Bouquet Fiber-based Neural Probe

THE PROBLEM

Neural probes are the key to unlocking the brain’s mysteries, yet current designs remain woefully inadequate. Most cutting-edge probes rely on outdated tip-based interactions, offering only a narrow, fragmented view of neural activity while leaving vast brain regions unexplored. Bulky, rigid structures provoke inflammation and tissue damage, jeopardizing long-term viability. The integration of electrical, optical, and fluidic functions into a single, flexible platform remains an elusive challenge, leading to unreliable performance and soaring costs. Worse still, signal drift, material degradation, and biofouling undermine stability over time. To truly revolutionize neuroscience and clinical applications, we must develop a new generation of neural probes—ones that seamlessly conform to the brain’s complexity while enabling expansive, multifunctional interfacing like never before.

OUR SOLUTION

Spatially expandable fiber probes invented at Virginia Tech revolutionize neural interfacing by enabling multi-site recording, stimulation, and drug delivery across extensive brain regions while minimizing invasiveness. Unlike conventional tip-based designs, these probes feature helical scaffolds that house flexible fibers capable of extending in multiple directions. Femtosecond laser micromachining creates precise electrode, optical, and fluidic “windows” along their length, allowing targeted three-dimensional interactions. Manufactured using thermally drawn polymer techniques, these probes maintain low impedance, effective optical transmission, and long-term stability. This innovative approach provides an adaptable, multifunctional platform that overcomes the limitations of traditional neural probes, unlocking new possibilities for neuroscience research and clinical applications.

The novel scaffolding fiber is inserted into the brain and affixed by Metabond. When the functional fibers are inserted into the brain tissue through the scaffolding fiber, they can spread out into the deeper tissues.

Novel Concepts

1. Helical scaffold with multiple slidable probe channels: Existing neural probe systems typically rely on fixed shanks or bundles without a helically structured scaffold that allows for post-insertion, directional extension into distant brain regions.
2. “Bouquet” or tree-like probe arrangement: While multi-shank probes and stent-electrode arrays exist, a nested, tree-like structure with individually rotatable channels for creating complex three-dimensional “webs” of electrodes or waveguides is new.
3. Scalable branched architecture integrating high-density electrodes, waveguides, and fluidic channels: The invention’s ability to incorporate a large number of components (e.g., 16 branches, each with multiple electrodes, waveguides, and channels) in a branched, expanding scaffold is novel. The scale and geometry of this branching design will enable more extensive coverage of larger brain regions than existing probes.

Advantages

1. 3D Multisite Interfacing: Provides interfacing along the entire fiber length rather than just at the tip, surpassing traditional probes that are limited to fixed, tip-based recording sites.
2. Minimized Tissue Damage with Enhanced Flexibility: Utilizes flexible, spatially expandable scaffolds that lower bending stiffness compared to conventional stainless steel wires, reducing tissue damage and chronic inflammatory responses.
3. Integrated Multi-Modal Functionality: Combines electrical recording, optical stimulation, and chemical delivery in a single probe, overcoming the need for separate devices as seen in traditional systems where optical fibers or drug delivery catheters are added to standard electrode arrays.
4. Precision via Femtosecond Laser Micromachining: Employs femtosecond laser micromachining to create microscale interfacing windows (~10µm) along the fiber, offering superior spatial precision compared to conventional photolithographic or mechanical milling techniques.
5. Scalable and Customizable Spatial Expansion: The helical scaffold design enables controlled expansion to target dispersed brain regions, a distinct advantage over fixed, planar electrode arrays that lack three-dimensional adaptability.
6. Long-Term Stability and Biocompatibility: Demonstrated capability for chronic neural interfacing with stable electrical performance and minimal immune response, addressing challenges seen in older silicon-based and metal electrode probes.