Electrochemical Analysis of Silver-CNT Electrode Based Biosensors
Abstract
There have been continuous demands to develop better biosensors, which identify the presence of a particular biological strain within a fluid sample, in an inexpensive, readily available and reliable manner. Our research aims to analyze the degradation mechanism in silver-CNT electrode-based biosensors, using electrochemical analysis methods. These sensors were developed with and without a conducting polymer layer, polyethyleneimine (PEI), across the CNT surface, as the PEI can improve the precision of such devices. However, the sensors are suffering from continuous change in resistance, therefore, we executed an electrochemical analysis using electrochemical impedance spectroscopy (EIS). The resistance and capacitance of a fluid bio-sample was measured and compared to resistance and capacitance of the fluid solvent. By repeated EIS experiments on the same sensors over time, we observed that the sensors experience their most dramatic decay within the first 8 hours of production and completely settled after 2 weeks. This might be explained by the fact that CNTs are known to experience oxidation, which can change their material properties. To identify if this is the cause of the decay, we took sensors immediately after manufacturing, both with and without a PEI layer and placed them inside a vacuum chamber for a 7-hour period. We observed an initial increase in resistance from both sensors immediately after removing them, after which they resumed their previously observed rate of decay; indicating that oxygen does contribute to the degradation.
About the Presenter
Jonathan Hammond
I am a first year WSUV graduate student working towards my master’s degree in mechanical engineering. I work in the electrochemical engineering lab, where my research focuses on computer-based modeling of electrochemical systems, such as biosensor and battery technologies.