Using edible materials to make a robot, the size and shape of a capsule is about the same, such a robot can eat? If you can eat it, what do you expect from it? Q Bullet teeth, oily and not greasy, inlet ready?? Wait, it doesn’t seem to be quite the human with the robot. Should be: heat automatic stretching, can be controlled by magnets, into the body will not only dance like a dance sugar, but also the misswallowed battery out!
At the 2016 International Conference on Robotics and Automation, there was a blockbuster for such an edible capsule robot.
Four years later, a team of researchers at Johannes Keplinz University in Austria also invented an “edible” robot.
The robot was made using a universal biogel based on the food-grade material gelatin.
The little-looking robot is also a bit humble – not only can it be eaten by people, but it can also be eaten by microbes in the sewage within a few hours.
In a paper entitled Resilienct yet fully fulleielatin-based biogels for soft robots and electronics (an elastic, fully degradable gelatin-based biogel used in the manufacture of electronic products such as software robots), the team details the robot and the magic material behind it.
New materials based on gelatin
In the paper, the researchers opened up:
Materials drive technological progress.
Currently, the organisms used in software robots and stretchable electronic devices are mainly biodegradable and biocompatible elastic materials, with a range of characteristics, such as: excellent mechanical properties, tunability, changeability, self-healing.
But the team believes that the material is not durable in the environment and does not reflect all the characteristics in one product or platform.
So the research team developed a versatile gelatin-based biogel. The material is highly elastic, self-adhesive, quick-healing, easy to replicate and scale, and completely degraded during treatment.
It is understood that this material is made up entirely of natural ingredients and food-grade safety materials, including:
Gelatin: can be completely degraded by the human body;
Citric acid: can prevent bacteria from growing;
Glycerin: Prevents bacterial growth and dehydration.
It is worth mentioning here the researchers’ selection process for basic ingredients.
According to the paper, the researchers compared a variety of polyester fiber and hydrogel components to identify an ingredient, mainly taking into account factors such as duration, mechanical properties, cost, processability, composability and degradation.
After comparison, the researchers finally selected gelatin (the bottom row of the table above).
The reason for the use of gelatin is that gelatin-based biogels are easy to obtain, do not need to be synthesized, can be added water-soluble additives. At the same time, because of the rapid degradation rate, not only environmentally friendly, even edible.
In fact, many people are no strangers to gelatin, from film, food, cosmetics to medicine, gelatin is everywhere. Gelatin has also been used in areas such as drug delivery and bone tissue engineering, such as 3D-printed organs and manufacturing robots.
To test the degradation, the team immersed the biogel tablets in deionized water at 23 degrees C and found that the biogel tablets would dissolve within a few hours (shown in Figure c below).
That’s why the team says the biogel is ideal for temporary installation and frequent updates, and when triggered, it breaks down within a few days and benefits from transient devices.
In addition, the team measured the full oxygen demand decomposition of biogels by using the bio-oxygen demand (BOD) of microorganisms in wastewater. The results show that 60% of organic compounds can be removed in 10 days (as shown in figure d below). So, based on the biogel developed by the team, researchers may be able to open up new avenues for biodegradable applications in water and in vivo.
Robots that cycle more than 330,000 times
In their paper, the team wrote:
This biogel is a step closer to building durable, sustainable software robots and electronic systems.
So what is a robot based on the above materials?
In appearance, the researchers were inspired by the elephant. Of course, not only is it elephant-like, but the robot’s elephant nose can also catch objects thanks to the integrated feedback and control sensors.
On the basis of biogels, the researchers combine natural derivatives such as cellulose and zinc.
Among them, cellulose is a common structural polysaccharide that is used as an outer skeleton of a flexible pneumatic biogel actuator in dynamic environments (section a above). Combining biogels with structured zinc electrodes allows the electronic skin (the new wearable flexible bionic haptic sensor) to completely degrade (part b above).
As a result, the entire system is biodegradable, from the original robot to the extendable electronic device. The research team also said:
This paves the way for future biomedical devices that simulate our own skin.
As mentioned above, biogels degrade completely when treated in wastewater, so some may question the robot’s mechanical properties.
With this in mind, the team also explained that biogels maintain their mechanical properties under environmental conditions for more than a year;
In addition, the team says the robot could be used in the future to deliver drugs to animals.
Martin Kaltenbrunner, one of the co-authors of the paper, asked:
Can we simultaneously develop a material that is very reliable for use and completely degraded when triggered?
Now it seems that the team has given the answer with its results.
Last but last not, answer an important question, can robots eat?
According to the team, although the biogel is edible, the robot’s original electronics and sensors are not yet available.
In fact, as early as 2017, the Intelligent Systems Laboratory of the Federal Institute of Technology in Lausanne has introduced an edible robot that looks like gummies and is fully edible and made from gelatin.
This robot can be mixed with nutrients, drugs and other ingredients, digested and metabolized by the human body, we can equate the robot with a food.
So this robot, called Medical Black Tech, can be eaten by us, and in terms of safety, IEEE Spectrum editor Evan Ackerman’s words give us a heart-stopping pill:
As far as we know, no edible robot has crawled out of people’s stomachs after being eaten.