High-density CMOS Bioelectronic Chip

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Direktes Ankoppeln von Hirnzellen an Mikroelektronik 20 μm 50 m Andreas

action potentials measurements of electric activity CMOS Bioelectronics CMOS,

bioelectronic i chips High-density CMOS Bioelectronic Chip high-density

1 Direktes Ankoppeln von Hirnzellen an Mikroelektronik 20 μm 50 m Andreas Hierlemann Slide 1 Outline Bioelectronics Fundamentals electrogenic cells action potentials measurements of electric activity CMOS Bioelectronics CMOS, why CMOS? bioelectronic i chips High-density CMOS Bioelectronic Chip high-density electrode realization circuitry, system and packaging Cell Recordings single-cell localization in slices tracing of axonal signal propagation Andreas Hierlemann Slide 2

Interfacing Cells with Microelectronics Physiological

and charge transport Na +,K + ion mobility: 5.2 7.

Cells 20 m Human brain: 10 12 neurons Neuron connected

(K +, Na + ) Neuronal communication: electric signals,

2 Interfacing Cells with Microelectronics Physiological electrolyte solution Electro-active cell Ionic species and charge transport Na +,K + ion mobility: x10-8 m 2 /Vs Electrode Microelectronics or CMOS chip Electrons,, mobility in Si: 0.15 m 2 /Vs Andreas Hierlemann Slide 3 Neurons or Brain Cells 20 m Human brain: neurons Neuron connected to more than 1000 others Neurons: electro-active cells (K +, Na + ) Neuronal communication: electric signals, action potentials chemical signals between cells (synapses) Andreas Hierlemann Slide 4

3 Neurons µm axon hillock axon µm dendrites cell body action potential axon terminals input integration signal conduction output Andreas Hierlemann Slide 5 Membrane Potential Cytosol Extracellular fluid 140 mm K + 4 mm K + K + channel Channels: - + voltage-gated Na + channel 12 mm Na mm Na + Cl - channel 4 mm Cl mm Cl mm A - 34 mm A - Cell resting potential about -70mV, mainly due to open K + -channels Andreas Hierlemann Slide 6

Action Potential Ion permeab bility [mmo ol/cm 2 ] Na +

Slide 7 Standard Method: Patch Clamp Patch Clamp +

Single ion channels - Invasive method - Reduced life time -

4 Action Potential Ion permeab bility [mmo ol/cm 2 ] Na + permeability K + permeability time [ms] Andreas Hierlemann Slide 7 Standard Method: Patch Clamp Patch Clamp + Transmembrane measurement I / V + Action potential: 100 mv PP + Single ion channels - Invasive method - Reduced life time - Limited number of cells Neuron Adapted from: Lodish et al Andreas Hierlemann Slide 8

5 Extracellular Recording Ion channels Intracellular signal Electrogenic Cell I Na I K 1 ms mv CMOS chip Sensor Area Gap Passivation Circuitry 100 μv V 1 ms Extracellular signal Andreas Hierlemann Slide 9 Microelectronics Technology: Complementary Metal Oxide Semiconductor (CMOS) Intermetal oxide Passivation Metal 2 Nitride Metal 1 Polysilicon Materials: S n-well PMOS p-silicon substrate D D S n+ Gate Contact oxide oxide p+ NMOS Field oxide Silicon substrate Doped silicon Polysilicon Silicon oxide layers Silicon nitride layers Aluminum metal Biocompatibility! Andreas Hierlemann Slide 10

Connectivity On-chip multiplexing, signals from 10 000 transducers via few connections Capability of massively parallel or multi-parameter detection Usability Standard interfaces and data handling,

6 Why CMOS or Microelectronics Technology? Signal Quality On-chip signal conditioning close to signal source, enabling function: Miniaturization ation without t performance loss Capability to handle small feature size and minute signals Connectivity On-chip multiplexing, signals from transducers via few connections Capability of massively parallel or multi-parameter detection Usability Standard interfaces and data handling, experimental protocols High-performance systems (standalone) that are easy to use (nonexperts) Standard Semiconductor Technology (CMOS) Andreas Hierlemann Slide 11 High-Density Electrode Arrays Why high electrode density? Details of signal evolution Subcellular resolution Dynamics on network level How to achieve (sub)-cellular resolution Constraining the cells High-density electrode array G. Zeck et al., PNAS, 2001 A. Lambacher et al., Applied Phys A, 2004 Andreas Hierlemann Slide 12

High-Density Chip Micrograph High-density electrodes High-performance

khz 126 Electrodes simultaneously readable from 11 016 Chip size: 71x65mm 7.

steps Transmitter HP: 0.3Hz, first order 3.

