gizmodo.com/scientists-just...
From 2015
“A group of chemists and engineers who work with nanotechnology published a paper this month in Nature Nanotechnology about an ultra-fine mesh that can merge into the brain to create what appears to be a seamless interface between machine and biological circuitry. Called “mesh electronics,” the device is so thin and supple that it can be injected with a needle — they’ve already tested it on mice, who survived the implantation and are thriving. The researchers describe their device as “syringe-injectable electronics,” and say it has a number of uses, including monitoring brain activity, delivering treatment for degenerative disorders like Parkinson’s, and even enhancing brain capabilities.“
Elon musk says the books were the inspiration for his work on brains.