'Hybrid 3D Printing' Makes Soft, Wearable Electronics


Wearable electronic devices that aim to track and measure the body's movements must be able to flex and stretch with the body, yet integrating rigid electrical components on or within flexible skin-mimicking matrix materials can be challenging. A new hybrid 3D printing technique developed at the Wyss Institute at Harvard University  combines stretchable conductive inks and electronic components into durable wearable devices that move with the body and offer increased programmability. The stretchable conductive ink is made of thermoplastic polyurethane (TPU), a flexible plastic that is mixed with silver flakes. "With this technique, we can print the electronic sensor directly onto the material, digitally pick-and-place electronic components, and print the conductive interconnects that complete the electronic circuitry required to 'read' the sensor's data signal in one fell swoop," says Harvard engineer Alex Valentine.