” he adds, “I hope that researchers can use these principles for interesting applications, such as using a DNA robot to synthesize a therapeutic chemical from its components in an artificial molecular factory, administering a drug only when a specific signal is activated in the cell or bloodstream. , or even to classify disposable molecular components for recycling. ”
Bibliographic reference: Anupama J. Thubagere, Lulu Qian et al. “Charge-sorting DNA robot”.
Science, September 14, 2017.http: //www.agenciasinc.es/Noticias/Un-robot-de-ADN-ordena-moleculas-pasito-a-pasito
Source video: Veritasium