A tiny electronic sensor that can be swallowed like a pill may soon provide one of the most accurate ways to measure body temperature.
Engineers at the Massachusetts Institute of Technology (MIT) have developed a miniature device that continuously monitors temperature from inside the digestive tract, potentially helping doctors detect infections earlier and better manage many health conditions.
Most people measure their temperature using oral, ear, or forehead thermometers. While these methods are convenient, they do not always reflect the body’s true core temperature.
Core temperature, which represents the temperature deep inside the body, can provide a more accurate picture of a person’s health and may reveal signs of illness sooner.
The new sensor is remarkably small. It measures just 6 millimeters across and 4 millimeters high, making it roughly the size of a tiny blueberry.
Existing ingestible temperature sensors are usually as large as a multivitamin tablet, making them harder to swallow and slightly increasing the risk of becoming stuck in the digestive tract.
The MIT researchers designed the sensor with safety and comfort in mind. By making it much smaller, they reduced the chances of blockage while making it easier for people to swallow.
Creating such a tiny device was not easy. The team had to shrink all of its main components, including the temperature sensor, communication antenna, and battery.
They built a custom electronic circuit that fits onto a silicon chip only one square millimeter in size.
The device is also highly energy efficient. It uses only about 10 nanowatts of power, allowing it to run on a very small coin-shaped battery. The sensor can measure temperature with impressive precision, detecting changes as small as 0.01 degrees Celsius.
To save even more energy, the sensor uses a communication method called backscattering. Instead of generating its own powerful radio signals, the sensor relies on an external antenna placed within about one to two feet of the body.
The external antenna sends out radio waves, and the sensor modifies these waves and sends them back. By analyzing the returning signals, the external antenna can determine the person’s core temperature.
The sensor records and transmits a temperature reading every second, allowing for continuous monitoring.
Researchers believe the technology could have many uses. It may help doctors quickly identify infections in people whose immune systems are weakened by chemotherapy or medications. It could also monitor patients during surgery, as anesthesia can interfere with the body’s ability to regulate temperature and increase the risk of hypothermia.
Beyond hospitals, the sensor could potentially be used at home. It may help parents monitor fevers in children, assist women in tracking ovulation through core body temperature changes, and monitor athletes, soldiers, or others who work in extreme temperatures.
Animal studies have already shown that the sensor can accurately measure and transmit temperature information, even while subjects are awake and moving. The researchers are now developing versions that can also monitor other vital signs, such as heart rate, and hope to begin human clinical trials in the next few years.
If successful, this tiny “blueberry” sensor could one day change how people monitor their health, offering continuous and highly accurate temperature tracking with nothing more than a swallow.
