Researchers at MIT have designed a gastrointestinal pressure sensor that is inspired by the ancient Incan practice of quipu, which involves adding knots to a length of string to record information.
The knotted string approach has been put to good use by these MIT researchers, who discovered that introducing knots into an inexpensive gastrointestinal pressure sensor they had developed increased its sensitivity.
Gastrointestinal motility issues underlie various GI conditions, but current techniques to measure gastrointestinal pressure are cumbersome and expensive. This new approach provides an inexpensive sensor that can be sterilized through autoclaving, or even deployed as a single-use, disposable sensor.
Gastric motility, during which the gastrointestinal muscles push ingested food through the tract, is hugely important in normal GI function, and if this process becomes dysregulated it can contribute to a variety of disorders, including constipation, acid reflux, and irritable bowel syndrome. At present, diagnosing or assessing a gastric motility issue is typically performed using high-resolution manometry, but the equipment required is expensive and has various downsides.
“High-resolution manometry can measure the pressure and speed with which the contractile waves are traveling, but those systems are fairly expensive, in the tens of thousands of dollars range, and they require maintenance and sterilization between patients,” said Giovanni Traverso, an MIT researcher involved in the study.
In an effort to design a simple and inexpensive alternative, these researchers used a simple tube that is filled with a non-toxic liquid metal called gallium-indium eutectic. The sealed tube can measure changes in pressure but was not sensitive enough to measure the subtle pressure differences in the GI tract. In a simple evolution of the technology, the researchers began to experiment by tying various types of knots in the tube, and observed that the sensitivity of the measurements increased.
The researchers attribute this change in sensitivity to the increasingly elongated cross section of the knotted tube and the stacked layers of the tube within the knots themselves, which both helped to increase pressure sensitivity. The new sensors are inexpensive, and could provide an excellent alternative to expensive systems, which would be particularly useful in low-resource regions of the world.
“They’re super quick to build and super cheap,” said Kewang Nan, another researcher involved in the study. “Another motivation for making GI manometers cheap and disposable is to promote decentralized diagnosis. Here, being cheap facilitates accessibility by bringing down cost, and being disposable further helps public acceptance by eliminating cost of maintenance and reducing complication during use.”
Check out an MIT video about the technology:
Study in Nature Biomedical Engineering: Low-cost gastrointestinal manometry via silicone–liquid-metal pressure transducers resembling a quipu