A Logical Breakthrough in Medicine: The Nano-Robots of Dr. Ido Bachelet

In 2012, Dr. Ido Bachelet and his Harvard research partner Dr. Shawn Douglas demonstrated how a nano-fabrication technique known as “DNA origami” can produce a structure capable of targeting specific tissues, and opening up to activate sequestered payloads in response to specific molecular signals.  Now, in an article published in Nature Nanotechnology, Bachelet has gone a step further, creating nano-scale robots that coordinate and work as a team to carry out complex operations inside a living animal.

Bachelet, an expert in pharmacology and experimental therapeutics who joined the BINA faculty after completing post-doctoral research at both Harvard and MIT, has long been interested in “swarm behavior” – the de-centralized dynamic in which relatively simple organisms, capable of a limited repertoire of actions, cooperate to produce results that could not have been achieved by one individual. Based on this concept, Bachelet has designed an injectable “swarm” of nano-robots that interact, and respond to environmental cues by either triggering or inhibiting specific outcomes. 

Bachelet’s work represents a significant step toward the implementation of biological computing in living organisms.

Atomic force microscope images of robot architectures

“In this work, we’ve designed robots that circulate inside a living organism and make decisions on the activation or deactivation of a payload – such as a drug, growth factor, or enzyme – only when specific conditions are met,” Bachelet says, adding that billions of such robots can be suspended in a single drop of injected saline.  “The robots mimic logic gates, receiving their ‘input’ from the animal’s biochemistry and writing their ‘output’ in the form of a payload acting on target cells.” Bachelet’s robots also relay their output as inputs to other robots, achieving more complex functions. Thus, it could be possible in the future to load the robots with a repertoire of drugs and let them decide, based on what they find in the patient, which combination of drugs to activate.

In addition to their advantages for medical diagnostics and drug delivery, Bachelet says, nano-robots may someday revolutionize medical surgery. “Nano-robots can be programmed to target the interface between target and background tissue,” he says.  “This means that, once the robot arrives and binds to the site, it can activate its cargo – say, an enzyme – severing links between individual cells.  This is like a surgical scalpel – but unlike those used by surgeons, this scalpel can make an incision with molecular-level accuracy.”

Bachelet’s work represents the first time that anyone has demonstrated the efficacy of a nano-robot-based logic system inside a living animal. But his study – which used the Blaberus discoidalis cockroach as a model system – begs the question: just how long will it take before swarms of nano-robots can be put to work battling human disease?

While the results are encouraging, Bachelet points out that a great deal of work will be necessary before nano-robotics become standard medical procedure, or even reaches clinical trial.  Among the various challenges that remain, Bachelet’s group is currently focusing on making the robots invisible to the mammalian immune system so they can remain stable in the blood for hours or days.

Ultimately, Bachelet says, medical progress depends on good science – and economics.

“Today, surgery is expensive, and is only available to patients who have access to specialized operating theaters and trained medical personnel,” he says.  “But the cost of fabricating a billion-strong team of medical nano-robots, and injecting it into the bloodstream to perform a specific procedure, is very low.  This could revolutionize the practice of medicine and save lives all over the world.”