MIT
Technology Review: A team of researchers at Duke University
in North Carolina has created a probe that is small enough to
enter a single neuron, and sensitive enough to measure
variations in the cell's electrical activity. The 1-mm-long and
5- to 10-μm-diameter probes are made of tangled carbon
nanotubes attached to the end of a tungsten wire and covered
with a thin insulating film. The researchers used a beam of
focused ions to remove the insulation from the tip and shave it
to a very fine point. The design will allow for even longer and
thinner probes in the near future. The researchers tested the
probes on dissected slices of still-living mouse brain tissue
and on anesthetized mice. Although they were able to detect
signals in the slices, they could not read from the live mice.
The researchers attribute that failure to the size of the
current probes, which may still be too large to penetrate
nonneural tissue. The ability to read individual neuron cell
activity will help researchers better understand how signals
are passed between cells.
