Micro- and nano-electrodes for neurotransmitter monitoring

Chemical transmission between neurosecretory cells is a central biological phenomenon. Detecting neurotransmitter molecules released in the brain or in cell cultures is key to understanding how, when, and where chemical transmission occurs. Electrochemical techniques provide a unique quantitative approach to this field of research. Micro- and nano-electrodes can be engineered to be implanted in the living brain for interstitial fluid analysis, or placed close to, or even inside, isolated cells to detect exocytosis events and vesicles. Carbon fiber microelectrodes provide a common basis for detecting not only dopamine but also a wide variety of neurotransmitters ranging from biogenic amines, purines, and amino acids to free radicals and peptides. To achieve specific and sensitive in situ neurotransmitter detection, carbon fiber microelectrodes can be chemically modified with nanomaterials, enzymes, or aptamers or etched to reach nanoscale dimensions for intracellular analysis. Such micro- and nano-electrodes are an essential tool for analyzing living cells and tissues.