dna robot

The robots are collectively performing a cargo-sorting task on a DNA origami surface / Illustration: Demin Liu

Scientists have built and tested a tiny walking robot that can pick up and carry objects even though it’s so small you can’t see it. 

The nanobot machine is made of just a single strand of DNA, and has arms and feet, being able to pick up, deliver and sort molecules. 

In the future, its creators hope similar nanobots will be used to transport medicines to individual diseased cells or help assemble hard-to-make chemical compounds. 

“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 Lulu Qian at the California Institute of Technology in Pasadena. 

“Our goal was to design and build a molecular robot that could perform a sophisticated nanomechanical task: cargo sorting.”

To test it, the nanobot was sent to explore a molecular surface, pick up two different fluorescent dye molecules coloured yellow and pink, and deposit them at specific target drop-off points. 

The robot successfully picked up six fluorescent dyes. three yellow, and three pink, and moved them one of two destinations within 24 hours. 

The researchers say they could boost the speed by adding an enzyme to give extra thrust or giving the robot a chemical motor.

Dr. Qian added: “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 robot.”

“However, it is my hope that other researchers could use these principles for exciting applications, such as using a DNA robot for synthesising 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.”

This is an exciting step for precision medicine, that will hopefully lead to more effective treatments in the future by using molecular robots to deliver a drug only to the cells that show signs of disease within the bloodstream.