Electronically Active Ink Image
Texas A&M University, Department of Biomedical Engineering

While flexible electronics have brought major innovation to wearable and implantable medical devices, their specific mechanical and biological properties have made them incompatible for integration into the human body. However, a recent study from Texas A&M University resulted in a new class of biomaterial inks capable of simulating the characteristics of highly conductive human tissue, similar to skin, which the team says holds huge potential for 3D printing more advanced wearable and implantable devices.

“The impact of this work is far-reaching in 3D printing,” Associate Professor of Biomedical Engineering Akhilesh Gaharwar said of the results. “This newly designed hydrogel ink is highly biocompatible and electrically conductive, paving the way for the next generation of wearable and implantable bioelectronics.”

The research team combined the chemically active molybdenum disulfide (MoS2) 2D nanomaterial class with altered gelatin to create a flexible hydrogel that is conducive to 3D printing. The 3D-printed ink is liquid-like when squeezed but solid while inside a tube due to its shear-thinning properties, which decrease in viscosity with increased force.

According to Kaivalya Deo, a biomedical engineering graduate student and the paper’s lead author, the 3D-printed devices’ elastomeric properties allow them to “be compressed, bent or twisted without breaking,” allowing them to withstand movements within the human body. He adds, “These devices are electronically active, enabling them to monitor dynamic human motion and paving the way for continuous motion monitoring.”

Printing with the new ink required a specialized, multi-headed 3D bioprinter, which was designed by the University’s Gaharwar Laboratory. The fully functional and customizable bioprinter runs on open-source tools and freeware, making it both cost-effective and usable by any researcher. Researchers can make customized, patient-specific bioelectronics with the new ink because it is not limited to planar designs and is capable of creating complex 3D circuits.

Using the 3D-printed ink, the Deo’s team successfully printed stretchable, electrically active electronic devices with extraordinary strain-sensing capabilities.

The discovery offers great potential for designing microelectronic component-integrated, stretchable sensors as well as creating customizable monitoring systems like 3D-printed electronic tattoos for monitoring patient movement.