Tiny Microrobots Backflip Through The Colon To Deliver Drugs

The microrobot can be seen just to the right of the “U” on this penny. They're that tiny. Purdue University image/Georges Adam

Forget butterflies in your stomach – try backflipping microrobots. Engineering perhaps the most extravagant way to deliver drugs possible, scientists from Purdue University have created tiny microrobots that carry drugs through the colon by backflipping.

In a study published in the journal Micromachines, the engineers showed off their tiny robots tumbling through a live animal model in a fascinating video. Although unorthodox, the flipping mode of travel makes perfect sense – the inside of the colon is rough, uneven terrain, making mechanical travel through it difficult. By repeatedly flipping, the robots can traverse the peaks and valleys to deliver important drugs directly to their target.

Watch the robots make their way through a live mouse colon below.  

Live ultrasound footage shows a microrobot tumbling through a colon in vivo. Purdue University video/Elizabeth Niedert and Chenghao Bi

At just 0.8 mm long and 0.4 mm wide, the mini-robots are small enough to track their way through the body without you feeling a thing. In fact, they’re so small that they cannot even carry their own batteries – instead, the robots are powered and controlled by a rotating magnetic field. Carrying an important drug payload, the locomotion enables specific targeting of drugs that other mechanisms of delivery do not allow.

“When we apply a rotating external magnetic field to these robots, they rotate just like a car tire would to go over rough terrain,” said David Cappelleri, a Purdue associate professor of mechanical engineering, in a statement. “The magnetic field also safely penetrates different types of mediums, which is important for using these robots in the human body.”

The microrobots could tumble through a variety of terrain, shown in multiple in vitro (cells outside their normal biological context), in situ (the medium in its normal place but the organism is dead), and in vivo (living organisms) conditions. Although it's too early for human trials, the experiment was carried out in living mice, in which the robots were inserted through the rectum and made their way up through the colon of unconscious mice under complete control of the researchers.

This study is the first in vivo demonstration of a microscopic tumbling robot ever performed and shows that it could be possible to utilize them in drug delivery in humans in the future. Once steered to their destination, the robots released their contents slowly, showing promise for a precise drug vehicle that could be used in intestinal disease and more.

“We were able to get a nice, controlled release of the drug payload. This means that we could potentially steer the microrobot to a location in the body, leave it there, and then allow the drug to slowly come out. [B]ecause the microrobot has a polymer coating, the drug wouldn’t fall off before reaching a target location,” Luis Solorio, assistant professor of biomedical engineering at Purdue, added.

Leaving behind a minimal amount of damage to the tissue as the robot rolled through, the microbots appear to be safe for passage through the many tunnels of the human body. Furthermore, they are made of cheap biocompatible materials and can be produced relatively quickly.

Miniature robots are becoming increasingly prevalent in predictions of how future medicine may look, with tiny robots being used in everything from cleaning out blood vessels to combatting infection. Infusing technology with the biological may be an important step to improved healthcare, and the results of this study suggest they may be closer than you think.

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