In a study published in the journal Science, researchers at the California Institute of Technology designed a group of DNA robots with 'bodies', 'hands', 'arms', and 'feet', which worked together to find and collect fluorescent molecules.
"We call [them] DNA robots because they can also perform mechanical tasks, but at the nanometer scale. We would like to send molecular robots to miniscule places where humans can't go, such as the bloodstream." said Lulu Qian, who led the research with graduate student Anupama Thubagere.
The DNA robot, consists of 53 nucleotides, features an arm with a hand to carry cargo and a central leg with two feet that wander a DNA track studded with pegs of single-stranded DNA. The feet anchor to the track one at a time as they bind to complementary nucleotides in the pegs. When the robot encounters cargo—in this case, a fluorescent molecule covalently linked to a short single strand of DNA—it picks the cargo up and carries it until reaching a single strand of DNA on the track that’s designed to snatch the cargo from the robot.
The research team used two types of cargo, one bit of DNA with a yellow fluorescent dye and one with a pink fluorescent dye, to demonstrate the robot could sort the two. One robot working alone on a surface was able to sort six molecules of cargo in about a day. When the team used multiple robots at once, they were able to speed up the process.
“What’s novel about this system is that it has a design that allows for an army of robots to operate independently,” comments John H. Reif, an expert in DNA robots at Duke University. “The design of the whole system is incredibly elegant and simple.”
Applications in chemical synthesis and drug delivery exist, but they’re a long way off, Qian says. “The point of this work is toward understanding the engineering principles for building general-purpose DNA robots rather than how to use them for specific applications,” she says.
Read More: "A cargo sorting DNA robot", Science 2017, DOI: 10.1126/science.aan6558
