Magnetic Actuation of Flexible Microelectrode Arrays for Neural Activity Recordings

Implantable microelectrodes that can be remotely actuated via external fields are promising tools to interface with biological systems at a high degree of precision. Here, we report the development of flexible magnetic microelectrodes (FM mu Es) that can be remotely actuated by magnetic fields. The FM mu Es consist of flexible microelectrodes integrated with dielectrically encapsulated FeNi (iron-nickel) alloy microactuators. Both magnetic torque- and force-driven actuation of the EM mu Es have been demonstrated. Nanoplatinum-coated FM mu Es have been applied for in vivo recordings of neural activities from peripheral nerves and cerebral cortex of mice. Moreover, owing to their ultrasmall sizes and mechanical compliance with neural tissues, chronically implanted FM mu Es elicited greatly reduced neuronal cell loss in mouse brain compared to conventional stiff probes. The FM mu Es open up a variety of new opportunities for electrically interfacing with biological systems in a controlled and minimally invasive manner.