B1 Intermediate 1855 Folder Collection
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YAEL HANEIN: So I want to describe to you
research activity that is taking place
in my lab over the past several years,
including some extensive collaboration that we
do with several colleagues.
And I want to get started with describing
just a little bit the visual system.
The visual system basically looking
across different creatures, different animals,
is fundamentally the same.
And at the very core, it's the capacity
of the brain to reach out and to look into the environment.
And one of the fascinating things about the visual system
is that it's really adapted to accommodate
the different needs of different creatures.
So humans in particular have very strong needs, one of which
is actually to recognize facial expression.
And clearly, as humans we have developed technology
that goes hand in hand with our visual capacity.
So overall, put together, about 80% of what we perceive
and comprehend, but also remember and plan,
is based on visual information.
So we're really technological creatures, I mean,
and this is probably one of the best places
to highlight this point.
But it's really not just about survival.
It's survival, but also expanding our capacity
in terms of our ability to read, to learn, to plan
the future, which really goes hand in hand
with our technological capacity and our visual capacity.
Now the important thing to realize
is that technology and modern science
actually have some additional link with visual information.
And this is a little bit tricky to comprehend.
So if we look overall at longevity,
we all know that people live longer.
The numbers are quite amazing when we look at them.
And so if you just look at what was the reality just about
100 years ago, people didn't live very long.
So modern medicine had immense capacity
at prolonging life and making all of us live much longer.
So clearly there are some differences
between developing and developed countries.
But generally in the developed world, people live very long.
And this has to do with the ability
to eradicate a lot of diseases that
typically cause early death.
Now how does that relate to vision?
So one of the consequences of living longer
is the fact that certain diseases, as I mentioned,
have disappeared.
But on the other hand, several other diseases
that were unknown before are becoming very prevalent.
And one of them is AMD, or age-related macular
degeneration, which is the situation where
the central part of our macula, or central part
of our visual system, which is the macula, it's
the center of the retina, becomes degenerate.
And that means that when we age, there's
an onset of the disease.
And when we look at the population
of 80-year-olds and above, there's
a staggering number of people that
will suffer from this disease.
So if you go ahead and extrapolate
what would be the situation in 20 years, in 50 years,
the numbers are going to be very high.
So the current estimates is by the year 2050,
among the American population, there
would be over 5 million people suffering from AMD.
Now AMD doesn't mean total blindness,
but what AMD means is that our capacity
to read, to write, to recognize faces
is severely damaged to the point that in many patients
it's damaged completely.
And the consequences are loss of independence, depression,
and a major financial burden on the patients themselves,
but also on additional circles of family and friends.
So by this point you're all spooked.
And this is probably the time to start
talking about the future and the technological solutions.
And so this is where we introduced
the issue of artificial vision.
Now artificial vision sounds like complete science fiction.
But in fact, over the last several decades,
there is a whole range of related technologies
that have been developed and have
been proven to do just what we're
aiming to do in artificial vision.
So cochlear implants are devices that
are implanted in the cochlea in the ear
and have been used already with just over 200,000 people.
And what these devices do, they can take auditory information,
transfer that into electrical stimulation,
and stimulate nerve cells, and basically
address the nerve track in order to stimulate information that
ultimately is conceived as auditory information.
And so this technology has been really the trigger
and the motivation to develop additional technologies
such as the artificial vision.
And so artificial vision are devices
that you see on the right-hand side.
These are actually devices, actual prototypes, two of which
have already passed even regulatory cycles
and are approved for use not for AMD patients,
but for RP patients.
And such devices utilize microfabrication technology
and allows people to see.
Now what does it mean, it allows people to see?
It allows them to have the sensation
of visual information.
So what these pioneering studies have demonstrated
is several very fundamental issues.
First, it has demonstrated the fact
that you can build a device.
You can implant it for a long term.
And you can transfer electrical signals
that are perceived by the brain as visual information.
The second point is that you can also
demonstrate using cochlear implants and these implants,
that the brain plasticity have the capacity to, over time,
to understand better and better this visual information that
is being transferred.
So basically the science fiction part of it
has been taking a little bit out of it in the sense
that we know that these things are technologically possible.
