Potential uses include printing electronic tattoos for medical tracking applications
Flexible electronics has enabled the design of sensors, actuators, microfluidics, and electronics on flexible, conformable, and/or stretchable sublayers for wearable, implantable, or ingestible applications. However, these devices have very different mechanical and biological properties compared to human tissues and therefore cannot be integrated into the human body.
A team of researchers from Texas A&M University has developed a new class of biomaterial inks that mimic the native characteristics of highly conductive human tissues, much like skin, which are essential for the ink to be used in 3D printing. .
This biomaterial ink harnesses a new class of 2D nanomaterials known as molybdenum disulfide (MoS2). The thin film structure of MoS2 contains defect centers to make it chemically active and, combined with modified gelatin to obtain a flexible hydrogel, comparable in structure to Jell-O.
“The impact of this work is far-reaching in 3D printing,” said Dr. Akhilesh Gaharwar, associate professor in the Department of Biomedical Engineering and Presidential Impact Fellow. “This newly designed hydrogel ink is highly biocompatible and electrically conductive, paving the way for the next generation of wearable and implantable bioelectronics.”
This study has just been published in ACS Nano.
The ink has shear-thinning properties that decrease in viscosity as the force increases, so it is solid inside the tube but flows more like a liquid when squeezed, similar to ketchup or toothpaste. The team incorporated these electrically conductive nanomaterials into a modified gelatin to make a hydrogel ink with essential characteristics to design an ink suitable for 3D printing.
“These 3D-printed devices are extremely elastomeric and can be compressed, bent, or twisted without breaking,” said Kaivalya Deo, graduate student in the Department of Biomedical Engineering and lead author of the paper. “Additionally, these devices are electronically active, allowing them to monitor dynamic human movements and paving the way for continuous movement monitoring.”
In order to 3D print the ink, researchers at the Gaharwar lab designed a cost-effective, fully functional and customizable open source multi-head 3D bio-printer, running on open source tools and free software. It also allows any researcher to build 3D bio-printers tailored to their own research needs.
3D printed electrically conductive hydrogel ink can create complex 3D circuits and is not limited to flat designs, allowing researchers to create customizable bioelectronics tailored to specific patient needs.
Using these 3D printers, Deo was able to print electrically active and expandable electronic devices. These devices exhibit extraordinary strain sensing capabilities and can be used to design customizable monitoring systems. It also opens up new possibilities for designing stretchable sensors with integrated microelectronic components.
One of the potential applications for the new ink is the 3D printing of electronic tattoos for patients with Parkinson’s disease. Researchers envision that this printed electronic tattoo can monitor a patient’s movements, including tremors.
This project is in collaboration with Dr. Anthony Guiseppi-Elie, Vice President of Academic Affairs and Workforce Development at Tri-County Technical College, and Dr. Limei Tian, Assistant Professor of Biomedical Engineering at Texas A&M.
This study was funded by the National Institute of Biomedical Imaging and Bioengineering, the National Institute of Neurological Disorders and Stroke, and the Texas A&M University President’s Excellence Fund. A provisional patent on this technology has been filed in association with the Texas A&M Engineering Experiment Station.
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Material provided by Texas A&M University. Original written by Alleynah Veatch Cofas. Note: Content may be edited for style and length.