University of Columbia developed < 0.1 cubic mm single chip made of standard metal oxide semiconductor (as small as dust mite or visible only under microscope) which can be Put in our body so that it circulates together with the red blood cells to monitor and map biological signals, support and enhance physiological functions, and treat diseases and other in vivo applications.
The chip can be implanted via a hypodermic needle to measure internal body temperature, blood pressure, glucose, etc…
Ultrasound is leveraged to both power and communicate with the device wireless ly. Ultrasonic wavelengths, are very small at a given frequency because the speed of sound is so much less than the speed of light as compare to RF hence fit the bill.
Device uses a piezoelectric transducer that acts as an “antenna” to communicate and power with the device wirelessly using ultrasound waves.
This model can be used in clinical applications, and remote Healthcare eventually approved for human use.
Link to Research