81 research outputs found
A new diamond biosensor with integrated graphitic microchannels for detecting quantal exocytic events from chromaffin cells
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
Fabrication of conductive micro electrodes in diamond bulk using pulsed Bessel beams
High-quality, in-bulk conductive graphitic microelectrodes are fabricated perpendicular to the surface of a 500
μm thick monocrystalline CVD diamond sample using pulsed Bessel beams. With a 12o cone angle beam, different
pulse parameters are explored to optimize the graphitic wires which are written without sample translation. The
quality of the electrodes and their electrical and structural properties have been analysed through currentvoltage
characterization and micro-Raman spectroscopy. We have found that higher pulse duration favours
better conductivity while pulse energy has an optimum value for the same. This trend is confirmed by the
presence and the different amounts of graphitic-like sp2 bonded carbon revealed by the micro-Raman spectra in
different configurations. Using suitable writing parameters, we are able to create electrodes with the resistivity of
0.04 Ω cm, which, to the best of our knowledge, is one of the lowest values ever reported in literature in the case
of graphitic-like wires fabricated through laser micromachining
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