Carbon fiber microelectrodes (CFEs) are useful when
combined with electrochemical techniques for measuring changes in
neurotransmitter concentrations. We addressed conflicting details regarding the
use of CFEs. Experimental groups consisted of CFEs at different ages (1 week, 1
month, or 2 months), cleaned in solvents (isopropanol or xylene), and exposed
to in vitro use (flow cell
calibrations) or in vivo use (in
brain tissue). In order to determine if any of these factors affect CFE
sensitivity, the present study utilized fixed potential amperometry and a flow
injection system to calibrate CFEs for the measurement of dopamine. The
sensitivity index (nA/μM per 100 μm of exposed carbon fiber) was not affected
by the age of CFEs or pre-cleaning with xylene or isopropanol. CFE sensitivity
of the in vitro exposure group also
did not differ from untreated CFEs, indicating the calibration process did not
alter sensitivity. However, in vivo use in brain tissue did reduce sensitivity. This effect was negated and
sensitivity restored by cleaning CFEs in isopropanol or xylene following in vivo brain recordings. Given that
variations in CFE sensitivity can skew results, our findings can help
standardize CFE use and explain discrepancies between researchers.
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