Modulation of neuronal activity using photothermal stimulation of gold nanorod

Abstract

The ability to switch the neuronal activity in a spatio-temporally controllable means provides the opportunity to understand the intricately linked information in the brain. Recently, optical tool is able to control from neural network operating to organism behavior by stimulating the genetically programmed nerve cells. However, optical approaches have limits in low penetrability of the visible light, necessity of gene transfection and photothermal damages. Here, this study demonstrates that neuronal firing could be effectively modulated through the advanced phoththermal stimulation. In order to minimize the light absorption by the cell, near infrared was used as a photothermal energy source. And gold nanorod was optimized for absorbing the near infrared, which converted to thermal energy on the nanorod surfaces. Toxicity of gold nanorod was settled by surface coating with polyelectrolytes. Using the photothermal stimuli, this study found that neural firing rate could be modulated by suppressing the neuron activity and it could be suppressed up to 100% with high reproducibility and long-term stability. This study represents high performance and possibility to be a new class of stimulation method. Thus, it could be applied to many neuroscientific researches and disorder therapeutics.