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Design, characterization, and interrogation of surface-based electrochemical biosensors
Many modern technologies rely on the the use of sensors, or devices that translate subtle differences in the chemical or biological composition of sample into a measurable response. The most widely recognizable sensor, the glucose meter, serves as just one example of the impact that a reliable diagnostic device can have on the quality of life of people affected by life-threatening health conditions. As exemplified with the glucose meter, the capacity of analytical devices to perform a given task may be greatly enhanced by incorporating biointerfaces, or surfaces populated with biological recognition molecules, into the sensor design. Sensors that implement biological probes to engineer ''smart'' surfaces for target recognition are commonly referred to as biosensors. This dissertation describes the design and development of electrochemical biosensors that rely on the ability of biological recognition probes to selectively bind to their respective targets with high affinity. Biological probe molecules are constructed for compatibility with electrochemical interrogation by conjugating a thiolated linker at the probe terminus that facilitates tethering to a gold electrode. At the other end, the probe is modified with an electrochemical reporter molecule that can be monitored using a variety of electrochemical methods. Binding of the target to a surface-anchored probe leads to changes in probe flexibility or conformation in proportion to target concentration. Consequently, the presence of the target in a sample has a strong influence on the electrochemical signal arising from the reporter molecule. The development of two electrochemical biosensors that rely on the recognition of two distinct probe-target couples, is described herein. The first system utilizes a short antigenic peptide probe to capture its target antibody while the second system relies on the binding of a structure-switching DNA aptamer to a small molecule target. Sensor figures of merit for both systems are determined using cyclic and alternating current voltammetry. The structural and functional properties of aptamer-modified biointerfaces are additionally investigated using combinatorial spectroscopic ellipsometry and quartz crystal microbalance.
Gerasimov, Jennifer Y, "Design, characterization, and interrogation of surface-based electrochemical biosensors" (2013). ETD collection for University of Nebraska - Lincoln. AAI3559486.