(315g) New Electrochemical Sensing Platforms to Detect Ultra-Low Concentrations of Toxic Metals

Exposure to toxic metal ions is rising due to increased urbanization and industrialization; thus, humans are at a greater risk of getting metal toxicity due to exponent bioaccumulation along the food chains. Although the detrimental heal hazards associated with metal toxicity are well documented, there's a lack of proper analytical tools that can provide reliable qualitative and quantitative information about toxic metal ions due to several reasons, such as the complexity of metal chemistry and the limitations of fabrication and analysis protocols of sensors. Therefore, most existing methods rely on the measurements taken on postmortem tissues or urine and blood samples collected from the patients, thus, missing real-time information about the metal speciation and interactions. Moreover, a tool capable of early detection would be ideal for starting early therapeutics, thus preventing further accumulation and minimizing damage to vital body organs. In this vein, we develop different types of novel electrochemical sensors that are redox-based and non-redox based to detect ultra-low concentrations of toxic metals in complicated, aqueous buffers that mimic body fluids or in artificial blood and urine samples. Our nanoelectrodes based on ion transfer across two immiscible electrolyte solutions (ITIES), can detect Cd(II) ions with great sensitivity and excellent stability in complex matrices, including artificial urine and blood samples. We also engineered a novel, surface-modified carbon-fiber microelectrode (CFM) by electrodepositing dopamine onto the electrode surface to detect ultra-low concentrations of toxic metal ions in real-time using fast scan cyclic voltammetry (FSCV). Our surface-modified CFMs significantly improved the limit of detection and sensitivity of Cu(II) detection compared to bare CFMs. Moreover, we fabricated a double-bore CFM with two sensing components that can simultaneously measure two neurotransmitters and toxic metals via FSCV without altering the detection window of each analyte. To the best of our knowledge, this is the first electrochemical sensor to detect multiple analytes at ultra-fast scan rates. Our preliminary data obtained with these sensors showcases a great possibility of developing these sensors for future in vivo applications.