Alexandria Digital Research Library

Development of Advanced Electrochemical Sensors for DNA Detection at the Point of Care

Author:
Hsieh, Kuangwen
Degree Grantor:
University of California, Santa Barbara. Mechanical Engineering
Degree Supervisor:
H. Tom Soh
Place of Publication:
[Santa Barbara, Calif.]
Publisher:
University of California, Santa Barbara
Creation Date:
2012
Issued Date:
2012
Topics:
Nanotechnology, Engineering, Biomedical, Chemistry, Biochemistry, and Engineering, Mechanical
Keywords:
Electrochemistry
Biosensor
DNA
Microfluidics
Point-of-care
Genres:
Dissertations, Academic and Online resources
Dissertation:
Ph.D.--University of California, Santa Barbara, 2012
Description:

In the post-genomic era, ever-advancing capabilities in DNA detection and analysis have become vital to the detection of infectious diseases and the diagnosis of genetic abnormalities and inheritable diseases. The benefit of such capabilities, however, has yet to reach patients outside of centralized facilities. There thus exists an increasing need to decentralize DNA detection methods and to administer such diagnostics at the "point of care." Electrochemical-based DNA sensors present a compelling approach, but have yet to deliver satisfactory sensitivity, specificity, miniaturization, and real-time monitoring capability to meet the demand of point-of-care diagnostics. Motivated by their potential and their current limitations, in this dissertation, we present a series of strategies that we have undertaken in order to address the key shortcomings of electrochemical DNA sensors and advance them toward point-of-care applications.

First, we report a single-step, single reagent, label-free, isothermal electrochemical DNA sensor based on the phenomenon of enzyme catalyzed target recycling amplification. Using this technique, we achieve improved detection limit in comparison to hybridization-based sensors without amplification. We also demonstrate greater than 16-fold amplification of signal at low target concentrations.

Next, we present a novel electrochemical DNA sensor that detects single-nucleotide mismatched targets with unprecedented "polarity-switching" responses. This "bipolar" sensor employs a surface-bound and redox-modified (methylene blue) DNA probe architecture, and outputs a decreased Faradaic current when hybridized to a perfectly matched (PM) target, but conversely reports an increased Faradaic current when hybridized to a single-base mismatched (SM) target.

Third, we describe the microfluidic electrochemical dynamic allele specific hybridization (microE-DASH) platform for versatile and rapid detection of single-nucleotide polymorphisms. Implementing electrochemical-based melting curve analysis within the microfluidic device, this platform directly detects PCR amplicon-like targets and distinguishes perfectly matched target from single-base mismatched target and heterozygote combination of both targets in 20 minutes.

Finally, we present the microfluidic electrochemical quantitative loop-mediated isothermal amplification (MEQ-LAMP) platform for rapid, sensitive, and quantitative detection of pathogen genomic DNA at the point of care. DNA amplification is electrochemically monitored in real time within a monolithic microfluidic device, enabling the detection of as few as 16 copies of Salmonella genomic DNA via a single-step process in under an hour.

Physical Description:
1 online resource (180 pages)
Format:
Text
Collection(s):
UCSB electronic theses and dissertations
ARK:
ark:/48907/f31v5bwd
ISBN:
9781267294517
Catalog System Number:
990037518610203776
Rights:
Inc.icon only.dark In Copyright
Copyright Holder:
Kuangwen Hsieh
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