20kHz/channel frame counter, CRC DAC: 8b (stimulation) Receiver Supply: 3.

7 High-Density Chip Micrograph High-density electrodes High-performance electronics Electrode pitch: 17 µm Electrode diameter: 7 µm Sampling at 20 khz 126 Electrodes simultaneously readable from Chip size: 71x65mm Andreas Hierlemann Slide 13 Chip Schematic Gain: in 18 steps Transmitter HP: 0.3Hz, first order 3.2MHz, 9b LP: 4kHz 14kHz, second order MUX, ADC control ADC: 8b, SA, 20kHz/channel frame counter, CRC DAC: 8b (stimulation) Receiver Supply: 3.3V (digital), 5V (analog) serial decode commands CMOS: 0.6µm, 3M2P configure array, settings Andreas Hierlemann Slide 14

8 Fabricated & Packaged System Cultivation time: Months Re-usable Andreas Hierlemann Slide 15 Rat Acute Parasagittal Cerebellar Slice 2 mm Long-Evans rat slice 1.8 mm Cooperation: o Prof. U. Egert, University of Freiburg, D Andreas Hierlemann Slide 16

9 Electrical Activity Map Spontaneous activity x Probed electrodes Events detected with a threshold of ±36 µv and an event rate of: 0.2 Hz 1 Hz 1H Hz 10 Hz 10 Hz 100 Hz > 100 Hz Andreas Hierlemann Slide 17 Acute Brain Slices: Spike Traces Long-Evans rat Parasagittal cerebellar slice Spontaneous activity Andreas Hierlemann Slide 18

Spike Sorting Assign events according to signal shape to different neurons

Output: - time stamps - spike-triggered averages, footprints Andreas

Potential Andreas Hierlemann Slide 20 Center of negative peaks

10 Spike Sorting Assign events according to signal shape to different neurons High electrode density allows to apply Independent Component Analysis (ICA) Output: - time stamps - spike-triggered averages, footprints Andreas Hierlemann Slide 19 Purkinje Cell: Extracellularly Measured Action Potential Andreas Hierlemann Slide 20 Center of negative peaks Equipotential at half min. peak (-63 µv) Center of positive peaks Equipotential at half max. peak (18 µv)

11 Localization of Identified Cells Andreas Hierlemann Slide 21 Temporal Evolution of Action Potential Dynamic evolution of measured action potential ti Current sources / sinks Andreas Hierlemann Slide 22

12 Temporal Evolution of Action Potential Current sources / sinks Action potential: ~ 0.6 ms Andreas Hierlemann Slide 23 High-Density Chip: Dissociated Neurons 3200 Electrodes per mm 2 Pitch: 17 µm Electrode Ø: 7 µm DRG neurons (DIV 2) 10 μm Andreas Hierlemann Slide 24

13 Elicited Activity upon Stimulation Andreas Hierlemann Slide 25 Summary CMOS suitable technology platform to interface with living i cells Chips function in biological environment and vice versa Important features: (1) Signal quality: Signal conditioning, A/D conversion on chip (2) Connectivity: Multiplexing to overcome interconnection limitation (3) Ease of use due to integrated t functionality Bioelectronic systems High temporal and spatial resolution recording capabilities Recording of physiological details at sub-cellular resolution and, at the same time, at network level (dynamic configuration in 1 ms) Use: Fundamentals of information processing or pharmacological testing Andreas Hierlemann Slide 26

A CMOS-based Tactile Sensor for Continuous Blood Pressure Monitoring

A CMOS-based Tactile Sensor for Continuous Blood Pressure Monitoring K.-U. Kirstein 1, J. Sedivy 2, T. Salo 1, C. Hagleitner 3, T. Vancura 1, A. Hierlemann 1 1 : Physical Electronics Laboratory, ETH Zurich,