A team of researchers at Texas A&M University has developed a new class of biomaterial inks that mimic native characteristics of highly conductive human tissue, much like skin, and can be used in 3D printing. The new inks could potentially be used to create flexible electronics that can be integrated with the human body.
‘The impact of this work is far-reaching in 3D printing,’ said Akhilesh Gaharwar, an associate professor in the Department of Biomedical Engineering. ‘This newly designed hydrogel ink is highly biocompatible and electrically conductive, paving the way for the next generation of wearable and implantable bioelectronics.’
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The biomaterial ink incorporates a new class of 2D nanomaterials known as molybdenum disulfide, whose thin-layered structure contains defect centres that make it chemically active. The team incorporated these electrically conductive nanomaterials within a modified gelatin to make a hydrogel ink with characteristics that are essential for designing ink conducive to 3D printing. The ink has shear-thinning properties that decrease in viscosity as force increases, so it’s solid inside the tube but flows more like a liquid when squeezed, similar to ketchup or toothpaste.
‘These 3D-printed devices are extremely elastomeric and can be compressed, bent or twisted without breaking,’ said Kaivalya Deo (pictured above), a graduate student in the biomedical engineering department. ‘In addition, these devices are electronically active, enabling them to monitor dynamic human motion and paving the way for continuous motion monitoring.’
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In order to 3D print the ink, researchers in the Gaharwar Laboratory designed a cost-effective, open-source, multi-head 3D bioprinter that’s fully functional and customisable, running on open-source tools and freeware.
The electrically conductive 3D-printed hydrogel ink can create complex 3D circuits and isn’t limited to planar designs, allowing researchers to make customisable bioelectronics tailored to patient-specific requirements.
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Using the new ink, Deo was able to print electrically active and stretchable electronic devices. These devices demonstrate extraordinary strain-sensing capabilities and can be used for engineering customisable monitoring systems. This also opens up new possibilities for designing stretchable sensors with integrated microelectronic components.
One of the potential applications of the new ink is in 3D printing electronic tattoos for patients with Parkinson’s disease. Researchers envision that this printed e-tattoo can monitor a patient’s movement, including tremors.
The research has been published in ACS Nano.