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Building Neural Networks on
Carbon Nanotube Substrates
Weijian Yang
Department of Electrical Engineering and Computer Sciences
University of California, Berkeley, CA, 94720, USA
From Neuron to Neural Networks
 How do the neurons connect with each other to
form a network?
http://www.nih.gov/news/research_ma
tters/july2006/07142006gene.htm
3 um
http://www.joejoe.org/forum/i
ndex.php?showtopic=7945
150 um
 Ref. 1, 2
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
2
Outline
 1. Nano carbontubes boost neuronal electrical signaling
 Viviane Lovat, et.al. Nano Lett., 5, 1107, 2005.
 2. Engineering the neural network with patterned nano
carbontubes substrates.
 Tamir Gabay, et.al. Physica A, 350, 611, 2005.
 3. Outreach
 Understanding the brain, from neuron to mind. Harvard
Magazine, edited by Courtney Humphries, May 2009.
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Carbon Nanotubes as Substrates
 Why carbon nanotubes?
 Surface texture at the scale of ~10 to ~100 nm,
aspect ratio similar to the nerve fiber.
 High electrical conductivity.
 Strong mechanical strength.
 Chemical functionalization.
Good biocompatibility!
 Ref. 1-4
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Boost Neuronal Electrical Signal
 Hippocampal neuron growing on dispersed
MWCNT in culture medium.
 Ref. 1
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Boost Neuronal Electrical Signal
Spontaneous postsynaptic
current
Membrane potential
 Ref. 1
 Improve neural signal transfer.
 Increase network activity.
 Reinforce electrical coupling between neurons.
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Pattern the Neuron Network
catalyst
150 um
MWCNT
 Ref. 2
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Network Evolution
150 um
100 um
One hour after
cell deposition
After 96 hours
 Ref. 2
Neurons’ surface mobility and selective adhesion are the driving
mechanism for the well organized placement at the CNT sites.
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
8
Network Evolution
96 hours
A single link is formed
between the two nearest
neighbors.
128 hours
Connection is reinforced
with respect to time.
150 hours
A bundle is eventually
formed to establish a tensed
link between two islands.
150 um
 Ref. 2
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Summary
 Carbon nanotubes are highly biocompatible for
neural network. (surface morphology, electrical,
mechanical and chemical properties.)
 Well defined engineered cultured neural systems
can be formed on high density carbon nanotube
islands.
 A powerful platform to study neuronal adhesion,
neurite outgrowth, and the neural network.
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Outreach
 Nanowire is also a good candidate for the research into
neural network. (especially in electrical, chemical, and
biological signal detection.)
 Ref. 5, 6
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Reference
1. Viviane Lovat, et.al, “Nano Carbontubes Boost Neuronal Electrical Signaling,” Nano
Lett., 5, 1107, 2005.
2. Tamir Gabay, et.al, “Engineering the Neural Network with Patterned Nano Carbontubes
Substrates,” Physica A, 350, 611, 2005.
3. Miguel A. Correa-Duarte, et. al, “Fabrication and Biocompatibility of Carbon NanotubeBased 3D Networks as Scaffolds for Cell Seeding and Growth,” Nano Lett., 4, 2233,
2004.
4. Hui Hu, et. al., “Chemically Functionalized Carbon Nanotubes as Substrates for
Neuronal Growth,” Nano Lett., 4, 507, 2004.
5. Fernando Patolsky, et. al. “Detection, Stimulation, and Inhibition of Neuronal Signals
with High-Density Nanowire Transistor Arrays,” Science, 313, 1100, 2006.
6. “Understanding the brain, from neuron to mind,” Harvard Magazine, edited by Courtney
Humphries, May 2009.
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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Thank you!
Thank you!
UC Berkeley
EE 235 Presentation 2 Weijian Yang
May 4, 2009
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