A team of researchers from the University of Arizona has developed a new class of ultra-thin wireless devices that grows to the surface of the bone and could someday help physicians monitor bone health and healing over long periods.
Called osseosurface electronics, these devices feature soft mechanics, ultra-thin form factor, and miniaturized multimodal biointerfaces comprised of sensors and optoelectronics directly adhered to the surface of the bone. The array of sensors is packed into a flexible package as thin as a sheet of paper and roughly the size of a penny. This means it can conform to the curvature of the bone, forming a tight interface.
The ‘Computer on the Bone’ can wirelessly transmit data about the bones out to a smartphone or other device. They also do not need a battery; instead use a power casting and communication method called near-field communication (NFC), which is also used in smartphones for contactless pay.
To keep it attached to the bones for a long period of time, the team has developed an adhesive that contains calcium particles with an atomic structure similar to bone cells, which is used to secure osseosurface electronics to the bone. “The bone basically thinks the device is part of it and grows to the sensor itself,” said the study co-senior author Philipp Gutruf, an assistant professor of biomedical engineering. “This allows it to form a permanent bond to the bone and take measurements over long periods of time.”
A doctor could attach the device to a broken or fractured bone to monitor the healing process. This could be particularly helpful in patients with conditions such as osteoporosis, since they frequently suffer refractures. Knowing how quickly and how well the bone is healing could also inform clinical treatment decisions, such as when to remove temporary hardware like plates, rods, or screws.
The team has tested the battery-free device in animals, showing they can be used in freely-moving small animal models and in deep tissue in large animal models. The real-time data can be read with a smartphone highlighting suitable characteristics for exploratory research and utility as a diagnostic and therapeutic platform.
Researchers believe that close bone monitoring would allow physicians to make more informed decisions about drug dosage levels.
“Being able to monitor the health of the musculoskeletal system is super important,” said Gutruf, who is also a member of the university’s BIO5 Institute. “With this interface, you basically have a computer on the bone. This technology platform allows us to create investigative tools for scientists to discover how the musculoskeletal system works and to use the information gathered to benefit recovery and therapy.”