Distributed free-floating wireless implantable neural recording system

Abstract

The objective of the research is to design, implement, test, and characterize a new wireless neural interfacing tool that can simultaneously record large scale neuronal ensembles over the entire brain area for a long term (>1 yr). This thesis work includes a novel design concept for a standalone free-floating wireless implantable neural recording (FF-WINeR) system with a total volume of less than 1 mm3 as well as the development of each fundamental system component. For system operation and control, two FF-WINeR application specific integrated circuits (ASIC) with constrained silicon area and power budget were designed and tested. The specifications and features of the ASIC have been determined based on comprehensive studies on wireless power and data delivery utilizing 3-/4-coil inductive links for distributed millimeter-sized implantable medical devices (IMDs) with less than 1 mm3 volume. Moreover, approaches for an optimal geometrical design of the inductive link have been studies. To develop a user-friendly “push-pin” shaped neural probe applicable in a clinical environment, two novel process flows for micromachining the neural probes and microassembly of the FF-WINeR will be discussed. To estimate the life-span of the hermetically sealed FF-WINeR probes, an automated high-throughput hermetic failure monitoring system has been developed. Furthermore, a possible surgical procedure and a future in-vivo experimental setup for the FF-WINeR probes are proposed based on histology results from a short-term animal surgery.