Self-Stretchable Christmas-Tree-Shaped Ultraflexible Neural Probes

We devised a novel Christmas-tree structure for flexible neural probes, which features recording sites on side-branches that can be folded along the shank of the probe by temporary encapsulation before implantation. This design reduces the size of the implant and minimizes the surgical footprint. Upon implantation, the temporary encapsulation dissolves in vivo, leading to self-stretching of the branches, and an expansion of the lateral detecting range of the probe. We conducted in vitro experiment with our probe in 0.6% agar that mimics the brain tissue environment. The results demonstrate that the neural probe we have developed exhibits self-stretching ability and provides an increased lateral recording range without causing additional damage to the brain tissue.