Highly Branched Au Superparticles as Efficient Photothermal Transducers for Optical Neuromodulation.

Precise neuromodulation is critical for interrogating cellular communication and treating neurological diseases. Nanoscale transducers have emerged as effective interfaces to exert photothermal effects and modulate neural activities with a high spatiotemporal resolution. Ideal materials for this application should possess strong light absorption, high photothermal conversion efficiency, and great biocompatibility for clinical translation. Here, we show that the structurally designed 3D Au superparticles with a highly branched morphology can be promising candidates for nongenetic and remote neuromodulation. The structure-induced blackbody-like absorption endows Au superparticles with photothermal conversion efficiency over 90%, much higher than that of conventional Au nanorods. With the biocompatible polydopamine ligands, Au superparticles can be readily interfaced with primary mouse hippocampal neurons and other cells and can photostimulate or inhibit their activities in both cell networks or with a single-cell resolution. These findings highlight the importance of structural designs as powerful tools to promote the performance of plasmonic materials in neuromodulation and related research of neuroscience and neuroengineering.