Steerable Microinvasive Probes for Localized Drug Delivery to Deep Tissue

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Neuropathology research necessitates advanced tools for precise neural targeting and drug delivery.
• Current neural implants cause significant glial scarring and lack precise localization.
• Smaller implants reduce trauma but require sophisticated control for accurate subcortical placement.

Purpose of the Study:

• To develop novel steerable microinvasive neural implants (S-MINIs) for precise, chronic implantation in subcortical structures.
• To overcome limitations of current neural implants, including glial scarring and imprecise drug delivery.
• To enable accurate targeting without complex closed-loop control systems.

Main Methods:

• Construction of S-MINIs from borosilicate capillaries (60 µm OD, 20 µm ID).
• Utilizing bevel-steered needles for open-loop targeting of deep-brain structures.
• In vitro and ex vivo characterization of the relationship between bevel angle and trajectory radius of curvature.

Main Results:

• S-MINIs demonstrated a 3.5-fold reduction in glial scarring compared to previous implants.
• A sinusoidal relationship between bevel angle and trajectory radius of curvature was established.
• Open-loop steering achieved accurate targeting of deep-brain structures with an average error of 0.23 mm ± 0.19 mm.

Conclusions:

• Steerable microinvasive neural implants (S-MINIs) offer a new microinvasive tool for chronic and predictable targeting.
• Polished microcapillaries enable precise navigation to pathophysiological targets without closed-loop feedback.
• This technology advances neural implant design, reducing surgical trauma and improving spatial resolution for neuropathology treatment.