This black magnetic powder is called magnetite.
That's what the locals of Mayotte (small French island north west of Madagascar) told me.
Some beaches of the island have very dark sand like what we see here.
I was a bad tourist and took some of it home with me (I know that's a bad thing to do).
I extracted the black powder from the rest of the sand with a magnet.
That's how I got my hands on magnetite.
Why was I so interested by the sand that I decided to take a sample home?
Because I know that magnetite is the makeup of a natural detector
that is currently being studied to cure cancer.
If that seems crazy to you, that's because it is.
8 years ago when I first came to Quebec, I worked at a research lab
that sought new methods to cure cancer.
I worked on my own project, and maybe I'll tell you about it someday.
But today we're focusing on Mahmood's project
I am a microbiologist.
That means that I work with tiny organisms
on the micro scale.
His favourite organisms are bacteria called Magnetococcus marinus or MC1 for friends.
At the lab, we would call them Mahmood's babies
because he would take care of them as if they were his children.
If you look at one of his 'babies' on the microscope (scanning electron microscopy), this is what it looks like.
These bacteria measure about 1 micrometer.
1 micrometre is pretty small, it's 0.001mm.
Here they are in a drop of a solution.
Each white dot is a bacteria. It's busy in there!
There's a whole team that works on this project, they're a big team,
and their goal is to use those bacteria to reach a tumor.
In order to make them efficient, they carry cancer-fighting drugs
in little fitted backpacks whose scientific name is liposomes.
The small dots you see here are liposome capsules.
Liposomes are small vesicles of 100-200nm
loaded with drugs.
"Any kind of drugs?"
They can carry any drug, that is up to the doctor ordering the prescription.
'Only' thing that needs to be done now is get the millions of bacteria to move,
each one loaded with 70 drug backpacks and directly targeting the tumor
inside the trickiest part, a zone called hypoxic.
A hypoxic region is one where oxygen is rare,
and that's where cancer cells develop a lot faster.
Finding a way to send medicine only where the tumor is
is the Holy Grail of cancer research.
The drugs currently in use are efficient against tumors
but the issue is that they also attack healthy tissues...
What then? How can researchers, and more importantly bacteria, focus in on the tumor?
MC1 is the Leeloo of bacteria, it is perfect.
It has 2 natural sensors that it uses to find its way in the ocean,
and that's what we use to move it towards tumors.
The first sensor allows the bacteria to find a concentration of oxygen in the water.
That's called aerotaxis.
The second sensor allows it to follow the direction of Earth's magnetic field.
That's called magnetotaxis.
The bacteria are said to be magnetotactic.
What's crazy is that you can actually see this sensor.
This is the same bacteria observed under an electronic microscope,
but it was cut in half.
It's inside of the bacteria that you can see this little pearl necklace.
They are magnetite crystals…
the same stuff I had found on the beach.
Except that my grains are so big that we can see them with the naked eye.
Those of the MC1 are only a few nm large and they're called magnetosomes.
You'll notice that they hang out in lines. There's a reason why they do that.
The chain of magnetosomes works like a magnet.
A magnet. That's the magnetic pearls' main function,
they act as a compass.
The magnetosome chain aligns itself to the magnetic field of the Earth,
and that's the direction that the bacteria will follow
towards the bottom of the ocean.
Okay so in my head, I pictured the lines of Earth's magnetic field as
parallel to its circumference, except at the poles.
So I didn't get how the bacteria would go deep into the sea if they followed those lines.
But actually, in the Northern hemisphere, the lines of the field are diagonal
and they end up leading the bacteria to the bottom of the ocean.
This is a group of traveling bacteria. They aren't following the magnetic
field of Earth but a magnet that Mahmood is working with.
His magnetic field is so much stronger than that of Earth that the bacteria follow that one instead!
His control over the bacteria is so strong that Mahmood was able
to use them, his 'babies', to build a pyramid using a mere magnet.
What you need to understand is that magnetic fields only give the bacteria a direction.
What makes them move is their own flagellum.
Those give them massive speed.
200 microns per second.
They are very fast.
Imagine a swimmer that can swim 200x their height per second
But in order to go from building pyramids to steering bacteria in every direction
inside of a living body to target a tumor,
there are some technological steps.
into which the researchers can decide where to focus the swarm of bacteria.
With that machine, researchers will create a 3D magnetic field
to move the bacteria from the injection site to the tumor.
But even once arrived at the tumor, the job isn't done yet.
From that point on, the magnetic field is useless. They need another mechanism:
the bacteria’s aerotaxis.
That's where the concentration of oxygen is very low…
That’s what bacteria love!
and another with oxygen (outer circle).
That’s what bacteria love!
in an area in between: the low in oxygen, hypoxic zone.
At the edge of the tumor, there is too much oxygen for them
so they naturally go towards the proliferation zone of the tumor.
At that point, they've already been swimming in a 37C environment for a few minutes.
That is way too hot for them, so they will die quickly
and the liposomes will dissolve and release the drug at the exact right place.
At that point, they've already been swimming in a 37C environment for a few minutes.
That is way too hot for them, so they will die quickly
I love this kind of research that combines biology, physics and technology
for the benefit of health. But it is just research.
so it is much too soon to try and extrapolate the results to us.
I don't want to give you false hope.
But there is progress. And perhaps in a few years, some cancers will be treated
with small bacteria gone hiking with their backpacks full of drugs,
moved by their magnetic compass and attracted by the hypoxia of the tumor.
In this video, I didn't get into what cancer is so if you'd like to know more,
But there is progress. And perhaps in a few years, some cancers will be treated
with small bacteria gone hiking with their backpacks full of drugs,
moved by their magnetic compass and attracted by the hypoxia of the tumor.
don't forget to share, like and comment.
Speaking of more videos,
I have a whole bunch of magnetite, more than what you saw here,
so if you have ideas for experiments I could do with it,
don't forget to share, like and comment.
And you can subscribe and click on the bell to get notifications for the next videos.
Speaking of more videos,
I have a whole bunch of magnetite, more than what you saw here,
so if you have ideas for experiments I could do with it,
please leave a comment down below!
Bye!
I also want to thank Mahmood Mohammadi
from the nanorobotics lab of Polytechique Montreal
for explaining his research to me.