MIT's Origami Bots and the Promise of Nanotechnology
By Kendall Costello
The pain had started two weeks before. The stomach-jarring, nausea-inducing agony. The never-ending waves of abdominal contractions. My stomach seemed to be at war with itself, a war that left me doubled over, gasping for breath. The events which followed are a blur: the trip to the hospital, the thirty-six hour fast, the ultrasound which finally led to a diagnosis: appendicitis.
Surgery immediately ensued. Afterwards, I remembered looking at my scar, an inch-wide purple dagger slashed across my lower right abdomen. As an eight-year-old, I thought it was pretty large and cool-looking, something I could show off to my fellow peers to prove how tough I was.
Fast-forward five years. As a teenager, I remember gazing in awe at my friend's stomach - she had just gotten back from her appendectomy. Miraculously, there was only one tiny incision point inside her belly button. I remember thinking: if an inch-wide scar could be reduced to a mere incision point in five years, what else could medical innovation uncover? Could invasive surgery become completely unnecessary?
And indeed, that time has come.
This past spring, scientists at the Massachusetts Institute of Technology (MIT), the Tokyo Institute of Technology, and the University of Sheffield designed a miniature ingestible robot that unfolds inside a patient to act as a micro-surgeon, performing rudimentary non-invasive operating procedures. The origami robot, which is made out of a durable, dry, pig-intestine-derived material, is wrapped into a dissolvable pill capsule and uses external magnetic fields to steer itself along the stomach wall, performing programmed operations such as stitching up internal wounds, delivering medicine, or removing accidentally swallowed objects.
While it may seem revolutionary, the concept of an ingestible origami surgical robot actually builds upon decades of academic work from Daniela Rus, a Professor in MIT’s Department of Electrical Engineering and Computer Science, and an even longer history in the field of nanotechnology, whereby nanosurgical robots were an idealized fantasy for the forefathers of the field. To better understand the magnitude of such an invention, it is best to go back to when the concept was initially proposed.
A Brief History of Nanotechnology
Most people believe the field of nanotechnology came to fruition with Richard Feynman’s 1959 famous lecture “There's Plenty of Room at the Bottom,” at the California Institute of Technology during the American Physical Society’s annual meeting. In the speech, Feynman suggested a new way to manipulate atoms and engineer synthetic compounds. Indeed, he even suggested how these developments could drive technological innovation, such as the design of denser computer circuitry boards or more powerful microscopes. He even hypothesized that one day people would be “swallowing the doctor,” a reference to the future of noninvasive surgery with surgical nanorobots.
Feynman’s speech went largely unnoticed until the 1990’s, when it was rediscovered and used to popularize the field of nanotechnology. With its growing popularity, the speech influenced other bright thinkers of the time to consider a new world involving nanoparticles and their constructive might. Kim Eric Drexler for instance, published his 1986 novel Engines of Creation: The Coming Era of Nanotechnology which theorized the ability for artificial machines to self-replicate via computer control. Additionally, since these machines would be programmable, Drexler envisioned a future where billions of these nano-factories could effectively allow the Library of Congress to fit on a sugar-cube sized chip.
With the publication of Drexler’s book, the previously esoteric field of nanotechnology was finally open to the general population. However, not everyone was pleased with the perilous ramifications of such developments, particularly considering that what man designs could potentially turn on the rest of society. Such a hypothetical scenario was proposed in Michael Crichton’s bestseller novel, Prey, which warns against the dangers of algorithmic swarms of self-sustaining malignant nanoparticles.
What Nanotech Looks Like Today
For starters, nanotechnology is the science of engineering at the nanometer level, the scale at which it is practical to manipulate individual atoms. One of the recent developments of nanotechnology involves the creation of nanorobots. Because these machines operate at an atomic level, they must take into account different physical forces which are usually negligible at the macroscopic scale, such as electromagnetic interactions between subatomic particles.
Recent inventions reflect just how versatile the field of nanotechnology is. From ant-like automatons with organizational capabilities to bacteria-powered robots with navigational apparatus, nanotech has come a long way since its inception. One notable development is the formation of three-dimensional nanomachines from DNA, which was accomplished at Ohio State University. This creation of DNA origami resulted from the combined manipulation of natural and synthetic DNA molecules. By alternating single-stranded DNA, which provided more flexibility, with double-stranded DNA, which allowed for more stability, scientists could assemble rudimentary 3D origami machines capable of biomarker detection.
Another notable development was the use of magnetism to generate nanomachine movement, which was accomplished by a group of researchers at the University of Twente in the Netherlands and the German University in Cairo. Inspired by the movement of sperm, scientists designed a 332 micron-long flagellated robot which, when subjected to an oscillating electromagnetic field the strength of a refrigerator magnet, produces a magnetic torque which causes its flagellum to oscillate as well. These micro-robotic movements could then be steered towards a certain destination by subsequent manipulations of nearby magnetic field lines.
Together, these prior experiments with DNA origami and sperm-inspired locomotion laid the stage for MIT’s recently-developed ingestible robot. At the 2015 International Conference on Robotics and Automation, MIT researchers proposed its initial prototype, whose minimalistic design consisted of a small magnet affixed to a flat plastic sheet. The sheet, when heated, could expand into its specified three-dimensional insect-like shape and then move in accordance with the external magnetic field in a “stick-slip” manner. In other words, its appendages could stick to nearby surfaces with the aid of friction and then unstick, or slip free, to allow the prototype to maneuver through its environment.
Such mechanisms influenced the development of its successor. As stick-slip can only work when the robots are extremely stiff, the researchers compensated for the new bio-material’s increased flexibility by including fewer slits in the design. Furthermore, because of the fluid-like environment of the stomach, MIT researchers included a fin on the robot to help it propel itself forward. At the center of the robot is the magnet that interacts with the changing electromagnetic fields to produce movement. This movement is caused by quick and long rotations, depending on whether the nanorobot is spinning in place or pivoting around one appendage.
One practical - though likely unexpected - application for the origami robot is to remove batteries people accidentally swallow. Each year, more than 2,000 people accidentally swallow a button battery, which can sometimes induce an electric current that burns surrounding tissue. As Bradley Nelson, a professor of robotics at the Swiss Federal Institute of Technology Zurich, mentioned regarding the idea of origami robots, “this concept is both highly creative and highly practical, and it addresses a clinical need in an elegant way.” This elegant treatment is a first step in the space of non-invasive surgery as it introduces a foreign, operable tool into the human body in order to resolve a medical complication for the patient. Furthermore, one can even imagine a future where this technology will apply to scenarios as varied as recovering swallowed batteries to stitching up internal surgical wounds and delivering medicine to particular parts of the body. The future of ingestible robot pills could eventually even include the promise of non-invasive appendectomies, a prospect which would have astounded my eight-year-old self.
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