Brain-computer interfaces (BCIs) are a hot topic these days, with companies like Neuralink racing to create devices that connect humans’ brains to machines via tiny implanted electrodes. The potential benefits of BCIs range from improved monitoring of brain activity in patients with neurological problems to restoring vision in blind people to allowing humans to control machines using only our minds. But a major hurdle for the development of these devices is the electrodes themselves – they must conduct electricity, so nearly all of them are made of metal. Metals are not the most brain-friendly materials, as they are hard, rigid, and don’t replicate the physical environment in which brain cells typically grow.
