Chemical and Biological Engineering ETDs

Publication Date

2-1-2012

Abstract

The generation of new three-dimensional (3D) matrices that enable integration of biomolecular components and whole cells into device architectures, without adversely altering their morphology or activity, continues to be an expanding and challenging field of research. This research is driven by the promise that encapsulated biomolecules and cells can significantly impact areas as diverse as biocatalysis, controlled delivery of therapeutics, environmental and industrial process monitoring, early warning of warfare agents, bioelectronics, photonics, smart prosthetics, advanced physiological sensors, portable medical diagnostic devices, and tissue/organ replacement. This work focuses on the development of a fundamental understanding of the biochemical and nanomaterial mechanisms that govern the cell-directed assembly and integration process. It was shown that this integration process relies on the ability of cells to actively develop a pH gradient in response to evaporation induced osmotic stress, which catalyzes silica condensation within a thin 3D volume surrounding the cells, creating a functional bio/nano interface. The mechanism responsible for introducing functional foreign membrane-bound proteins via proteoliposome addition to the silica-lipid-cell matrix was also determined. Utilizing this new understanding, 3D cellular immobilization capabilities were extended using sol-gel matrices endowed with glycerol, trehalose, and media components. The effects of these additives, and the metabolic phase of encapsulated S. cerivisiase cells, on long-term viability and the rate of inducible gene expression was studied. This enabled the entrapment of cells within a novel microfluidic platform capable of simultaneous colorimetric, fluorescent, and electrochemical detection of a single analyte, significantly improving confidence in the biosensor output. As a complementary approach, multiphoton protein lithography was utilized to engineer 3D protein matrices in which to integrate cells and direct their behaviors. This process permits, for the first time, the selection and in situ isolation of a single target cell from a population of cells with mixed phenotypes, and the subsequent monitoring of its behavior, and that of its progeny, under well defined conditions. These techniques promise a new means to integrate biomolecules with nanostructures and macroscale systems, and to manipulate cellular behavior at the individual cell level, having significant implications towards development of practical and robust integrated cellular systems.

Keywords

sol-gel bioencapsulation, cell-based biosensors, living hybrid biomaterials, cell-directed integration, glycerol modified silanes, orthogonal biodetection; Microencapsulation., Nanostructured materials., Biosensors.

Sponsors

Funding for this work from the Defense Treat Reduction Agency (DTRA) Chemical and Biological Basic Research Program (grant B084467I) and the Sandia National Laboratories Lab Directed Research and Development (LDRD) Program are gratefully acknowledged.

Document Type

Dissertation

Language

English

Degree Name

Chemical Engineering

Level of Degree

Doctoral

Department Name

Chemical and Biological Engineering

First Committee Member (Chair)

Brozik, Susan M.

Second Committee Member

Lopez, Gabriel P.

Third Committee Member

Werner-Washburne, Margaret

Fourth Committee Member

Atanassov, Plamen

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