A DNA nanorobot is programmed to pick up and sort molecules into predefined regions.
Imagine a robot that could help you tidy your home: roving about, sorting stray socks into the laundry and dirty dishes into the dishwasher. While such a practical helper may still be the stuff of science fiction, Caltech scientists have developed an autonomous molecular machine that can perform similar tasks—at the nanoscale. This “robot,” made of a single strand of DNA, can autonomously “walk” around a surface, pick up certain molecules and drop them off in designated locations.
The work was done in the laboratory of Lulu Qian, assistant professor of bioengineering. It appears in a paper in the September 15 issue of Science.
“Just like electromechanical robots are sent off to faraway places, like Mars, we would like to send molecular robots to minuscule places where humans can’t go, such as the bloodstream,” says Qian. “Our goal was to design and build a molecular robot that could perform a sophisticated nanomechanical task: cargo sorting.”
How to Build a Molecular Robot
Led by former graduate student Anupama Thubagere (PhD ’17), the researchers constructed three basic building blocks that could be used to assemble a DNA robot: a “leg” with two “feet” for walking, an “arm” and “hand” for picking up cargo, and a segment that can recognize a specific drop-off point and signal to the hand to release its cargo. Each of these components is made of just a few nucleotides within a single strand of DNA.
In principle, these modular building blocks could be assembled in many different ways to complete different tasks—a DNA robot with several hands and arms, for example, could be used to carry multiple molecules simultaneously.
In the work described in the Science paper, the Qian group built a robot that could explore a molecular surface, pick up two different molecules—a fluorescent yellow dye and a fluorescent pink dye—and then distribute them to two distinct regions on the surface. Using fluorescent molecules enabled the researchers to see if the molecules ended up in their intended locations. The robot successfully sorted six scattered molecules, three pink and three yellow, into their correct places in 24 hours. Adding more robots to the surface shortened the time it took to complete the task.
“Though we demonstrated a robot for this specific task, the same system design can be generalized to work with dozens of types of cargos at any arbitrary initial location on the surface,” says Thubagere. “One could also have multiple robots performing diverse sorting tasks in parallel.”
Design through DNA
The key to designing DNA machines is the fact that DNA has unique chemical and physical properties that are known and programmable. A single strand of DNA is made up of four different molecules called nucleotides—abbreviated A, G, C, and T—and arranged in a string called a sequence. These nucleotides bond in specific pairs: A with T, and G with C. When a single strand encounters a so-called reverse complementary strand—for example, CGATT and AATCG—the two strands zip together in the classic double helix shape.
A single strand containing the right nucleotides can force two partially zipped strands to unzip from each other. How quickly each zipping and unzipping event happens and how much energy it consumes can be estimated for any given DNA sequence, allowing researchers to control how fast the robot moves and how much energy it uses to perform a task. Additionally, the length of a single strand or two zipped strands can be calculated. Thus, the leg and foot of a DNA robot can be designed for a desired step size—in this case, 6 nanometers, which is about a hundred millionth of a human’s step size.
Using these chemical and physical principles, researchers can design not only robots but also “playgrounds,” such as molecular pegboards, to test them on. In the current work, the DNA robot moves around on a 58-nanometer-by-58-nanometer pegboard on which the pegs are made of single strands of DNA complementary to the robot’s leg and foot. The robot binds to a peg with its leg and one of its feet—the other foot floats freely. When random molecular fluctuations cause this free foot to encounter a nearby peg, it pulls the robot to the new peg and its other foot is freed. This process continues with the robot moving in a random direction at each step.
It may take a day for a robot to explore the entire board. Along the way, as the robot encounters cargo molecules tethered to pegs, it grabs them with its “hand” components and carries them around until it detects the signal of the drop-off point. The process is slow, but it allows for a very simple robot design that utilizes very little chemical energy.
“We don’t develop DNA robots for any specific applications. Our lab focuses on discovering the engineering principles that enable the development of general-purpose DNA robots,” says Qian. “However, it is my hope that other researchers could use these principles for exciting applications, such as using a DNA robot for synthesizing a therapeutic chemical from its constituent parts in an artificial molecular factory, delivering a drug only when a specific signal is given in bloodstreams or cells, or sorting molecular components in trash for recycling.”
Learn more:: Sorting Molecules with DNA Robots
The Latest on: DNA robots
- MARA project aims to use new DNA based nanotechnology to fight bacteriaon November 27, 2020 at 5:18 pm
Antibiotics are used to prevent and treat bacterial infections. They have played a major role in combating infectious diseases such as tuberculosis, pneumonia, typhoid fever, and meningitis in 20th ...
- Robot zaps airport viruses as pandemic travel picks upon November 27, 2020 at 9:26 am
A COVID-killing robot? It's being tested out as a way to sanitize surfaces, but it doesn't address airborne transfer of the bug.
- Amazon Has Over 81,000 Black Friday Deals This Year — Here Are the Best 67on November 27, 2020 at 1:38 am
Amazon dropped over 81,000 Black Friday deals, including sales on popular tech, electronics, smart home, beauty, and much more. There are also big discounts on hot holiday gifts like Apple AirPods, ...
- WinDays20 keynote will answer the question of whether robots or humans winon November 26, 2020 at 1:37 pm
The schedule of conference sessions is published – during three days the participants will be able to watch and listen to more than 60 sessions and panels in three tracks ...
- Robots taking jobs, but creating careerson November 26, 2020 at 8:52 am
The good news is, whatever they end up doing is likely to be more fulfilling than the mundane, repetitive tasks that the robots have taken over from them. The bad news is there will be a period when ...
- Airport introduces germ killing roboton November 26, 2020 at 8:00 am
An airport in the US is employing a robot that kills germs in a bid to help stop the spread of coronavirus. San Antonio International Texas has introduced the $125,000 (£94,000) device, known as ...
- Virus-killing robot zaps airport viruses as pandemic travel picks upon November 25, 2020 at 11:00 am
As air travel gains some steam and coronavirus-related shutdowns return in pockets of the country, one of the latest iterations of virus-fighting tech at the airport is a germ-zapping robot at San ...
- This Fantastic Russian Cyberpunk Farm Video Has A Nice Twist Ending And Some Wonderfully Crappy Robotson November 23, 2020 at 8:34 am
I didn’t realize it, but there’s a name for the wonderfully ramshackle mash-up of clunky but high-tech machines, half-assery, and a certain kind of genial safety-adverse Russianness: Birchpunk. A ...
- Warehouse robots upgraded to make packing decisions 350 times fasteron November 20, 2020 at 2:20 am
Robotic arms for packing boxes in warehouses work out which path to take more than 350 times faster when using a neural network that predicts how quickly they can safely transport items ...
- Automation Is The App, UiPath Powers Up Low-Code Robotson November 18, 2020 at 7:51 pm
All of that being said, as we drive Robotic Process Automation (RPA) software robots into more roles, we do want to be able to build them using faster low-code controls that perform an increasing ...
via Google News and Bing News