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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

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UC Berkeley2EE 235 Presentation 2 Weijian Yang May 4, 2009 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 http://www.joejoe.org/forum/i ndex.php?showtopic=7945 Ref. 1, 2 3 um 150 um

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UC Berkeley3EE 235 Presentation 2 Weijian Yang May 4, 2009 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.

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UC Berkeley4EE 235 Presentation 2 Weijian Yang May 4, 2009 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

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UC Berkeley5EE 235 Presentation 2 Weijian Yang May 4, 2009 Boost Neuronal Electrical Signal Hippocampal neuron growing on dispersed MWCNT in culture medium. Ref. 1

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UC Berkeley6EE 235 Presentation 2 Weijian Yang May 4, 2009 Boost Neuronal Electrical Signal Improve neural signal transfer. Increase network activity. Reinforce electrical coupling between neurons. Spontaneous postsynaptic current Membrane potential Ref. 1

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UC Berkeley7EE 235 Presentation 2 Weijian Yang May 4, 2009 Pattern the Neuron Network catalyst 150 um MWCNT Ref. 2

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UC Berkeley8EE 235 Presentation 2 Weijian Yang May 4, 2009 Network Evolution One hour after cell deposition After 96 hours Neurons surface mobility and selective adhesion are the driving mechanism for the well organized placement at the CNT sites. Ref. 2 100 um 150 um

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UC Berkeley9EE 235 Presentation 2 Weijian Yang May 4, 2009 Network Evolution 96 hours 128 hours 150 hours A single link is formed between the two nearest neighbors. Connection is reinforced with respect to time. A bundle is eventually formed to establish a tensed link between two islands. Ref. 2 150 um

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UC Berkeley10EE 235 Presentation 2 Weijian Yang May 4, 2009 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.

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UC Berkeley11EE 235 Presentation 2 Weijian Yang May 4, 2009 Outreach Nanowire is also a good candidate for the research into neural network. (especially in electrical, chemical, and biological signal detection.) Ref. 5, 6

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UC Berkeley12EE 235 Presentation 2 Weijian Yang May 4, 2009 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 Nanotube- Based 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.

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UC Berkeley13EE 235 Presentation 2 Weijian Yang May 4, 2009 Thank you!