An international team at Penn State led by [Larry Cheng] made a breakthrough in printing sensors directly on skin without heat. The breakthrough here is the development of a room-temperature sintering technique. Typical sintering of copper happens at 300 C, and can be further lowered to 100 C by adding nanoparticles. But even 100 C is too hot, since skin starts to burn at around 40 C.
You can obtain their journal article if you want the details, but basically their technique combines the ingredients in peelable face masks and eggshells. With this printed circuit is applied to the skin, the sintering process only requires a hair dryer on the cool setting, and results can bend and fold without breaking the connections. A hot shower will remove the circuit without damaging the circuit or your skin. [Larry] says the circuits can be recycled.
They are using these sensors to monitor temperature, humidity, blood oxygen levels, and heart performance indicators. They’ve even linked these various on-body sensors with a WiFi network for ease of monitoring. After reading this report, we’re left wondering, if the sensor is directly on your skin, can it be really called wearable?
We’ve written about printable inks before, but for printed circuit board applications. We can’t help but wonder if this technology would help solve some problems inherent in that technology, as well. Thanks to [Qes] for the tip.