Microelectrode Arrays for Clinical Mapping: Considerations and Brain - PowerPoint PPT Presentation

Microelectrode Arrays for Clinical Mapping: Considerations and Brain Recordings with 1024 Channel Arrays A subset of slides presented in the symposium has been removed pending publication Shadi A. Dayeh Integrated Electronics and Biointerfaces Lab Department of Electrical and Computer Eng. University of California San Diego sdayeh@eng.ucsd.edu http://iebl.ucsd.edu/ 1

Brain Electrodes and Brain Signals Brain-penetrating microelectrodes Brain-surface electrodes EEG sensors Coverage (cm) LFPs Intracellular 10 mV Resolution (μm) potentials 100 ms Steriade et al. J. Physiology, 2001 2 After Nitish Thakur, Science Translational Medicine 5, 210ps17, 2013.

Use of Brain Mapping Devices 1. Diagnostic: Clinical Mapping During 2. Therapeutic: Neuroprosthesis; Cortical Neurosurgery Interface prothesis - Motor function disability - Intractable epilepsy à delineation of the - Speech disorders, etc. epileptic zone - Tumor resection Utah array Hochberg et al., Nature 485, 372, 2012. Movement disorders (Parkinson’s disease) 3 https://www.neurologyadvisor.com

State of the art Brain Electrodes 4

Neuralink: An integrated brain-machine interface platform with thousands of channels - Developing ultra-high bandwidth brain-machine interfaces. - Elon Musk: Goal is to achieve “symbiosis with artificial intelligence.” - Silent speech communications. Implanter robot Threads Implanted in a mouse cortex Mouse preparation Device Assembly Human trials are expected in Fall of 2020. 5

Silent Communication “Speech disorders” Dr. Edward Chang, UCSF Dr. Edward Chang, UCSF Nature 568, 493, 2019 Facebook A diffuse optical tomography headset Concept is to use near-infrared light to measure • oxygen saturation levels in the brain. By mapping blood oxygen levels to specific • brain regions, phonemes, or intent for motor movements could be decoded. 6

State of the Art Clinical Mapping Device AdTech Inc., 256 ch clinical grid 6.4 cm 1.17 mm 4 mm These large electrodes under-sample the brain activity à Smaller contacts But scaling metal for high spatiotemporal resolution! electrodes to smaller diameters for better spatial resolution compromises their recording ability. 7 Nature 568, 493, 2019

Thin Electrodes: • Compliant • Conformal. • Intimate contact. 8

Why Impedance Matters for Recording 1. High spatial resolution à scaling à noise 2. Large area coverage à parasitic shunting à attenuation 5 10 D ( µ µ m) 1/2 ) Planar Pt 4 10 Noise Voltage ( µ V/Hz 20 3 10 2 C p 10 60 1 10 200 0 10 500 -1 10 1000 -2 10 -3 10 0.1 1 10 100 1000 Z E Frequency (Hz) 5 10 1/2 ) CPE PEDOT/Pt 4 10 Noise Voltage ( µ V/Hz V in R s 3 V s 10 Low impedance overcomes 1/f noise Z amp 2 C p 10 D ( µ m) R ct C ad 1 10 20 60 200 1000 500 0 10 Ref -1 % &'( 10 ! "# = )*+ ( % , -. -% , ! / -2 10 % &'( -3 10 0.1 1 10 100 1000 If C p is large , Z E should be small Frequency (Hz) Ganji et al. Adv. Func. Mat. 27, 1703018, 2017 Neto et. al. Front Neurosci. 12, 715, 2018

‘Everything is the Interface’: Electrodes Volcano Plot: Electrochemical activity vs. bond energy - + - + - + + - + + + + capacitive Faradaic (redox) PEDOT:PSS SIROF Eick et al., 6 th Int. MEA meeting, 2008 Rivnay et al. Nat. Com. 7, 11287, 2016 + - - + - + - + - + + + + - + + + - + + - + - + + + Trasatti et al. J. Electroanalytical Chemistry 39, 163, 1972. Surface catalytic property and surface area are both important. 10

Outline v Pt Nanorod (PtNR) surface microelectrode arrays. • Structure and electrochemical properties. v Intraoperative Monitoring: • Epilepsy monitoring. • Language mapping. • Functional boundaries. v Spinal Cord Implants for Pain and Restoring Motion. 11

1D Materials on Flexible Substrates T>400C 1 µm This work: Pt nanorods Harmand et al. Phys. Rev. Lett. 121 , 166101, 2018 12

Pt Nanorod Electrodes • Dealloying: Selective dissolution of alloys to a stable nanoporous structure. J. Erlebacher et al. Nature 410, 450, 2001. 13

Pt Nanorod Electrodes SEM 20 μm 5 μm M. Ganji et al. Nano Lett. 19, 6244, 2019. 14

