Silicon optoelectronic microelectrodes with integrated oxygen sensors for brain-machine interfaces

In neural prosthetic systems, microelectrodes implanted in the brain record the electro-potentials elicited by specific thoughts and relay the signals to algorithms trained to translate the electrical activity into intended action. The authors describe novel elongated silicon optoelectronic neural electrodes that can record electrical signals and specific neural biomarkers. Specifically, the authors describe the integration of optical oxygen (O₂) sensors with silicon neural microelectrodes. The O₂ sensors are sol-gel derived xerogel thin films, that are coated on the exposed core of an optical fibre, that encapsulate O₂ responsive luminophores tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) in their porous structures. The electrodes were inserted into the trunk region of the somatosensory cortex and lowered into the barrel field of a rat. Oxygen and action potential recordings during whisker stimulation provide support for the potential utility of the device. The proposed optoelectronic neural electrodes, which can reach depths greater than 10 mm in the brain, could help the development of intelligent and more user-friendly neural prosthesis/brain machine interfaces as well as aid in providing answers to complex brain diseases and disorders.