# Nongenetic Photostimulation of hiPSC Neurons Using Plasmonic Nanopyramids

## TL;DR

Researchers developed a new method to stimulate neurons using light without genetic modification, improving electrophysiological studies of human stem cell-derived neurons.

## Contribution

A plasmonic nanopyramid-based system enables nongenetic photostimulation of hiPSC neurons with low light intensity and minimal physiological disruption.

## Key findings

- Plasmonic gold pyramids on TiN MEAs increased photocurrent by over 30-fold and reduced electrode impedance by 6-fold.
- The system allows efficient neuronal photostimulation at low light intensities with minimal perturbation.
- The approach combines optical stimulation with high-resolution electrophysiological recording for precise control of neuronal activity.

## Abstract

Human-induced pluripotent
stem cell (hiPSC)–derived neurons
offer a powerful platform for replicating key aspects of human neurodevelopment,
synaptic connectivity, and ion channel expression. However, their
electrophysiological investigation remains challenging, particularly
for studies aiming to elicit neuronal activity with minimal perturbation
of physiological conditions. In this study, we integrated plasmonic
gold pyramids onto commercial titanium nitride (TiN) microelectrode
arrays (MEAs). The presence of these plasmonic structures enhanced
the generated photocurrent by more than 30-fold and simultaneously
reduced the electrode impedance by approximately 6-fold. Leveraging
the unique optical properties of plasmonic nanostructures, we demonstrate
that gold pyramids enable efficient neuronal photostimulation at low
light intensities with minimal perturbations. Our approach combines
nongenetic optical stimulation with high-resolution electrophysiological
recording, providing precise spatiotemporal control of neuronal activity.
These advances highlight the potential of our plasmonically enhanced
MEA technology to bridge the gap between preclinical research and
human neurological applications.