Electronic Molecular Detection: from Proteins to Neurons

Thesis (Ph.D.)--University of Washington, 2014This dissertation presents my research investigating a number of microscale devices designed to interact with various biological systems. First, I describe the development of nanoscale electronic sensor devices for quantitative detection of biomolecule concentrations in liquids. Two sensor designs are discussed - one using semiconducting nanowires and another employing a novel fluid nanochannel layout. Microfabrication and sensor performance optimization methods are discussed, culminating with an overview of molecular sensing results. Second, I describe an effort undertaken in support of a project aimed at creating a contact lens based glucose sensor. A miniature version of the sensor was created and tested in-vivo, inside a rabbit's eye, using the intraocular fluid as an ersatz tear fluid. Also, described is an anatomically correct model of a human eye, complete with moving eyelids and working tear ducts, used for testing contact lens sensors in a life-like environment. This effort has helped focus further development of the contact lens sensor project on solving the issue of chemical interference in in-vivo environments. Lastly, I describe design, microfabrication and in-vivo testing of implantable, highly flexible, non-invasive active neural electrode arrays used in an effort to create a fully implantable and wirelessly powered brain-computer interface system. Multiple array geometries for both subcranial and intraspinal implantation as well as their in-vitro and in-vivo performance are discussed. Ultimately, I present an active electrode array assembled with four neural signal amplifiers, using a novel two-sided parylene process