Flexible intracerebral probes for neural recording and electrical stimulation have been the focus of many research works to achieve better compliance with the surrounding tissue while minimizing rejection. Strategies have been explored to find the best way to insert flexible probes into the brain while maintaining their flexibility once positioned. Here, we present a novel and versatile scalable batch fabrication approach to deliver ultrathin and flexible probes consisting of a silk-parylene bilayer. The biodegradable silk layer, whose degradation time is programmable, provides a temporary and programmable stiffener to allow the insertion of ultrathin parylene-based flexible devices. Our innovative and robust batch fabrication technology allows complete freedom over probe design in terms of materials, size, shape, and thickness. We demonstrate successful ex vivo insertion of the probe with acute high-fidelity recordings of epileptic seizures in field potentials as well as single-unit action potentials in mouse brain slices. Our novel technological solution for implanting ultraflexible devices in the brain while minimizing rejection risks shows high potential for use in both brain research and clinical therapies.

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Flexible deep brain probes have been the focus of many research works and aims at achieving better compliance with the surrounding brain tissue while maintaining minimal rejection. Strategies have been explored to find the best way to implant a flexible probe in the brain, while maintaining its flexibility once positioned in the cortex. Here, we present a novel and versatile scalable batch fabrication approach to deliver ultra-thin and flexible penetrating neural probe consisting of a silk-parylene bilayer. The biodegradable silk layer provides a temporary and programmable stiffener to ensure ease of insertion of the ultrathin parylene-based flexible devices. The innovative and yet robust batch fabrication technology allows complete design freedom of the neural probe in terms of materials, size, shape and thickness. These results provide a novel technological solution for implanting ultra-flexible and ultrathin devices, which possesses great potential for brain research.