Development of a piezoelectric inchworm machine for automatic microelectrode implantation into brain with meningeal layer penetration

University Of Massachusetts Lowell, Lowell MA

Investigators

Abstract

Large-scale chronic recording from across the brain with minimal disruption is an ideal neuroscientific experiment and a BRAIN Initiative goal since it will help us understand brain mechanisms. While small-size minimally-damaging flexible electrodes are the ideal choice for such recordings, they are also the most difficult to use with current surgical methods, due to electrode buckling and labor-intensive handling of these tiny devices during surgery. A full-functioning system to implant multiple types of electrodes across multi-brain regions in an automated buckling-free fashion while integrating with typically used neuroscience lab surgical equipment is critical for expanding brain signal acquisition capabilities. An instrument that circumvents electrode buckling and non-automated insertion will enable researchers to reach deeper brain structures with previously-too-small minimally damaging electrode arrays and conduct currently unfeasible large-scale recordings and stimulations. More importantly, methodologies developed for such a system would be widely applicable since the principles and mechanics can extend to different animal brains, or more broadly to most tissue membrane penetration cases like biopsy and drug delivery. The goal of this project is to develop a piezoelectric inchworm insertion mechanism and integrate it with a 3D-printed skull cap platform to enable currently impractical high-density broad-scale implantation of miniaturized flexible microelectrodes in a fast and extensible machine-controlled manner. Specifically, in this project, to tackle the buckling problem, the inchworm-skull cap system will provide full support above the membranes and insert only the electrodes (no invasive support/shuttle) with less than 100 μm increments through iterative grip-feed-release inchworm motion. To address the automation challenge, the machine-controlled alignment and insertion with micrometer-level precision, speed control, and potential vibration assistance will reduce surgical time, complication risk, and surgeon fatigue – leading to improved outcomes. The project contains three synergistic tasks: (1) develop and prototype a piezoelectric inchworm machine for planar probes (both silicon-based and flexible), (2) build an inchworm with specialized grippers for multi-microwire arrays, and (3) automate the labor-intensive alignment process of arrays/probes to their insertion start location, driven by image processing and feature recognition. Surgical and electrophysiological recording improvements will be quantified and evaluated through animal studies to guide iterative optimization. The results of the project can be found at: http://leichen.info/. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.