The live fish’s electrical systems are inside them

Growth of electronic devices in the brains of living animals by polymerizing a gel into a flexible material containing Enzymes, glucose and lactate

Electronic devices or circuitry that can be implanted in the body have many potential applications in medicine and research, such as helping the brain to communicate with prosthetic limbs, or even enhancing memory. Conventional electronic materials can cause inflammation or scarring if they get inside living tissue, and they often end up shutting down.

The gel is transformed into a flexible material by a chain reaction of the recipient’s own chemicals.

“We are performing a lot of experiments with these materials to grow electrodes and electronics around cells,” says study co-author Magnus Berggren, a materials scientist at the Linköping University in Sweden. He adds that the work could ultimately improve technologies for deep-brain stimulation, for example, or help damaged nerves to regrow.

The material doesn’t oxidize until it is in the body, and it is soft, so it doesn’t have the same mechanical differences as living tissue.

They created a mixture which contained the chemical building blocks along with Enzymes. When injected into living tissue, the gel reacts with the common metabolites glucose and lactate, which causes the gel to polymerize into a much firmer — although still soft — material. The scientists used this approach to produce a substance inside the brains and fins of a living animal. They also used it in the nervous tissue of leeches and in muscle tissue from chickens, pigs and cows.

There are still many obstacles that need to be overcome before people can be tested for the substance. Even though the polymer is highly conductive, for example, there is currently no way to make it functional by connecting it to an outside electricity source.

The researchers also need to do more tests to establish that the approach is safe. They did not observe any unusual behavior in the animals after they injected the solution into their brains and they monitored them for three days. “They need to look at long-term chronic responses,” says Inal.

Our world is populated by hundreds of thousands of cyborgs. Parkinson’s patients can shut their tremors down with metal electrodes implanted deep inside their brains. Others—albeit far fewer—are completely paralyzed people who can move robotic limbs with their minds, thanks to their own implants. Such technologies can radically improve someone’s quality of life. But they have a major problem: Metal and the brain get along very, very poorly.

Brains are squishy and will come apart into clumps if pushed too hard. There’s a violence to probing the brain with wires. “It’s like sticking a knife into the tissue,” says Magnus Berggren, professor of organic electronics at Linköping University in Sweden.

The brain jiggles and shifts around when electrodes are relatively fixed, causing more injury. The body responds by forming scar tissue, which gradually walls off the electrode from the neurons that it is supposed to record or stimulate. Utah array, a tiny hair brush-like device that helps paralyzed patients move their limbs, is usually removed after five years due to the scarring on the brain.