Neuroscientists have long recognized the significance of using microelectrode arrays for recording extracellular potentials from populations of neurons, for which a number of such devices have been developed so far. However, current implantable microelectrode technologies to monitor single neuronal function in-vivo often fail in chronic situations, likely due to mechanical drift in positioning mechanisms, micromotion of brain tissue and gliosis around the implant site. The overall goal of the proposal is to develop a reliable technology for recording electrical potentials from single neurons in chronic experiments. We propose to develop a novel microfabricated thermal microactuator and associated microelectrode technology in collaboration with Sandia National Laboratories to enable repositioning of microelectrodes after implantation. The flexibility to reposition the microelectrodes after implantation (in the event of a failure or otherwise) using microactuators will potentially increase the reliability and consistency of single-neuronal recordings in-vivo in chronic experiments with awake and behaving animals. The key goals for developing this technology in this proposal are (a) to enable high quality, reliable single- unit electrical recordings from ensembles of neurons even in deep structures of the brain in awake, behaving rodents (b) to enable reliable positioning and repositioning of microelectrodes in both acute and long-term experiments and (c) assess the effect of microelectrode movement on the surrounding brain tissue. We will use a combination of modeling and simulation, novel microfabrication and packaging techniques, bench-top testing and in-vivo testing approaches for design, characterization and validation. Besides leading to novel discoveries in our own research into neuronal mechanisms of stroke injury and recovery, this new technology will immediately impact several NIH funded grants of our collaborators. The microactuated microelectrode will be tested in a scenario that demands accurate long-term recording from neurons in deep nuclei of the brain. Independent evaluation and dissemination will be ensured with the help of collaborators doing in vivo experiments for understanding the mechanisms of memory retrieval and consolidation and memory deficits in aging, auditory physiology, cortical prostheses etc.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Special Emphasis Panel (ZRG1-MDCN-K (50))
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Ludwig, Kip A
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Arizona State University-Tempe Campus
Engineering (All Types)
Schools of Engineering
United States
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Anand, Sindhu; Kumar, Swathy Sampath; Muthuswamy, Jit (2016) Autonomous control for mechanically stable navigation of microscale implants in brain tissue to record neural activity. Biomed Microdevices 18:72
Sridharan, Arati; Nguyen, Jessica K; Capadona, Jeffrey R et al. (2015) Compliant intracortical implants reduce strains and strain rates in brain tissue in vivo. J Neural Eng 12:036002
Sridharan, Arati; Rajan, Subramaniam D; Muthuswamy, Jit (2013) Long-term changes in the material properties of brain tissue at the implant-tissue interface. J Neural Eng 10:066001
Anand, Sindhu; Sutanto, Jemmy; Baker, Michael S et al. (2012) Electrothermal Microactuators With Peg Drive Improve Performance for Brain Implant Applications. J Microelectromech Syst 21:1172-1186
Sutanto, Jemmy; Anand, Sindhu; Sridharan, Arati et al. (2012) Packaging and Non-Hermetic Encapsulation Technology for Flip Chip on Implantable MEMS Devices. J Microelectromech Syst 21:882-896
Sutanto, Jemmy; Anand, Sindhu; Patel, Chetan et al. (2011) Novel First-Level Interconnect Techniques for Flip Chip on MEMS Devices. J Microelectromech Syst 21:132-144
Jackson, Nathan; Sridharan, Arati; Anand, Sindhu et al. (2010) Long-Term Neural Recordings Using MEMS Based Movable Microelectrodes in the Brain. Front Neuroeng 3:10
Saha, Rajarshi; Jackson, Nathan; Patel, Chetan et al. (2010) Highly doped polycrystalline silicon microelectrodes reduce noise in neuronal recordings in vivo. IEEE Trans Neural Syst Rehabil Eng 18:489-97
Jackson, Nathan; Muthuswamy, Jit (2009) Flexible Chip Scale Package and Interconnect for Implantable MEMS Movable Microelectrodes for the Brain. J Microelectromech Syst 18:396-404
Stice, Paula; Muthuswamy, Jit (2009) Assessment of gliosis around moveable implants in the brain. J Neural Eng 6:046004

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