PtNR Pt Cr Parylene C 15

" ! " 1 ! " 1 1 ! "$$ # #$$ 2.26 Å (111) Pt " 1 ! " " ! 11 ! [ $!! ] Pt (g) "! " 1 ! " 1 1 ! "$$ # #$$ " 1 ! " ! " 11 ! 2.26 Å [01 ! ] Pt (111) Pt (h) " 1 1 ! 2.26 Å " 1 ! " 1 nm ! 5 nm (111) Pt [01 ! ] Pt 16

Electrochemical Properties of PtNRs PtNR Pt PEDOT:PSS/Pt 15 1.0 D = 50 µm 8 10 10 transient (V) 0.5 P t N 5 current (µA) R Voltage 0.0 10 Hz Injected 0 12MΩ -0.5 Pt -5 -1.0 7 10 -10 -1.5 |Power| ( µ W) 20 1 1.6MΩ |Z| (10 Hz) ( W ) 15 6 10 10 1.1MΩ 5 0 5 10 0.0 0.5 1.0 1.5 2.0 2.5 Time (ms) e) 4 t c = t a =650μs; E ipp =max possible 10 10 Current-injection limit ( µ A) 3 10 40μm 20 100 1000 16X 11X CIC (mC/cm 2 ) Diameter (µm) - Low impedance à low noise and 1 better stimulation characteristics. - Smaller voltage transients on PtNRs à Lower power dissipation for an implant that uses PtNRs. 0.1 17 20 40 60 80 100 120 140 160 M. Ganji et al. Nano Lett. 19, 6244, 2019. Diameter ( µ m)

Intraoperative Neuromonitoring Audio / video and automated object tracking 18 Nat Neurosci 21, 1281–1289, 2018 Video courtesy of Hersh Kanner and Jessica Chang

Small Pitch μECoG Array 50μm 30μm 19

Recording Traveling Waves from the Human Brain 20 Angelique Paulk et al., submitted, 2019.

Interictal Discharges (IID) in Epilepsy Patients: Spontaneous IID Traveling Waves IIDs seen on both recording systems Two 6-channel clinical strips PEDOT Jimmy Yang et al., in preparation, 2019.

Events seen similarly by each recording system – Interictal Discharges (IIDs) IIDs seen on both recording systems Time (s) 22 Time (s) Jimmy Yang et al., in preparation, 2019.

Interictal Discharges (IID) in Epilepsy Patients: Spontaneous IID Traveling Waves 128 500 400 300 200 Voltage (μV) 100 0 -100 -200 -300 1 128 -400 1 1.8 1.6 2 2.2 1.7 1.9 2.1 2.3 1.5 2.4 2.5 Time (s) 23 Jimmy Yang et al., in preparation, 2019.

Intraoperative Recording at UCSD/MGH Dr. Ahmed Raslan, OHSU Youngbin Tchoe Jihwan Lee Andrew Bourhis Jeff Gertsch Sharona Ben-Haim Joseph Ciacci Joel Martin Neurology, UCSD Neurosurgery MD Neurosurgery, UCSD Neurosurgery, UCSD Chief Neurophysiologist Epilepsy and Pain Neurooncology & ECE PhD in progress & experiment design management & experiment design Implant/experiment experiment design design 24

Acknowledgment Fabrication in SDNI, NSF-NNCI site @ UCSD NSF CAREER NSF SNM (CMMI) NSF ECCS/DMR (as of Sept. 2019) This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. 25

Massachusetts General Hospital: • UC San Diego: Thanks to: • Sydney Cash • Eric Halgren • Angelique Paulk • Sharona Ben-Haim • Dan Cleary • Jimmy Yang • Charles Dickey • Yangling Chou • Erik Kaestner • Dan Soper • Vikash Gilja • Ziv Williams • Ian Galton • Daniel Cahill • Vincent Leung • Brian Nahed • Joel Martin • Pamela Jones • The fantastic and patient OR staff • Douglas Maus • Timothy Gentner • Mirela Simon • Nasim Vahidi • Ezequiel Arneodo • Aaron Tripp and the IOM team • IEBL Lab Members at UCSD: • Scot Mackeil • Mehran Ganji • Scott Farren • Lorraine Hossain • The fantastic and patient OR staff brain • Hongseok Oh Brigham and Women’s Hospital • Yun Goo Ro • Garth Rees Cosgrove • Sang Heon Lee spine • Jung Woo Lee • Samantha Russman • Melissa Murphy • Andrew Bourhis • Li Chen 1024 arrays • Ritwik Vatsyayan • Susan Lovell • Youngbin Tchoe nanowire • The fantastic and patient OR staff • Jihwan Lee 26 • Ren Liu