Development of an Acoustic Implant Protection System to Improve Performance and Longevity of Neural Interfaces

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This SBIR Fast-track finalizes, tests, and commercializes the Acoustic Implant Protection (AIP) system, which uses the application of precision acoustic fields to penetrating neural implants to prevent electrode impedance rise and improve implant longevity. This submission is in response to: Notice of Special Interest (NOSI): NOT- MH-21-125 Translation of BRAIN Initiative Technologies to the Marketplace. Problem to be solved: Chronic neural implants hold great potential for illuminating features of neural function, treating neurological disorders, and enabling the next generation of brain-machine interface-based neuroprosthetics. Penetrating microelectrode arrays provide direct access to neural signals with high temporospatial resolution. However, their preclinical and clinical viability are limited by their poor longevity and variability in functionality due to the immune response or foreign body response (FBR). The FBR can cause glial scarring and neural cell loss near the electrode sites of penetrating arrays over a period of several weeks, which are leading causes of signal recording losses through both electrical isolation and spatial distancing effects. The FBR begins with electrode insertion, when damage to the blood brain barrier activates astrocytes and microglia. Although ‘soft’ electrode materials, thinner shanks, and floating arrays have been developed to minimize the mismatch between brain and implant, none of these have demonstrated sufficient recording life and immunity to the FBR. Exogenous chemical means have been used to directly suppress the FBR, and have yielded positive results to varying degrees, but limitations of effectiveness, high costs, and/or undesirable side-effects still exist. A simple approach is needed to mitigate FBR for both preclinical and clinical use. Solution: Sub-threshold therapeutic ultrasound has recently been shown to have protective and healing effects in models of cerebral disease and injury, through promotion of neurotrophic factors. AMI successfully leveraged this principle in an R21 study evaluating low-intensity pulsed ultrasound (LIPUS) to mitigate the microglia response and improve longevity of neural interfaces. Product: This Fast-track delivers an AIP system for preclinical use with a reusable (releasable) annular transducer that delivers LIPUS to produce a neuro-protective environment around implanted microelectrodes. Phase I: Aim 1 – Electronics/System Adaptation for Preclinical Study. Aim 2 – Confirm ultrasound parameters for AIP annulus that safely stimulate cortical tissues comparable to Alpha design from R21. Phase I to Phase II Go-no-go. Portable, reusable AIP prototype produces measurable improvement in neural signal longevity over 6 weeks in preclinical microelectrode study. Positive feedback from potential end users. Aim 3– Integrate End User Design Feedback and Conduct Verification and Validation. Aim 4 – Optimize stimulation intervals for neural interface performance (SNR, unit detection) and demonstrate additional neuro- protective effects (glial cell activation, E-I balance) of LIPUS in preclinical studies.