What looks like a
bed of nails are actually nanowires. Each outgrowing thread
has a diameter of 80
nanometres (billionths of a metre). The green things
climbing on the nanowires are
neurons.
(September 29, 2015) Neurons
thrive and grow in a new type of nanowire material developed by researchers in
Nanophysics and Ophthalmology at Lund University in Sweden. In time, the
results might improve both neural and retinal implants, and reduce the risk of
them losing their effectiveness over time, which is currently a problem.
By implanting electrodes in the brain tissue one can
stimulate or capture signals from different areas of the brain. These types of
brain implants, or neuro-prostheses as they are sometimes called, are used to
treat Parkinson’s disease and other neurological diseases.
They are currently being tested in other areas, such as
depression, severe cases of autism, obsessive-compulsive disorders and
paralysis. Another research track is to determine whether retinal implants are
able to replace light-sensitive cells that die in cases of Retinitis Pigmentosa
and other eye diseases.
However, there are severe drawbacks associated with today’s
implants. One problem is that the body interprets the implants as foreign
objects, resulting in an encapsulation of the electrode, which in turn leads to
loss of signal.
“Our nanowire structure prevents the cells that usually
encapsulate the electrodes – glial cells – from doing so”, says Christelle
Prinz, researcher in Nanophysics at Lund University in Sweden, who developed
this technique together with Maria Thereza Perez, a researcher in
Ophthalmology.
“I was very pleasantly surprised by these results. In
previous in-vitro experiments, the glial cells usually attach strongly to the
electrodes”, she says.
To avoid this, the researchers have developed a small
substrate where regions of super thin nanowires are combined with flat regions.
While neurons grow and extend processes on the nanowires, the glial cells
primarily occupy the flat regions in between.