# A Neuroelectronic Interface with Microstructured Substrates for Spiral Ganglion Neurons Cultured In Vitro: Proof of Concept

## TL;DR

Researchers developed a neuroelectronic interface to study spiral ganglion neurons in a 3D environment, showing how neurons respond to microstructured surfaces and electrical stimulation.

## Contribution

A novel neuroelectronic interface with microstructured substrates that supports in vitro SGN growth and enables extracellular recording and stimulation.

## Key findings

- SGNs cultured on micro-patterned substrates showed viable growth and neurophysiological activity.
- Local field potentials resembling action potentials were elicited through electrical stimulation.
- The interface supports mechanotaxis-driven guidance and neuron-electrode interactions.

## Abstract

In this study, we present a proof-of-concept neuroelectronic interface (NEI) for extracellular stimulation and recording of neurophysiological activity in spiral ganglion neurons (SGNs) cultured in vitro on three-dimensional, micro-patterned substrates with customized microtopographies, integrated within a 196-channel microelectrode array (MEA). This approach enables mechanotaxis-driven neuronal contact guidance, promoting SGN growth and development, which is highly sensitive to artificial in vitro environments. The microtopography geometry was optimized based on our previous studies to enhance SGN alignment and neuron-electrode interactions. The NEI was validated using SGNs dissociated from rat pups in the prehearing period and cultured for seven days in vitro (DIV). We observed viable and proliferative cellular cultures with robust neurophysiological responses in the form of local field potentials (LFPs) resembling action potentials (APs), elicited both spontaneously and through electrical stimulation. These findings provide deeper insights into SGN behavior and neuron-microenvironment interactions, laying the groundwork for further advancements in neuroelectronic systems.