By richard wilson 10th
March 2016
Researchers in the UK and Italy
believe a breakthrough in treatment of motor disorders, such as epilepsy or
Parkinson’s disease, may be possible and with electronic neuron interface
devices fabricated from pure graphene, writes Richard Wilson.
Treatment of patients with motor
disorders such as Parkinson’s disease could one day benefit from graphene, the
highly conductive material which is expected to have electronics applications
ranging from solar cells to semiconductors.
Researchers from the University
of Trieste in Italy and the University of Cambridge’s Graphene Centre say it is
possible to use graphene to make electrodes that can be implanted in the brain,
which could potentially be used to restore sensory functions for amputee or
paralysed patients, or for individuals with motor disorders such as Parkinson’s
disease.
“We are just at the tip of the
iceberg when it comes to the potential of graphene and related materials in
bio-applications and medicine,” says Andrea Ferrari, director of the Cambridge
Graphene Centre.
Graphene is a promising material
for fabricating biomedical devices because of its high conductivity,
flexibility, biocompatibility and stability within the body.
The important discovery the
researchers in Cambridge have made is to demonstrate how graphene, which is a
two-dimensional form of carbon, can be interfaced with neurons, or nerve cells,
while maintaining the integrity of these vital cells.
The interaction between graphene
and neurons, which has been investigated already, is very problematic because
the signal to noise ratio from this interface can be very low.
What the Cambridge team has
achieved is to develop methods of working with untreated graphene, which
retains the material’s electrical conductivity, making it a significantly
better electrode.
“For the first time we interfaced
graphene to neurons directly,” said Professor Laura Ballerini of the University
of Trieste in Italy. “We then tested the ability of neurons to generate
electrical signals known to represent brain activities, and found that the
neurons retained their neuronal signalling properties unaltered. This is the
first functional study of neuronal synaptic activity using uncoated graphene
based materials.”
According to Ferrari, the Cambridge
Graphene Centre has been able to produce large quantities of
pristine graphene material in solution, which has made it possible to prove the
compatibility of the process with neuro-interfaces.
When it comes to applying the
graphene to neuron signalling, the potential applications could be wide-ranging
and significant in the area of brain science.
For example, surgeons believe
that by creating an electronic interface between the brain and external systems
it is possible to harness and control some of the brain’s functions.
“For instance, by measuring the
brain's electrical impulses, sensory functions can be recovered. This can be
used to control robotic arms for amputee patients or any number of basic
processes for paralysed patients – from speech to movement of objects in the
world around them,” said the researchers.
This also means that by
interfering with these electrical impulses, motor disorders, such as epilepsy
or Parkinson’s disease, could start to be controlled.
This is possible because the
electrodes can be embedded deep within the brain where they connect directly to
neurons and transmit their electrical signals away from the body, allowing
their meaning to be decoded.
For this to be achieved the
electrodes need to be able to detect very small electrical signals, they must
also be made from a material which is stable in the body and none invasive to
the human tissue they measure.
Instead of traditional electrode
materials such as tungsten or silicon, the Cambridge group used graphene which
is both highly sensitive to electrical signals, due to its conductivity and it
is stable within the body.
First experiments have been
carried out in rat brain cell cultures and the researchers found that untreated
graphene electrodes interfaced well with neurons.
By studying the neurons with
electron microscopy and immunofluorescence the researchers found that they
remained healthy, transmitting normal electric impulses and, importantly, none
of the adverse reactions which lead to the damaging scar tissue were seen.
According to the researchers,
“this is the first step towards using pristine graphene-based materials as an
electrode for a neuro-interface.”
Professor Maurizio Prato from the
University of Trieste says “the development and translation in neurology of
graphene-based high-performance bio-devices requires the exploration of the
interactions between graphene nano- and micro-sheets with the sophisticated
signalling machinery of nerve cells. Our work is only a first step in that
direction.”
The research, which was published
in the journal ACS Nano, was funded by the Graphene Flagship, a European
initiative which promotes a collaborative approach to research with an aim of
helping to translate graphene out of the academic laboratory, through local
industry and into society.
http://www.electronicsweekly.com/news/pwm-motor-control-has-precision-for-surgical-drills-2016-03/
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