Minimally invasive electrodes of cellular scale that approach a bio-integrative level of neural recording could enable the development of scalable brain machine interfaces that stably interface with the same neural populations over long period of time. In this paper, we designed and created NeuroRoots, a bio-mimetic multi-channel implant sharing similar dimension (10μm wide, 1.5μm thick), mechanical flexibility and spatial distribution as axon bundles in the brain. A simple approach of delivery is reported based on the assembly and controllable immobilization of the electrode onto a 35μm microwire shuttle by using capillarity and surface-tension in aqueous solution. Once implanted into targeted regions of the brain, the microwire was retracted leaving NeuroRoots in the biological tissue with minimal surgical footprint and perturbation of existing neural architectures within the tissue. NeuroRoots was implanted using a platform compatible with commercially available electrophysiology rigs and with measurements of interests in behavioral experiments in adult rats freely moving into maze. We demonstrated that NeuroRoots electrodes reliably detected action potentials for at least 7 weeks and the signal amplitude and shape remained relatively constant during long-term implantation. This research represents a step forward in the direction of developing the next generation of seamless brain-machine interface to study and modulate the activities of specific sub- populations of neurons, and to develop therapies for a plethora of neurological diseases.

NeuroRoots, a bio-inspired, seamless Brain Machine Interface device for long-term recording.