Electro-Plasmonic Brain-Machine Interfaces

A novel high-throughput, high-resolution platform for electrophysiology is presented as the foundation of a new generation of brain-machine interfaces. Scientists and engineers have pursued large scale neural sensing for decades; however, physical limitations associated with electrical (electrode-based) field recordings hinder advances in both field of view and spatial resolution. Electrochromic plasmonics (electro-plasmonics) has recently emerged as a novel extracellular method for label-free optical electrophysiological sensing. However, initial demonstrations were limited to dark field measurements, which are not suitable for large area imaging applications. In this thesis, I report an important advancement in electro-plasmonic sensing techniques that utilizes nanohole-based devices and extraordinary light transmission effect. A bright-field configuration based electro-plasmonic nanohole arrays yields an extremely sensitive transducer of electric fields. Furthermore, these electro-plasmonic “nanoelectrodes” allow sub-millisecond temporal resolution without cross talk toneighboring nanoelectrodes as demonstrated in controlled experiments. Upon demonstrating the operation of this new configuration, the device was successfully used for large scale electrophysiological imaging of cardiomyocytes in vitro. Subsequently, I discuss electro-plasmonic nanoshell antennas as in vivo probes for detecting electrogenic cell activity in live animals with high-resolution. The sensitivity of these devices allows diffraction-limited resolution measurement without photobleaching and phototoxicity issues that typically plague genetically incorporated fluorescence reporters