Carbon fiber microelectrodes (CFMEs) have been used to detect neurotransmitters and other biomolecules using fast-scan cyclic voltammetry (FSCV) for the past few decades. Here, we measure neuropeptides such as Neuropeptide Y and Oxytocin, a pleiotropic peptide hormones that are important for social behavior. These neuropeptides function as anti-inflammatory agents and serves as antioxidants with protective effects during trauma. Since oxytocin and Neuropeptide Y contain tyrosine, a modified sawhorse waveform was also used to detect these neuropeptides. Additionally, we demonstrate that applying the MSW on CFMEs allows for real time measurements of exogenously applied neuropeptides on rat brain slices. These results may serve as novel assays for neuropeptide detection in a fast, sub-second timescale with possible implications for in vivo measurements and further understanding of the physiological role of these neuropeptides.

We also developed enzyme modified microelectrodes for the measurement of glutamate, which is an important excitatory amino acids and biomarker for epilepsy along with the inhibitory GABA. Since glutamate is not redox active at carbon electrodes, we modified CFMEs with glutamate oxidase enzyme to metabolize glutamate to hydrogen peroxide and alpha-ketoglurarate, which was then oxidized at carbon electrodes. The enzyme coating was optimized by varying the concentration of enzyme, chitosan binder, solvent, and deposition time. The coating was further analyzed electrochemically and imaged with scanning electron microscopy (SEM) for thickness and uniformity of surface coverages. Glutamate oxidation was found to be adsorption controlled to CFMEs and characterized at various scan rates, concentrations, and stability times as well with an approximate 100 nM limit of detection.  Glutamate was co-detected in complex mixtures with several monoamines such as dopamine, serotonin, and others in addition to future in vitro, ex vivo, and in vivo studies.