Steerable Microinvasive Probes for Localized Drug Delivery to Deep Tissue

Max J. Cotler, Erin B. Rousseau, Khalil B. Ramadi, Joshua Fang, Ann M. Graybiel, Robert Langer, Michael J. Cima

    Research output: Contribution to journalArticle

    Abstract

    Enhanced understanding of neuropathologies has created a need for more advanced tools. Current neural implants result in extensive glial scarring and are not able to highly localize drug delivery due to their size. Smaller implants reduce surgical trauma and improve spatial resolution, but such a reduction requires improvements in device design to enable accurate and chronic implantation in subcortical structures. Flexible needle steering techniques offer improved control over implant placement, but often require complex closed-loop control for accurate implantation. This study reports the development of steerable microinvasive neural implants (S-MINIs) constructed from borosilicate capillaries (OD = 60 µm, ID = 20 µm) that do not require closed-loop guidance or guide tubes. S-MINIs reduce glial scarring 3.5-fold compared to prior implants. Bevel steered needles are utilized for open-loop targeting of deep-brain structures. This study demonstrates a sinusoidal relationship between implant bevel angle and the trajectory radius of curvature both in vitro and ex vivo. This relationship allows for bevel-tipped capillaries to be steered to a target with an average error of 0.23 mm ± 0.19 without closed-loop control. Polished microcapillaries present a new microinvasive tool for chronic, predictable targeting of pathophysiological structures without the need for closed-loop feedback and complex imaging.

    Original languageEnglish (US)
    Article number1901459
    JournalSmall
    Volume15
    Issue number37
    DOIs
    StatePublished - Sep 1 2019

    Keywords

    • borosilicate
    • drug delivery
    • needle steering
    • neuroengineering

    ASJC Scopus subject areas

    • Biotechnology
    • Biomaterials
    • Chemistry(all)
    • Materials Science(all)

    Fingerprint Dive into the research topics of 'Steerable Microinvasive Probes for Localized Drug Delivery to Deep Tissue'. Together they form a unique fingerprint.

  • Cite this

    Cotler, M. J., Rousseau, E. B., Ramadi, K. B., Fang, J., Graybiel, A. M., Langer, R., & Cima, M. J. (2019). Steerable Microinvasive Probes for Localized Drug Delivery to Deep Tissue. Small, 15(37), [1901459]. https://doi.org/10.1002/smll.201901459