A new kind of graphene ink can print 3D structures that could one day be used for biomedical engineering and electronic devices. A team of researchers at Northwestern University developed the ink by mixing graphene flakes with a biocompatible elastomer and quickly evaporating solvents. This method, the researchers say, allows them to add higher volumes of graphene than other attempts, which have diluted graphene in order to ensure that the end result isn’t too brittle or fragile. Researcher Ramille Shah said, “People have tried to print graphene before, but it’s been a mostly polymer composite with graphene making up less than 20 percent of the volume.” Her team’s ink is made of up to 70 percent graphene, but it’s still flexible and strong enough to print macroscopic structures.
Although graphene is a novel material with enormous potential, it isn’t widely used yet because it is so difficult to manipulate. However, 11 years after its discovery, researchers are making progress. A team at the University of Manchester, for example, recently printed graphene RFID antennas on paper. The Northwestern team is focused on biomedical applications. They developed the ink to 3D print scaffolds that can be used in tissue engineering and regenerative medicine.
“Cells conduct electricity inherently — especially neurons,” Shah said. “So if they’re on a substrate that can help conduct that signal, they’re able to communicate over wider distances.” Shah’s team has already seen promising results by experimenting with populating the scaffolds with stem cells to create neuron-like cells. The graphene structure can also be sutured to existing tissues, so it is a potential material for biodegradable sensors and medical implants. The 3D printed graphene structures are featured on the cover of the April 2015 issue of ACS Nano, which includes a paper describing the work in detail.