Extracellular electrical stimulation by ferroelectric displacement current in the switching regime

TL;DR

This paper demonstrates that ferroelectric polarization current in coated microelectrodes significantly enhances extracellular stimulation efficiency, potentially increasing charge injection capacity by up to two orders of magnitude compared to traditional dielectric coatings.

Contribution

It introduces the use of ferroelectric layers in microelectrodes to leverage polarization current for improved extracellular stimulation in bioelectronic devices.

Findings

Ferroelectric polarization current contributes to extracellular stimulation current.

Switching regime polarization can increase charge injection capacity by up to 100 times.

Ferroelectric coatings outperform dielectric layers in stimulation efficiency.

Abstract

We analyze the extracellular stimulation current and the charge injection capacitity (CIC) of microelectrodes coated with an insulating layer to prevent toxic electrochemical effects in bioelectronic applications. We show for a microelectrode coated with an insulating ferroelectric layer, that the ferroelectric polarization current contributes to the extracellular stimulation current. Depending on the remanent polarization $P_{\rm r}$ of the ferroelectric, the polarization current in the switching regime can increase the CIC by up to two orders of magnitude as compared to the commonly used extracellular capacitive stimulation with microelectrodes that are coated with a dielectric layer.