Flexible electronics have had a seismic impact on the world of wearables: body-contouring patches, devices with stretchable sensors, and implantable electronics of all kinds. But all share one impediment: integration with the human body. As wondrous as these pliable electronics are, they are still made of materials that have mechanical and biological properties that differ from those of the human body. Until now. Researchers at Texas A&M University have created biomaterial inks that simulate the characteristics of human skin, opening up new possibilities for 3D-printed electronics.

So what exactly is biomaterial ink? To create the new ink, researchers turned to a recently developed class of 2D nanomaterials that have a thin-layered structure and combined them with modified gelatin. The result is a flexible, highly conductive hydrogel that researchers liken to the composition of Jell-O. Texas A&M professor Dr. Akhilesh Gaharwar says, “This newly designed hydrogel ink is highly biocompatible and electrically conductive, paving the way for the next generation of wearable and implantable bioelectronics.”

How does the ink work with 3D printers? Similar to toothpaste or ketchup, the ink has shear-thinning properties that allow it to stay solid in a tube, but flow like liquid when that tube is squeezed. This trait makes it perfect for 3D printing. Moreover, the electrically conductive ink can be used to print a range of complex 3D circuits — and not just on a flat surface but in a variety of configurations. A&M researcher Kaivalya Deo explains, “These 3D-printed devices are extremely elastomeric and can be compressed, bent, or twisted without breaking [and] these devices are electronically active, enabling them to monitor dynamic human motion and paving the way for continuous motion monitoring.”

Where will we likely see this 3D ink in use? Researchers suspect that the emerging area of electronic tattoos is ripe for this new technology. Specifically, for patients with Parkinson’s disease; in theory, an e-tattoo would have the ability to monitor a patient’s movements, which in the case of people with Parkinson’s disease often includes tremors and slow, rigid body movements.