Tiny swallowed devices have already shown their effectiveness as a more advanced way to deliver drugs inside the body and perform invasive procedures such as colonoscopy. The main problem of such devices is still the power supply.
Researchers at the Massachusetts Institute of Technology have developed a safe power source that uses stomach acid as an electrolyte. It will become part of already developed drug delivery systems that act inside the body for several weeks.
The idea of using gastric juice as an electrolyte is easy to explain, since the electrolyte base of most batteries is acid. As an experiment, the scientists attached zinc and copper electrodes to the outside of a small swallowable capsule containing a thermal sensor and a 900 MHz transmitter.
Stomach acid appears to conduct electrical current well between the electrodes, making the device work. In the course of experiments carried out on pigs, it was possible to take temperature readings and transmit them wirelessly every 12 seconds at a distance of up to 2 m from the receiver.
The “journey” of the device inside the gastrointestinal tract lasted for about six days. After entering the small intestine, the acidity decreased, which led to a decrease in the efficiency of the device by about 1%, but this was quite enough for its long-term operation.
The device is 40 mm long and 12 mm wide. The energy received is sufficient to deliver the drugs wrapped in thin gold foil. As the researchers assure, in the future, as the system improves, its size will decrease.