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Advancements in Self-Assembled Monolayer-Based Sensing and Surface Modification Technologies
Abstract
Recently developed biosensors have demonstrated high sensitivity, specificity, and selectivity. Among these, self-assembled monolayer (SAM)-based sensors have gained substantial popularity in the past decades, owing to their unique properties, including the range of compatible substrates, functionalization methods, and recognition elements. This thesis reports several advancements in SAM-based sensing and surface modification technologies. Chapter 1 provides a brief introduction to the discussed concepts.Chapter 2 reports the use of short peptides in the design and fabrication of electrochemical peptide-based U(VI) sensors. The key innovation of this study is the incorporation of phosphorylated amino acids to enhance the peptide probe’s affinity for U(VI). Additionally, two different probes were designed to address the effects of probe flexibility on sensor response. This study has verified the use of surface-immobilized phosphorylated peptides for detection of U(VI), in addition to guiding future designs of U(VI) capture probes for sensing and remediation applications.Chapter 3 reports the fabrication of an electrochemical DNA (E-DNA) sensor using potential-assisted azide-alkyne “click” chemistry on an alkylphosphonate SAM on an indium tin oxide electrode. The E-DNA sensor was fabricated on a mixed monolayer composed of (5-hydroxypentyl)phosphonic acid and (5-azidopentyl)phosphonic acid. A multi-potential step sequence was used to generate the copper (I) catalyst to facilitate the “click” reaction. Overall, this E-DNA sensor’s behavior is comparable to that fabricated on a gold disk electrode. This combination of sensor substrate and bioconjugation method is versatile and should be compatible with other electrochemical and optoelectrochemical sensors.Chapter 4 investigates the application of both copper-catalyzed alkyne/azide cycloaddition and inverse electron-demand Diels-Alder cycloaddition “click” reactions for site-specific attachment of two redox labels, methylene blue and ferrocene, on a three-component monolayer on a gold electrode. The monolayer consisted of two reactive groups, mercaptoalkylcyclobutene and 8-azidooctanethiol, for attachment of yetrazene-modified and alkyne-modified redox labels. Using the optimized experimental protocol, both redox labels can be immobilized on the monolayer either sequentially or simultaneously. This proof-of-concept study has provided new knowledge on both “click” reactions and their suitability for surface modification.
Subject Area
Chemistry|Design|Physiology
Recommended Citation
Hipp, Kenneth N, "Advancements in Self-Assembled Monolayer-Based Sensing and Surface Modification Technologies" (2021). ETD collection for University of Nebraska-Lincoln. AAI28712833.
https://digitalcommons.unl.edu/dissertations/AAI28712833