Researchers from Northwestern Medicine and Northwestern’s McCormick School of Engineering have created the world’s smallest wearable, battery-free sensor. The sensor is designed to measure exposure to light across multiple wavelengths spanning UV to visible light. It’s able to record up to three separate wavelengths of light at once.
The team says that the underlying physics and extensions of the platform give it a wide array of potential clinical applications. The device is solar powered and very robust, and said to be “virtually indestructible.” During a study where human participants wore the sensor, the sensor recorded multiple forms of light exposure during outdoor activities, even when the user was in the water.
The sensor was also used to monitor therapeutic UV light in clinical phototherapy booths used to treat psoriasis and atopic dermatitis. It can also measure blue light therapy for infants born with jaundice. White light can also be measured as a way to treat seasonal effective order.
The sensor can separately and accurately monitor both UVA and UVB exposure for people at higher risk of melanoma. The team says that the sensor weighs as much as a raindrop and has a diameter smaller than an M&M candy while being about as thick as a credit card.
The workings of the sensor are completely sealed in a thin layer of transparent plastic making it robust, and it has no switches or interfaces to wear out. Readings from the sensor are passed wirelessly to a mobile phone. The team believes the sensor will last forever. So far attempts to break it have failed, it has been boiled and placed in a simulated washing machine and still worked.