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Wireless Nano and Molecular Scale Neural Interfacing


Sadek, Akram Sarwat (2017) Wireless Nano and Molecular Scale Neural Interfacing. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9RJ4GG4.


Nanoscale circuits and sensors built from silicon nanowires, carbon nanotubes and other devices will require methods for unobtrusive interconnection with the macroscopic world to fully realise their potential; the size of conventional wires precludes their integration into dense, miniature systems. The same wiring problem presents an obstacle in our attempts to understand the brain by means of massively deployed nanodevices, for multiplexed recording and stimulation in vivo. We report on a nanoelectromechanical system that ameliorates wiring constraints, enabling highly integrated sensors to be read in parallel through a single output. Its basis is an effect in piezoelectric nanomechanical resonators that allows sensitive, linear and real-time transduction of electrical potentials. We interface multiple signals through a mechanical Fourier transform using tuneable resonators of different frequency and extract the signals from the system optically. With this method we demonstrate the direct transduction of neuronal action potentials from an extracellular microelectrode. We further extend this approach to incorporate nanophotonics for an all-optical system, coupled via a single optical fibre. Here, the mechanical resonators are both driven and probed optically, but modulated locally by the voltage sensors via the piezoelectric effect. Such piezophotonic nanoelectromechanical systems may be integrated with nanophotonic resonators, allowing concordant multiplexing in both the radiofrequency and optical bandwidths. In principle, this would allow billions of sensor channels to be multiplexed on an optical fibre. With view to eventually integrating such technology into a neural probe, we develop fabrication methods for crafting wired silicon neural probes via photolithography and electron beam lithography. Finally, to complement recording, we propose novel ideas for wireless, multiplexed neural stimulation through the use of radiofrequency-sensitive molecular scale resonators.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:multiplexing; NEMS; neural probe; scalable neural recording; nanophotonics; fibre optics; wireless; piezoelectric
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Scherer, Axel
Group:Kavli Nanoscience Institute
Thesis Committee:
  • Burdick, Joel Wakeman (chair)
  • Andersen, Richard A.
  • Choo, Hyuck
  • Scherer, Axel
Defense Date:16 August 2016
Funding AgencyGrant Number
Record Number:CaltechTHESIS:12162016-094948729
Persistent URL:
Related URLs:
URLURL TypeDescription related to ch. 2 DocumentArticle related to thesis content
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9996
Deposited By: Akram Sadek
Deposited On:21 Mar 2017 18:00
Last Modified:04 Oct 2019 00:14

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