Optical neural stimulation using the thermoplasmonic effect of gold nano-hexagon

HASSAN TAJARENEJAD, MOHAMMAD ALI ANSARI, * SOHEILA AKBARI, HANIEH YAZDANFAR, AND SEYEDEH MEHRI HAMIDI

The use of nanoparticle’s photothermal effect as adjuvants in neuromodulation has recently received much attention with many open questions consists of new kind of nanostructures’s effect onto action potential. This paper will study the photothermal properties of hexagonal gold nanoparticles, including absorption peak wavelength and light-heat conversion rate in both experimental and simulation. Furthermore, the ability to use these nanostructures in axonal neural stimulation and cardiac stimulation by measuring temperature changes of gold nano-hexagon under 532 nm laser irradiation is studied. In addition, their thermal effect on neural responses is investigated by modeling small-diameter unmyelinated axons and heart pacemakers’ cells. The results show that the increase in temperature caused by these nano-hexagons can successfully stimulate the small diameter axon and produce an action potential. Moreover, it is shown experimentally that produced heat by AuNSs affected toad heart rhythm and increased T wave amplitude. An increase in T wave amplitude on toad heart rhythm shows the thermal effect of nano hexagons heat on heart pacemakers cells and intracellular ion flows. This article shows the potential of using these nanostructures to build portable and compact devices for medical uses as a new method for optical pacemakers or cardiac stimulation.