Could we build a synthetic digestive system for Vision to make him more human?

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: How to build a synthetic digestive system for Marvel’s Vision. Bonus: assessing the health status of five Avengers to determine how their health will fare as they age.

The folks at Marvel Studios aren’t the only ones who like to imagine What If…? Inspired by Marvel’s Vision, two scientists reviewed the current state of soft robotics to determine whether it would be possible to build an artificial digestive system for the synthezoid, describing their work a paper published earlier this year in the journal Superhero Science + Technology.  (It’s an open access journal published by TU Delft “that considers new research in the fields of science, technology, engineering and ethics motivated and presented using the superhero genre.”)

Hey, inquiring minds need to know! It’s not just a fun exercise in a more positive form of nerd-gassing, either. The authors note that humanity in general would benefit from advances in such systems, with applications in organ replacement and clinical treatments for patients with chronic digestive issues. 

Not to be outdone, researchers at the University of Queensland in Brisbane, Australia, published a paper in the special Christmas issue of the British Medical Journal (BMJ), examining the personal traits and health behaviors of five of Marvel’s Avengers, in order to assess the challenges this extraordinary cohort might experience as they age. The BMJ’s Christmas issue is typically more light-hearted in nature, although the journal maintains that the papers published therein still “adhere to the same high standards of novelty, methodological rigour, reporting transparency, and readability as apply in the regular issue.”

A vision of artificial digestion

(Some spoilers for Avengers: Age of Ultron and WandaVision below.)

Vision, as a synthezoid, notoriously does not eat. In Captain America: Civil War, for instance, he tries to make Wanda’s favorite dish, paprikash, pointing out that his culinary skills might not be up to snuff, since he has never consumed any kind of food. This point is re-iterated in the second episode of WandaVision. Instead of deriving energy from a metabolic process, Vision gets an almost endless supply of energy from the Mind Stone in his forehead.

But does the fact that Vision doesn’t eat mean he can’t? He would need an artificial digestive system to do so, per co-authors Falk J. Tauber (University of Freiberg) and Barry W. Fitzgerald (Eindhoven University of Technology).  In the MCU, the synthezoid was created using Helen Cho’s regeneration cradle in 2015’s Avengers: Age of Ultron, out of vibranium and the artificial tissue Simulacra. Then the Mind Stone was placed in his forehead to power Vision’s artificial brain. There are no scenes in the Marvel films (or even the comic books) specifically revealing a digestive system.

But the regeneration cradle successfully gave Vision a brain, eyes, and a tongue, so the technology should also be capable of creating other organs—like an esophagus, stomach, intestines, and rectum, all essential elements of the human digestive system. The authors also note that Vision gets impaled in Avengers: Infinity War and experiences intense pain (but no blood loss). So Vision must have some kind of nervous system with pain receptors. But he may lack a circulatory system, which is crucial in the human body for distributing nutrients to cells.

Lacking a regeneration chamber, Vibranium, or a Mind Stone, Tauber and Fitzgerald looked to the field of soft robotics for potential components of an artificial digestive system. For instance, a good candidate for an artificial esophagus is a soft robotic peristaltic pumping system (known by its acronym SBPP), developed by Tauber (then Esser) and several colleagues in 2017. A human esophagus (and intestines) move food along through the system via peristalsis: a series of circular muscular contractions that propagate along the tubular organs.

The SBPP’s pneumatic chambers are integrated into the tubular body of the inner conduit wall, per Tauber and Fitzgerald. So when those chambers expand, the inner diameter is reduced, much like a human esophagus (or intestines). So its possible to create an artificial peristaltic contraction wave that travels in one direction along the length of the soft robotic organ. Reversing the direction of those contractions would enable Vision to vomit up any food or liquid in case of, say, food poisoning.

Artificial stomachs have also been developed. The authors cite a human gastric simulator built in 2015 as one potential candidate, especially since it was designed to mimic and study digestion and the transport of food. The simulator consists of a cylindrical latex chamber with walls that can be contracted by rollers, mimicking the activity of the human stomach wall during digestion. Another artificial stomach (SoGut) uses an array of circular air chambers to generate contractions.  Combining the two technologies “might not allow Vision to feel butterflies in his stomach, but would certainly allow Vision to process and chemically digest [food],” the authors wrote.

For the intestines, it might be possible to stitch together several SBPP systems, although “the inner tubular geometry would need to be adapted to match the internal structure of the intestines,” per Tauber and Fitzgerald. Alternatively, one might use the Modular Endoscopy Simulation Apparatus (MESA) developed by Colorado University scientists for endoscopy training, which already has a fold-like inner tube geometry.

