Progress in devices and materials for implantable multielectrode arrays

Abstract

The human brain comprises over 100 billion neurons that communicate with each other via electrical activities called action potentials. Sensory perception, cognition, and behavior all emerge from these activities. Neuroengineering is a developing interdisciplinary field that employs knowledge from neurobiology, electrical and electronic engineering, materials science and engineering, computer science, and many others. Neuroengineering aims to develop tools for understanding the mechanism of brain function at the circuit level, and to further the development of neuromodulation strategy and neuroprosthetics for motor, sensory, and mental rehabilitation from disabilities and illnesses. For high spatial and temporal resolution interfacing with neurons in the brain, implantable multielectrode arrays (MEAs) are a key member of the family of neuroengineering devices, which are designed and fabricated for in vivo electrophysiology, deep brain stimulation, and brain-computer interfaces (BCIs). On the one hand, action potential recording from MEAs can indicate the subject’s mental state and movement intentions, thus enabling the BCI technology to control external motor restoration devices such as robotic arms. On the other hand, neural stimulation electrodes can modulate abnormal neural activity and treat disorders like Parkinson’s disease, epilepsy, and depression. The physical and chemical properties of the electrodes, nanofabrication of arrays, and electrode-tissue interface materials are all important research subjects in translational neuroscience studies, and the utilization of nanomaterials and nanodevices continuously improves neural electrode technologies. At present, neural interface technology is confronting numerous challenges and opportunities, especially for in vivo neural circuit analysis, neuroelectronic medicine, and functional neuromodulation. The development of neural interface devices eagerly demands super-high-density, mesoscopic recording, minimal invasion, biosignal stability, and wireless interfacing. Achievement of these next-generation neural interface technology capabilities requires collaboration between neuroscientists, neurosurgeons, material scientists, microelectronic engineers, and many others.