Development of a chipscale integrated microelectrode/microelectronic device for brain implantable neuroengineering applications

TLDR

The authors propose a photovoltaic power converter and encapsulation strategy to support chronic implantation of the neuroport. They integrated an ultralow‑power analog CMOS chip with a silicon microelectrode array into a microminiaturized neuroport, incorporating preamplifier and multiplexing circuitry and a hybrid flip‑chip bonding technique for encapsulation. The neuroport demonstrated suitable recording characteristics via pseudospike detection and local excitation measurement, and successfully recorded local field potentials from rat thalamocortical slices, indicating its potential as a single‑implant microminiaturized neural interface.

Abstract

An ultralow power analog CMOS chip and a silicon based microelectrode array have been fully integrated to a microminiaturized "neuroport" for brain implantable neuroengineering applications. The CMOS integrated circuit (IC) includes preamplifier and multiplexing circuitry, and a hybrid flip-chip bonding technique was developed to fabricate a functional, encapsulated microminiaturized neuroprobe device. Our neuroport has been evaluated using various methods, including pseudospike detection and local excitation measurement, and showed suitable characteristics for recording neural activities. As a proof-of-concept demonstration, we have measured local field potentials from thalamocortical brain slices of rats, suggesting that the new neuroport can form a prime platform for the development of a microminiaturized neural interface to the brain in a single implantable unit. An alternative power delivery scheme using photovoltaic power converter, and an encapsulation strategy for chronic implantation are also discussed.