Cornell researchers have developed microsensors that are tiny enough to fit 30,000 on one side of a penny. These microscopic sensors are equipped with an integrated circuit, solar cells and Micro LEDs that enable them to harness light for power and communication. The research was published in PNAS in April, titled “Microscopic Sensors Using Optical Wireless Integrated Circuits.”

The research team devised a platform for parallel production of their optical wireless integrated circuits (OWICs), microsensors the size of 100 µm. Researchers in the study focused on the light as a potential power source and communication medium.

(Image: Cornell University)

The researchers developed a complicated assembly method that involved more than 15 layers of photolithography, 30 different materials and more than 100 steps in order to transfer the LEDs to a wafer with the electrical components and integrate them.

Once the OWICs are freed from their substrate of silicon, they can be used to measure inputs like voltage and temperature in hard-to-reach environments, such as inside living tissue and microfluidic systems. For example, an OWIC rigged with a neural sensor would be able to noninvasively record nerve signals in the body and transmit its findings by blinking a coded signal via the LED.

As a proof of concept, the team successfully embedded an OWIC with a temperature sensor in brain tissue and wirelessly relayed the results. The researchers have launched their own company, OWiC Technologies, to commercialize the microsensors.