PFI-TT: Noninvasive, compact, internal body thermometer

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project addresses the need for a sensor that can measure temperature inside the body several centimeters under the skin, for example the temperature of the heart or the brain. Internal body temperature is synchronized with sleep, and if body temperature is out of phase with the circadian cycle, relatively simple external stimuli can be applied to improve sleep.

Similar arguments can be made for other diseases of contemporary society, such as obesity, fertility, and depression, and can be expanded beyond wellness to clinical applications such as neo-natal care and heat treatment of cancers. The value proposition is in enabling non-invasive, wearable, internal body temperature measurements with the highest accuracy and reliability on the market.

The commercial potential of the proposed device is very large: 60 million US adults report frequent difficulty sleeping, with estimated indirect costs from insomnia due to loss of productivity as high as $60 billion annually. Once wearable sensor prototypes are developed, potential customers include medical device manufacturers and clinics.

The proposed project will produce a prototype of a low-cost, portable, internal body thermometer for personal wellness applications. The thermometer is based on the fundamental principle of passive electromagnetic measurements made by a device placed on the skin and operating in the microwave frequency range. The major challenge is detecting very small power levels radiated from deep tissue layers as opposed to measurements on the skin.

The engineering challenge and intellectual merit lie in further developing the proof-of-principle hardware and algorithms to achieve a commercially viable device ready for marketing. Overcoming this challenge will result in specifications in terms of prototype temperature sensitivity, spatial resolution, battery life, robustness, and ease of use. Engineering challenges include designing an ultra-low noise receiver, implementing radio-frequency interference mitigation techniques, and designing flexible probe antennas conformal to the skin on different parts of the body, all with a focus on low-power compact implementations.

After leveraging off-the-shelf components in the first phase, specialized chips will later be designed. The goal is to demonstrate an inexpensive device that can ultimately be disposable. The device is intended for mobile and long-term monitoring applications, with a proven market potential.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.