Transcript 幻灯片 1 - Nc State University

MAE 589M Final Project
A novel neuromorphic micro robotic neural
probe
Riley Zeller-Townson
Haibo Zhao
Date: 12/09/2008
Project Overview
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Preformed literature Review
Found gap in current technology
Proposed design
Proposed fabrication method for design
Background
• Many applications for reading neuron
voltages (neuroprosthetics, stimulation)
• Neurons pass electrochemical signals to
each other
• Neurons connect using long, skinny
extensions (axons and dendrites)
History Lesson
• Need to be able to monitor minute electric,
chemical signals
• First experiments on squid giant axon (Cole,
Hodgkin)
• First real microelectrodes: hollow glass
tubes
• Teflon coated microwires
• Michigan Probes, Utah Arrays, SOI
Current Work
• Biocompatibility
– Surface coating
– Flexibility
– Probe geometry
• Microfluidics
– Deliver and sample
• Signal quality
Problem Definition
• No design that physically resembles a
neuron, though geometry a component of
biocompatibility
• Electrodes should be placed like synapses
on neuron
• Should be able to release chemical signals
(contain microfluidic channels)
• Electrodes/
microfluidics
on arms
(dendrites)
• Arms can
'grow' into
surrounding
tissue
• Arms stored
between
concentric
cyllinders
How it works
• Inner shaft acts as water main for
all microfluidic channels, connects
to each arm
• Drive actuators feed arms in and
out
• Arms bend and rotate around
inner shaft
Shuffle Drive Actuator
Actuator Dynamics
• EI (d4v(x))/(dx4) – S(d2v(x)/dx2) = 0
• v = Fel3 * (1 – cosh(k) – cosh(Kz) + zKsinh(K) + cosh(K(z-1)))/(EI 2
K3sinh(K))
• d = 2 ∫01 √(1+(dv/dx)2)dx -2l
• y = Fel3 /24EI (3 * 1/2K-tanh(1/2K)/(1/2K)3 )
Actuator Dynamics, cont
• Fe = ½ CV2 /d
• Voltage = Q/A(d1/ε1 + d2/ε2 + d3/ε3)
• Capacitance = Q/V = A/(d1/ε1 + d2/ε2 + d3/ε3)
• Capacitance = ε0A/d2
• d = (1/2 to 3/5) * ε0A *½ V2 /d2 *l3/(24EI) (3 *( 1/2K-tanh(1/2K))/(1/2K)3 )
Fabrication Process
Al deposition
Mask #1
Mask #2
Fabrication Process Continued
Parylene
deposition
Mask #3
Mask #5
Mask #6
Mask #4
Fabrication Process Continued
Photoresist
deposition
Parylene
deposition
Mask #7
Fabrication Process Continued
Platinum
Patterning
Thermal bonding
Electrode Isolation
Lifting off glass wafer
Parylene deposition on glass wafer
Fabrication Process Continued
Mask #8
Al etchmask patterning
Parylene etching
Fabrication Process Continued
Al etching
Photoresist
deposition
Fabrication Process Continued
Mask #9
Al etchmask
patterning
Photoresist etching
Fabrication Process Continued
Photoresist Etching
and Parylene Etching
Parylene deposition
Al etchmask
patterning
Release from silicon
mold by aluminum
dissolution
Fabrication Process Finished
Photoresist
dissolution
Conclusions
• Completed design that should incorporate
several biocompatibility techniques
• Created fabrication process for
sophisticated probe design
• More modeling necessary
• Some more specific dimensions
Thank you for your time
Any questions?