Intestinal glucose levels are a major indicator of overall gastrointestinal health, and the current method of measuring them involves putting a catheter down the patient's throat. Soon, however, a swallowable "smart pill" could do the job much less intrusively.
Currently in development at the University of California-San Diego, the pill is essentially a combined biosensor and biofuel cell, housed within a 3D-printed polymer shell. Once ingested, it continuously measures glucose levels in the small intestine, plus it uses that same glucose as fuel.
At regular intervals, the pill wirelessly transmits its readings using an energy-efficient technique known as magnetic human body communication. In a nutshell, this involves sending ultra-low-power magnetic pulses through the patient's body tissue, which are detected and decoded via a receiver-coil-equipped device worn on the outside of the body.
In tests performed on pigs – which have a gastrointestinal tract similar to that of humans – the pill successfully monitored glucose levels in the small intestine for 14 hours. Within that period, it transmitted real-time data every five seconds for two to five hours, depending on the individual test. It was ultimately passed with the feces.
Before the pill can be used on humans, it needs to made a bit smaller – it's currently 2.6 cm long by 9 mm wide (1 by 0.4 in). Plans also call for more sensors to be added.
"Given that the gastrointestinal tract possesses dynamic changes of pH, temperature and oxygen concentrations, future work envisions the integration of additional sensing modalities to account for these differences," said nanoengineering graduate student Ernesto De La Paz Andres, co-first author of a paper on the research.
That paper was recently published in the journal Nature Communications. And as an interesting side note, scientists at Australia's RMIT University have already developed a "smart" gut pill of their own, which measures and transmits data on intestinal gas levels.
Source: UC San Diego
