A New Diamond Biosensor with Integrated Graphitic Microchannels for Detecting Quantal Exocytic Events from Chromaffin Cells

摘要

The quantal release of bioactive molecules from neurons and neuroendocrine cells is a fundamental mechanism that regulates synaptic transmission and hormone release. In particular, chromaffin cells of the adrenal gland, expressing voltage-gated Ca channels functionally coupled to the secretory apparatus, represent an ideal system to study the exocytotic release of cat-echolamines (adrenaline, noradrenaline) from chromaffin granules, where they are stored at high concentration (1 m) together with ATP, opioids, peptides. Carbon fiber microelectrodes (CFEs) are employed since few decades to detect the exocytotic activity of single excitable cells with amperometric techniques and provide significant information on key mechanisms such as the formation of the fusion pore and the kinetics of single secretory events in real time. These classical carbon-based probes possess high, chemical stability and biocompatibility but can be hardly integrated in a miniaturized multi-electrode device. This limits the possibility of using them in multiple single-cell recordings or even to resolve secretory events within microareas of a single secretory cell. Two technical advances that would be beneficial for investigating the molecular basis of synaptic transmission in neuronal networks and the subcellular arrangement of the secretory apparatus.