As for simulating the gut microbiome, organ-on-a-chip microfludic devices are capable of mimicking the conditions of the human digestive tract, “hosting living tissue and a microbial flora on non-living materials, which is essential for a functioning artificial intestinal wall,” the authors wrote. Finally, Vision would need an artificial rectum to dispel waste products. Once again, the SBPP could be used, this time as an artificial bowel outlet, since it can simulate the pressures needed for a functioning sphincter.

Those are just the most basic components; the human digestive system is extremely complex. One would need a micrifluidic network in the intestinal walls to ensure nutrient uptake and transport. This in turn would need to be connected to an artificial blood circulation system, which Vision currently seems to lack. What about digestive juices, or chemical and mechanical receptors and sensors, so Vision could experience hunger? It’s also not clear whether an artificial digestive system would provide sufficient energy for Vision’s basic bodily functions, never mind his superhero capabilities.

Even the soft robotic components described above are too large to fit inside Vision’s body, and would need to be miniaturized. So while we have a plausible blueprint for one day being able to build a fully functional artificial digestive system for Vision, we don’t have that capability just yet.

Superhero health checks

Back in October, we reported on a tongue-in-cheek study of the health risks on display in all 25 James Bond films: namely, infectious agents during his global travels, covering everything from foodborne pathogens to ticks and mites, hangovers and dehydration from all those martinis, parasites, and unsafe sex. In the same spirit, a group of Australian researchers decided to examine the health benefits and risks of the Avengers. The underlying assumption is that all superheroes will age, with some exceptions—like Thor, an actual Norse god who has lived for millennia—and the factors that influence whether an ordinary human remains healthy as one ages apply to them as well.

Naturally, this required watching all 24 Marvel films released between 2008 and 2021, beginning with the original Iron Man and ending with Black Widow. Five specific Avengers were chosen for the study—Iron Man, Hulk, Black Widow, Black Panther, and Spider-Man—”because they are well-known, demonstrate notable characteristics, are reasonably diverse, and are representative of the broader superhero population, with regard to age, sex, ethnicity, and superpowers,” the authors wrote. 

On the plus side, superheroes are known for regularly engaging in often strenuous physical activity and exercise, which are beneficial to healthy aging. Other positive attributes include psychological resilience, a sense of purpose, a “high degree of social cohesion and connectedness,” and a “positive or optimistic mindset.”

Only one of the five smokes or drinks (Tony Stark/Iron Man), and Black Panther is a vegetarian. Tony and T’Challa’s wealth, intelligence, and education are also beneficial factors. Factors working against our superheroes are exposure to loud noises (including interplanetary collisions and explosions), air pollution, and injuries sustained during all that strenuous crime-fighting activity.

Peter Parker/Spider-Man is the youngest of the five, and while being orphaned at a young age can cause physical and emotional issues, his nurturing relationship with Aunt May, and the positive male role models he found through the Avengers (especially Tony Stark) would mitigate that. He’s got spideriffic strength, flexibility, and agility, which reduces his risk of falling in old age. But staying up all night to fight crime in the neighborhood means he’s probably not getting enough sleep, which could have negative impacts as he ages.

Natasha Romanoff/Black Widow was abandoned as a child and trained as an assassin and spy. A childhood filled with abuse, neglect, and constant conflict increases her risk of physical and mental ailments later in life. She was also forcibly sterilized at a young age, and hence could develop osteoporosis and cardiovascular disease, not to mention dementia and depression.

As for Bruce Banner/Hulk—well, he already arguably suffers from tachycardia (i.e., a heart rate of 200 beats per minute) every time he gets so enraged he transforms into the Big Green Guy, so he’s vulnerable to cardiac arrhythmias. This increase his risk of stroke and dementia—especially since, by his own admission, “I’m always angry.”

The authors also note Hulk’s high body mass index (BMI) of around 120, which puts him in the “obese” range. (BMI is defined as the weight in kilograms divided by the square of the height in meters.) But we feel obliged to point out that BMI is widely recognized as a flawed, imperfect metric for assessing future health outcomes. And the big, bulging, muscles that let Hulk SMASH so effectively aren’t the same as carrying a lot of excess fat.

DOI: Superhero Science + Technology, 2021. 10.24413/SST.2021.2.5636  (About DOIs).

DOI: BMJ, 2021. 10.1136/bmj-2021-068001  (About DOIs).