So I'm here today surrounded by all these fruits and vegetables,
because these are the subjects of my experiments.
Now, bear with me for just a second,
but about a decade ago
my team started to rethink how we make materials
for reconstructing damaged or diseased human tissues,
and we made the totally unexpected discovery
that plants could be used for this purpose.
In fact, we invented a way to take these plants
and strip them of all their DNA and their cells,
leaving behind natural fibers.
And these fibers could then be used as a scaffold
for reconstructing living tissue.
Now I know this is a little weird,
but in our very first proof-of-concept experiment,
we took an apple,
carved it into the shape of a human ear,
and then we took that ear-shaped scaffold,
sterilized it, processed it
and coaxed human cells to grow inside of it.
We then took the next step and implanted it,
and we were able to demonstrate
that the scaffolds stimulated the formation of blood vessels,
allowing the heart to keep them alive.
So not too long after these discoveries were taking place,
I was at home cooking asparagus for dinner,
and after cutting the ends off,
I was noticing that the stalks were full of these microchanneled vascular bundles.
And it really reminded me
of a whole body of bioengineering effort aimed at treating spinal cord injury.
Up to half a million people per year suffer from this type of injury,
and the symptoms can range from pain and numbness
to devastating traumas
that lead to a complete loss of motor function and independence.
And in these forms of paralysis,
there's no accepted treatment strategy,
but one possible solution
might be the use of a scaffold that has microchannels
which may guide regenerating neurons.
So, could we use the asparagus and its vascular bundles
to repair a spinal cord?
This is a really dumb idea.
First of all, humans aren't plants.
Our cells have not evolved to grow on plant polymers,
and plant tissues have no business being found in your spinal cord.
And secondly,
ideally these types of scaffolds should disappear over time,
leaving behind natural, healthy tissue.
But plant-based scaffolds don't do that,
because we lack the enzymes to break them down.
Funnily enough,
these properties were exactly why we were having so much success.
Over the course of many experiments,
we were able to demonstrate
that the inertness of plant tissue is exactly why it's so biocompatible.
In a way, the body almost doesn't even see it,
but regenerating cells benefit from its shape and stability.
Now this is all well and good,
but I constantly felt this weight of doubt
when it came to thinking about spinal cords.
So many scientists were using materials from traditional sources,
like synthetic polymers and animal products --
even human cadavers.
I felt like a complete outsider
with no real right to work on such a hard problem.
But because of this doubt,
I surrounded myself with neurosurgeons and clinicians,
biochemists and bioengineers,
and we started to plan experiments.
The basic idea is that we would take an animal,
anesthetize it,
expose its spinal cord
and sever it in the thoracic region,
rendering the animal a paraplegic.
We would then implant an asparagus scaffold
between the severed ends of the spinal cord
to act as a bridge.
Now this is crucially important.
We're only using asparagus.
We're not adding stem cells or electrical stimulation
or exoskeletons
or physical therapy
or pharmaceuticals.
We're simply investigating
if the microchannels in the scaffold alone
are enough to guide the regeneration of neurons.
And here are the main results.
In this video, you can see an animal about eight weeks after being paralyzed.
You can see she can't move her back legs,
and she can't lift herself up.
Now I know how difficult this video is to watch.
My team struggled every day with these types of experiments,
and we constantly asked ourselves why we were doing this ...
until we started to observe something extraordinary.
This is an animal that received an implant.
Now she's not walking perfectly,
but she's moving those back legs
and she's even starting to lift herself up.
And on a treadmill,
you can see those legs moving in a coordinated fashion.
These are crucial signs of recovery.
Now we still have a lot of work to do,
and there are a lot of questions to answer,
but this is the first time anyone has shown
that plant tissues can be used to repair such a complex injury.
Even so, we've been sitting on this data for over five years.
Doubt drove us to repeat these experiments again and again,
to the point of almost bankrupting my lab.
But I kept pushing,
because I knew these results could be the start of something extraordinary.
And what's just as exciting
is that my company is now translating these discoveries into the clinic --
into the real world.
This technology has just been designated a breakthrough medical device by the FDA.
And this designation means
that right now we're in the midst of planning human clinical trials
set to begin in about two years.
So I'd like to show you a prototype
of one of our state-of-the-art spinal cord implants.
It's still made from asparagus
and contains all of those microchannels.
And you can see that it moves and bends
and has the same feel as human tissue.
And you know,
I think the real innovation is that we're now able to design
or program the architecture and structure of plant tissues in such a way
that they could direct cell growth to address an unmet medical need.
As scientists,
we spend our lives living on a knife's edge.
On the one hand,
it's our job to fundamentally broaden the horizons
of human knowledge,
but at the same time, we're trained to doubt --
to doubt our data, to doubt our experiments,
to doubt our own conclusions.
We spend our lives crushed under the weight
of constant, unrelenting, never-ending anxiety, uncertainty and self-doubt.
And this is something I really struggle with.
But I think almost every scientist can tell you
about the time they ignored those doubts
and did the experiment that would never work.
And the thing is, every now and then,
one of those experiments works out.
The challenge we face is that while doubt can be destructive
to your mental health,
it's also the reason why scientific rigor is such a potent tool for discovery.
It forces us to ask the difficult questions
and repeat experiments.
Nothing about that is easy.
And often it becomes our responsibility
to bear the burden of the hard and sometimes heart-wrenching experiment.
This ultimately leads to the creation of new knowledge,
and in some really rare cases,
the type of innovation that just might change a person's life.
Thank you.