Giovanni Traverso keeps a tiny capsule on his desk—no bigger than a blueberry—that could one day quietly monitor the health of millions from within their own bodies. Developed by engineers at MIT in Cambridge, this minuscule ingestible sensor, just 6 millimeters in diameter, travels through the gastrointestinal tract sending real-time updates on core body temperature with astonishing precision: 0.01°C accuracy. Unlike traditional thermometers that measure under the tongue or on the forehead, this device captures the body’s true internal climate, offering a far more reliable signal of infection, fever risk, or even fertility windows.
Core temperature is a vital sign, yet one that’s been surprisingly hard to track continuously and safely. Existing ingestible sensors, often the size of a multivitamin, carry risks of obstruction and are difficult to swallow—barriers that have limited their use. The MIT team, led by Traverso, MIT postdoctoral researcher Saransh Sharma, and Provost Anantha Chandrakasan, set out to redesign every component from the ground up. They engineered a custom silicon chip just 1 square millimeter in size, powered by a mere 10 nanowatts—so little energy that a 1.55-volt coin cell battery, thinner than a pencil lead, can keep it running. This dramatic reduction in power demand was achieved through an innovative oscillator that uses leakage current, whose frequency shifts with temperature.
Even more clever is how the sensor communicates. Instead of relying on power-hungry transmitters, it uses backscattering: a tiny internal antenna modulates ultra-high-frequency radio waves sent from an external device nearby, reflecting them back with temperature data encoded in the signal. This external antenna, placed within 30 to 60 centimeters of the patient, does most of the heavy lifting, slashing the sensor’s energy needs and allowing it to stay small and safe. The result? A capsule that transmits a temperature reading every second, continuously, as it moves through the digestive system.
The implications extend far beyond convenience. For immunocompromised patients—such as those undergoing chemotherapy—early detection of a rising core temperature could mean the difference between a mild infection and a life-threatening sepsis episode. The device could also transform fertility tracking, where precise temperature shifts mark ovulation, or improve safety during anesthesia, when body temperature can dangerously fluctuate. "A sensor like this gives us the ability to monitor infections and identify them early," says Traverso, whose dual roles as an MIT engineer and gastroenterologist at Brigham and Women’s Hospital ground the work in real clinical need.
Now that the prototype has proven its accuracy and feasibility, the team is looking ahead to human trials and eventual commercialization. In a world where health monitoring is increasingly personal and preventive, this blueberry-sized beacon could become a quiet guardian of our inner well-being.