  The quantal release of catecholamines from neuroendocrine cells is a key
mechanism which has been investigated with a broad range of materials and
devices, among which carbon-based materials such as carbon fibers, diamond-like
carbon, carbon nanotubes and nanocrystalline diamond. In the present work we
demonstrate that a MeV-ion-microbeam lithographic technique can be successfully
employed for the fabrication of an all-carbon miniaturized cellular bio-sensor
based on graphitic micro-channels embedded in a single-crystal diamond matrix.
The device was functionally characterized for the in vitro recording of quantal
exocytic events from single chromaffin cells, with high sensitivity and
signal-to-noise ratio, opening promising perspectives for the realization of
monolithic all-carbon cellular biosensors.
