3D motes for real-time wireless temperature sensing

A mote is a tiny piece of a substance, as with a mote of dust.  But in this piece, the mote is an implantable sensor, from electrical engineers at Columbia University, which monitors body temperature, with implications for tracking other vital signs.  “[Their] device volume is less than 0.1 mm3, comparable to a grain of table salt, improving biocompatibility by reducing foreign body rejection and tissue damage, allowing access to limited interstitial spaces, and interfering less with the physiological functions to be monitored. Implantation procedures reduce to injection, which can be made easier and less invasive. At the length scales of these mote devices (linear dimensions less than 600 μm), efficient coupling to radio-frequency or millimeter-wave electromagnetic energy is not possible because wavelengths are substantially larger than achievable antenna sizes. We instead use ultrasound, which attenuates in soft tissues on the scale of only ~0.5 to 1 dB/(cm·MHz). At ~8.3 MHz, a wavelength of only ~185 μm allows efficient coupling to an integrated piezoelectric transducer on the mote. Use of these motes in the context of ultrasound imaging also allows biogeographic locations for the motes to be determined.”  MORE

Image Credit:   Advances.sciencemag.org and Columbia University