Researchers from the MIT (Massachusetts Institute of Technology) of Boston have been inspired by the biological mechanisms of the pufferfish to create a certain type of pill for diagnostic and curative purposes that can be ingested normally but, as soon as it reaches the stomach, inflates until it reaches the size of a ping-pong ball (the pufferfish also expands on demand, but it does so to scare its enemies).
The new device can remain in the stomach for approximately one month, and is capable of monitoring a series of physiological parameters, or also illnesses like ulcers or tumors, thanks to a wireless micro-device inside the pill. When it expands, the “puffer-pill” (which until now has been tested on pigs) is too big to pass through the intestine, and it therefore enables the micro-sensor to work without problems in a difficult environment like the stomach for a period of four weeks. Once this time is up, the new pill is then easily expelled: all the patient has to do is drink a calcium solution to make the pill return to its original size, and thus it can continue its journey towards the intestine.
The pill – explain the US researchers in the scientific journal Nature Communication – can increase its volume up to 100 times in only 15 minutes. The bioengineers made the pill using two types of biogel: a highly-resistant protective biogel, on the surface, made of a nano-crystalline structure, and a sodium polyacrylate biogel, on the inside, which absorbs the substances found in the stomach and is also ideal for holding the micro-sensor (there are many different kinds of micro-sensors commercially available).
The new pill was studied under various conditions in order to reproduce the thousands of strains that stomachs are exposed to every day. After numerous tests it demonstrated its resistance and perfect ability to transmit information on the temperature and bacterial population found in the stomach. If there was a micro-video camera instead of the sensor – explain the authors – the new pill would also probably be able to check the development of lesions, such as neoplastic lesions, with considerable accuracy. Furthermore, in the future the same type of pill could become the basis for “balloons” that help obese people to lose weight and other devices to be ingested for various biomedical purposes.