My friend can't wait to become bionic. To be replaced and immortalised by electronics and synthetic materials built to last. Materials specifically shaped to cover him atom by atom and help his body repair itself.
So I told him about the invention of 3D-printed graphene, an innovation that "combines a miracle material with a revolutionary manufacturing technology", according to its creators at Northwestern University in Chicago.
Graphene is a form of carbon laid out in honeycomb sheets just one atom thick. Discovered in 2004, it has remarkable properties: it is 207 times stronger than steel by weight; it conducts heat and electricity efficiently, and it is nearly transparent. As plenty of tissues in the body rely heavily on electric processes, such as muscles, nerves, heart tissue, and even bone, graphene could, in theory, be used to help repair and regenerate damaged tissues.
However, successful biomedical applications of graphene have proved challenging. Graphene is difficult to work with in bulk, and attempts to build truly 3D structures from it have relied heavily on mixing it with high proportions of polymers. "They are essentially plastics with a little boost," says Professor Ramille Shah of Northwestern University in Chicago.
Instead, Shah's Tissue Engineering and Additive Manufacturing lab came up with a better solution that takes advantage of all that graphene has to offer. They created an ink that is 3D-printable at room temperature and contains at least 60 per cent graphene. The ink, called 3DG, is a liquid that hardens as soon as it’s squeezed out, allowing thousands of layers of graphene to solidify quickly and create precise and widely varying structures.
"This result itself is exciting, but it was the combined mechanical, electrical and biological properties of the printed 3DG material that make it particularly fascinating and gives it promise for being clinically useful, rather than being restricted to purely academic value," says Shah.
The resulting structures are flexible, electrically–conductive and easy to manipulate during surgery, allowing surgeons to shape them by rolling, folding, cutting and then stitching them together. Shah’s team tested 3DG structures in human corpses, showing how easily they could be manipulated. Graphene ink structures have also been tested in mice and found to be biocompatible – meaning the immune system did not attack them – which is key.
Finally, Shah’s team showed that the structures can be broken down and safely disposed of by natural processes in the body. This is important as it means graphene implants can safely disappear once their job is done. For example, 3DG could be used to create flexible, biodegradable and implantable biosensors, such as those that locally monitor heart or nerve electrical activity, and gradually degrade after they have served their purpose.
We may be someway off becoming bionic beings entirely, but with advances like this, my friend’s dream might just be that much closer.