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Silicon Neural Probes for Stimulation of Neurons and the Excitation and Detection of Proteins in the Brain


Fowler, Trevor Michael (2019) Silicon Neural Probes for Stimulation of Neurons and the Excitation and Detection of Proteins in the Brain. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2kvw-ad56.


This thesis describes the development of a number of novel microfabricated neural probes for a variety of specific neuroscience applications. These devices rely on single mode waveguides and grating couplers constructed from silicon nitride thin films, which allows the use of planar lightwave circuits to create advanced device geometries and functions. These probes utilize array waveguide gratings to select an individual emitter from a large array of emitters using the wavelength of incoming light, allowing for spatial multiplexing of optical stimulation. These devices were tested in the laboratory and in living tissue to verify their efficacy. This technology was then modified to create steerable beam forming for stimulation of neurons using optical phase arrays. This technology was also tested for use in fluoresence lifetime imaging microscopy and the first application of pulsed light through the photonic circuits. Finally, this technology was again modified to create laminar illumination patterns for light sheet fluorescence microscopy applications. These devices were further improved by adding embedded microfluidics to the probes. The process of creating embedded microfluidic channels by the dig and seal method is described in detail, including modifications to the procedure that were added to address potential pitfalls in the fabrication process. Next, two projects which combine microfluidics with the optical devices described in the previous chapter are detailed. One project involves combining the use of optical emitters with microfluidic injections containing caged neurotransmitters to stimulate neurons is described. The other project involves microfluidic sampling of the extracellular space for neuropeptides which are detected using ring resonator biosensors. The sensitivity of these biosensors was analyzed in detail, determining both the physical limit of detection and the effect of biological noise due to non-specific binding on the sensors.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Neural Probes; Neural Implants; Silicon Microfluidics; Photonics; Optogenetics
Degree Grantor:California Institute of Technology
Division:Biology and Biological Engineering
Major Option:Bioengineering
Thesis Availability:Not set
Research Advisor(s):
  • Roukes, Michael Lee
Thesis Committee:
  • Faraon, Andrei (chair)
  • Roukes, Michael Lee
  • Yang, Changhuei
  • Lester, Henry A.
  • Moreaux, Laurent C.
Defense Date:27 August 2018
Non-Caltech Author Email:tmfowler (AT)
Record Number:CaltechTHESIS:09172018-140652131
Persistent URL:
Related URLs:
URLURL TypeDescription ItemUS patent application US20170106204A1 ItemUS patent application US20140142664A1 ItemArticle adapted for chapter 4.
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11185
Deposited By: Trevor Fowler
Deposited On:09 Oct 2018 18:54
Last Modified:25 May 2021 22:26

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