| Current detection methods for the marine toxin saxitoxin (STX) are bulky, expensive, or require loss of animal life. This dissertation describes progress toward development of a sensitive, portable electrochemical sensor for STX detection. The sensor design employs saxiphilin c-lobe, a STX-binding protein, immobilized in a microchannel for capture of STX. Upon binding of STX, an electroactive competitor---ferrocene-conjugated STX (FcSTX)---will be displaced from saxiphilin c-lobe and detected at an array of individually-addressable microelectrodes incorporated into the microchannel device, with signal amplified by redox cycling. Described herein are: expression, purification, and characterization of saxiphilin c-lobe and analysis of its interaction with STX by surface plasmon resonance fabrication and characterization of the microchannel with microelectrode array synthesis and electrochemical characterization of FcSTX and demonstration of its activity toward saxiphilin c-lobe and necessary improvements to the device to make it suitable for electrochemical detection of STX using the competitive binding assay. |
