Biomedical engineers developed an electrode that can be injected as a liquid and then cure in the body, creating the groundwork for a new kind of neural interface system.
Today's neuromodulation treatments rely on expensive surgically implanted devices that require complex procedures to install and often fail since they are rigid devices attempting to mesh with soft biological tissue.
The new liquid can be injected around the nerve where it cures in the body to create a wired contact. Typical implants are stiff, so as the body moves, they wear and tear and break down. The liquid cures, so the result is much closer to the normal elasticity of tissue. It can actually be stretched and its size increased 150 to 200 percent without losing its conductivity.
To create the injectrode, the researchers mixed a silicone base — similar to surgical glue — with small metal particles to make the liquid sufficiently conductive.
The team is testing a scheme in which they inject the fluid around the nerve, then extrude a thin insulated string of the material back to just underneath the surface of the skin, where they inject more of the composite material. Then they can use a basic transcutaneous electrical nerve stimulation (TENS) unit to stimulate the nerve from the surface of the skin, making the whole setup less expensive and more adaptable compared to traditional implanted electrodes.
The researchers made a bypass from the surface of the skin to the location to be stimulated. Eventually, a robotic surgical system could be used for a procedure that would be akin to getting a tattoo.