Scientists build 'DNA robots' that transport molecular cargo using 'arms' and 'feet'

Scientists build 'DNA robots' that transport molecular cargo using 'arms' and 'feet'

"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", said Professor Lulu Qian, one of the leaders of the study.

Caltech researchers have created a nanoscale biological robot from a single strand of DNA, which can carry and deliver molecular cargo according to an article published Thursday in the journal Science.

"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 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".

In principle, the robots themselves are not DNA strands designed as the double helix we all know from school but instead are made up of the components that make up their nucleotides.

DNA robots have been developed in the past, but the experiments represent the first time the machines have been shown to walk, sort and work together. Scientists made the robot in a way that they can transverse the molecular surface, and it can lift the two molecules like a fluorescent yellow dye and pink dye. On a special surface was located 3 pink and 3 yellow molecules, the robot had to sort them by color, vary the desired area.

If they add more robots the time for arranging the molecules on the surface will become less.

It works like this: Strands of DNA have unique chemical and physical properties determined by their nucleotides.

The DNA is composed of base nucleotides Adenine (A), Thymine (T), Cytosine (C) and Guanine (G) which are complementary to each other.

A single strand containing the right nucleotides can force two partially zipped strands to unzip from each other. How rapidly each zipping and unzipping event happens and how much energy it consumes can be predicted for any specified DNA sequence, allowing researchers to regulate how fast the robot travels and how much energy it consumes to do a task. It includes two "foot" domains joined by a leg strand and a "hand" domain at the end of an arm strand.

Nanobots are devices made from DNA that are so small they can be injected into the human bloodstream.

The technology could one day be used to transport molecules of many types throughout the body potentially transforming everything from drug delivery to how the body fights infections to how microscopic measurements are made. The DNA robot can move around the nanometre pegboard which is 58×58. The robot moves by attaching to one peg after another, and linking to its DNA.

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.

All this hopping might sound quick, but a single step between stones takes a rather lengthy 5 minutes, meaning that covering the entire surface takes a whole day. 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.