An ongiong research, in the field of medical science, pertains to the development of multi-purpose edible electronics that would allow scientists to expedite the diagnosis and treatment of diseases as well as drug testing. In the past, we have talked about 3D-printed ingestible biosensors, in the form of electronic gelatin, that could help gather information about the various biomedical processes occurring inside the patient’s body. Researchers, at Carnegie Mellon University, are currently working to create digestible electronic “pills”, which could be powered safely by the natural juices present in our digestive tracts.
The concept of edible biomedical sensors has been around since the 1970s, with the early prototypes used for measuring temperature and other specific biomarkers. Over the years, technological advancements have led to the development of complicated electronic devices, which, although more efficient, often require surgical implantation, and also contain circuits and batteries that are not entirely digestible. For instance, we have sensors that can study the extent to which a particular drug is absorbed by our body as well as advanced cameras that closely examine the gastrointestinal tract before surgeries. Christopher Bettinger, a biomedical engineering and materials science professor at the university and a member of the research team, said:
The primary risk is the intrinsic toxicity of these materials. For example, if the battery gets mechanically lodged in the gastrointestinal tract — but that’s a known risk. In fact, there is very little unknown risk in these kinds of devices. The breakfast you ate this morning is only in your GI tract for about 20 hours–all you need is a battery that can do its job for 20 hours and then, if anything happens, it can just degrade away.
In the new study, recently published in the journal Trends in Biotechnology, the researchers are looking for ways to develop edible electronics, featuring silicon circuitry wrapped with biodegradable hydrogel that is not only safe to consume but also capable of squeezing through narrow openings without getting stuck. Upon interaction with the body, the silicon can easily turn into silicic acid, which is actually good for our health. Similar devices, at present, possess regular, off-the-shelf batteries, like the kind found inside a watch. Instead, the team is trying to create a battery that can be driven by the body’s natural liquids. Bettinger explanined:
If you really want to use these in a clinical setting, we think silicon is pretty good. I think a lot of people hand-wave powering these devices through external RF, but bodies are a pretty good Faraday cage.
The scientists have already built a prototype of this battery using melanin, the pigment responsible for giving hair, skin and eyes their color, as the cathode and an anode made of magnesium oxide, a mineral that is found in abundance inside our body. The electrolyte, in this case, is the gastric acid, which in turn allows the flow of current. During laboratory testing, the specially-engineered battery consistently produced power of up to 5 milliwatts, for a period of around 20 hours. According to the team, electronic devices, based on such technology, can dissolve in water within 2 or 3 months of consumption. Bettinger added:
… there’s already more melanin in a serving of squid-ink pasta than will be in our batteries. We think we can go to FDA and say, ‘here’s a battery compound of things that are already in our bodies, plus water’.
Furthermore, the scientists are developing a technology to 3D-print these “smart pills”, at low costs. The team said:
If we can engineer devices that get the most mileage out of existing drugs, then that is a very attractive value proposition. I believe these devices can be tested in patients within the next five to 10 years.
Source: Trends in Biotechnology