The challenge remains though that the systems that
have been developing over many, many, many years--
this is a long path it takes from the design
to the actual realization of these devices-- they're still
very bulky, very big, require external energy source,
and requires extensive wiring.
And often this wiring has to extend out
of the eyeball, which makes the whole thing pretty messy when
you think about it in terms of surgical procedures.
So that the moon shot thought is really to take all of that
and turn that into a compact device,
basically something that can be inserted neatly into the eye
and placed against the retina.
So this is clearly what you would
like to do when you talk about an artificial retina,
but then the question is how do you go about doing that?
So what you really need is new materials, either new polymers,
new nanotechnology tools, just tools that actually did not
exist when the original artificial retina devices were
beginning to be developed.
So now we do have new materials available.
And what we've been trying to do is really
to go back to the very basics and to try
to imitate the system to the very, very fundamental levels.
So a natural system is relied on photoreceptors.
The photoreceptors are the elements
that are degenerated in AMD.
And what you want is actually the capacity
to be able to elicit electrical information instead
of those elements, instead of these photoreceptors that
are gone.
Now in the natural system, especially in the macula,
there are a lot of these photoreceptors.
There's a very high density of them.
And they operate in a very efficient way.
And so what we're trying to do is
to use carbon nanotube as a scaffold
onto which we want to introduce energy harvesting
elements or photo harvesting elements,
and the combination of these two,
the photo conducting elements on the one hand
and the carbon nanotube as a scaffold on the other hand,
can simultaneously generate the needed electric field,
which is needed in order to stimulate the retina.
Now in terms of actually demonstrating that,
so one approach that we've demonstrated very recently
with colleagues from Bangalore is using conductive polymers.
So you can take newly-developed conducting polymers,
deposit them on the interface of electrodes.
You can take a blind retina, place the blind retina
on the interface, shine light in a very precise way,
and demonstrate that the retina can see.
So this is a blind retina that sees visual information that
are mediated by the special interfaces.
The actual approach, or the major effort in my lab,
is actually to use the carbon nanotubes as a scaffold.
And this is an ongoing work that we've
been doing for the past 10 years in which we've been constantly
demonstrating the great advantage of using carbon
nanotubes for this application.
So carbon nanotubes have several fundamental properties,
which are really ideal for this application.
One is that it's almost like a natural Velcro, which
makes a very strong and intimate contact
with biological systems.
And we've been demonstrating that in vitro, ex vivo,
and in vivo.
So these are absolutely fantastic materials
in binding to the biological system.
The other thing is that they are a fantastic electrochemical
system, and you can use them as electrodes
both for recording and stimulation.
You can really convince yourself that you
obtain absolutely fantastic recording capabilities just
because of their very large, three-dimensional structure.
The other thing, which comes from their entangled nature,
is the fact that you can make films from these surfaces.
You can work out the fabrication process in such a way
that you can integrate that into many different carriers,
into polymeric carriers, which are biocompatible, and can
automatically integrate this whole system
into a standalone device.
So when you take all of these together and use the carbon
nanotube as a scaffold, and now bring
into this party, the quantum rods,
now you have a system that can do both.
It can anchor or bind to the biological system,
but it can also do the energy transfer
of taking photons and converting them
into charge separation, which ultimately stimulate
the retina.
Now there's a lot of science in the science
fiction in the sense that you really
have to work out a lot of details.
There are many, many, many details,
and I have exactly 32 seconds to lay them out.
But you really have to work about how you couple the carbon
nanotubes and the quantum dots.
You really have to make sure that the system
is stable and biocompatible, that the charge transfer
happens in such a way that it doesn't damage the system.
And all of these things have to be, of course, proven.
But once you do that, you actually realize that it works.
And you can demonstrate again, using blind retina, ex vivo,
that using nice, sharply-defined optical pulses,
that you can stimulate the retina
and reconstruct visual information in essentially
a blind system.
So there's a long way to go in order
to fill the full picture of this.
But this is where we're at at the moment
and really looking forward for the future.
So just to conclude, the real challenge
is really at the bottom, not just to extend life,
but really to make sure that this prolonged life is
happy, healthy, and independent.
So thank you very much.
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Solve for X - Yael Hanein - Artificial Solar Retina

1855 Folder Collection
richardwang published on April 18, 2014
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