Translator: Nika Kotnik Reviewer: Matej Divjak
Good evening.
What do sugar, orange juice,
potato chips, cancer and romanesco broccoli have in common?
Electroporation.
Electroporation is a phenomenon that occurs on the level of a membrane
when the cell is exposed to an electric field.
Molecules, which cannot otherwise pass the membrane, can then enter
through the membrane because of these changes due to electroporation.
A cell can survive electroporation,
but such damage can occur that the cell dies.
In the first case it is called reversible,
and in the second, irreversible electroporation.
At the Faculty of Electrical Engineering, University of Ljubljana,
where we have been dealing with electroporation for more than 20 years,
and in cooperation with the Institute of Oncology in Ljubljana,
we have primarily focused on the use of electroporation in medicine.
Then, some five years ago,
I gazed for a moment at a "parallel world",
in which electroporation was used in processing food.
They even used a different name, PEF treatment, pulsed electric field,
which means that there were two parallel worlds,
so I began to establish wormhole between these two worlds,
since I'm sure that we can learn from each other.
Not just that, I see huge potential for electroporation in other fields, too,
such as biotechnology, energy, and the environment.
Three years ago, I proposed a project
in which more than 500 scientists from 40 countries
have been included so far
and in which we deal with electroporation in all the aforementioned fields.
Cancer.
An illness that we meet too often, directly or at least indirectly,
is still usually tackled with surgery, radiotherapy, and chemotherapy.
And precisely with chemotherapy,
electroporation can essentially increase
the effect of some chemotherapeutics; even 1,000 to 10,000 times.
If a suitable chemotherapeutic is selected, and the membrane presents
an impermeable barrier for a chemotherapeutic,
we cause electroporation with some 100 μs pulses,
thus increasing the permeability of the membrane
and allowing entry of molecules of the chemotherapeutic into the cell.
The effectiveness of the chemotherapeutic is thus essentially improved.
It looks like this,
on the left lower side you can see a tumor on the head,
electrochemotherapy of 8x100 μs pulses was applied once, a single session;
after a couple of days a scab appeared,
the surrounding skin is unaffected
and, after 10 weeks, the tumor has gone.
In about 70% of cases, a single therapy is enough to make the tumor disappear.
The electrochemotherapy can of course be repeated.
Since 2006,
when equipment for clinical electroporation came on the market
as a result of two parallel European projects in which we participated,
it has spread to 150 hospitals
throughout Europe.
And the number of patients who are treated with electrochemotherapy
is increasing year by year.
In terms of electrochemotherapy and treatment of skin metastases,
that is cutaneous and subcutaneous tumors,
the procedure is relatively simple.
After we have injected the chemotherapeutic,
we choose a suitable electrode,
place it at the site at which we can see the tumor, deliver an electric pulse
and then wait for the tumor to disappear.
There is no reason, of course, why deeper lying tumors
should not be treated in the same way.
We must choose an electrode that we can "insert" into the body, of course.
There are two problems:
the first is that we cannot see the tumor with the naked eye
so we use medical imaging,
X-ray, magnetic resonance imaging;
and in positioning the electrode we use X-ray or ultrasound,
so that we know where we are placing the electrode.
However, once we have inserted the electrode into the body,
we cannot simply move it, so we must of course know in advance precisely
from which side we will insert the electrode, how we will arrange it
in relation to the tumor and what voltage we will deliver.
For that we use a treatment plan.
Our group started in 2009 - at that time the first in the world
and still practically the only one - to prepare a treatment plan
for electrochemotherapy for each patient individually who is treated in Slovenia.
We thus currently support four clinical studies taking place in Slovenia
and we are in process of agreeing to support clinical studies outside Slovenia.
I will show you one example:
you can see the metastasis
of the cancer of the large intestine
to the liver, wedged between the main liver blood vessels
and so it could not be removed surgically,
nor was it possible to use other ablation methods,
that is to say, other methods of destroying these tumor cells.
The surgeons therefore decided that they would apply electrochemotherapy.
We prepared a treatment plan of electrochemotherapy
and in December, it will be five years since it was applied
at the Oncology Institute in Ljubljana.
After a few months, on the basis of pictures and results,
the surgeons decided to operate again and when they went to look,
they saw that there were in fact no tumor cells any more.
The tumor had gone.
Histological tests also showed that the tumor had gone.
The patient has since been without signs of illness for five years.
A cell, if you remember, is surrounded by a membrane,
and inside a heap of things whose names you have forgotten.
For me, an electrician, that is much too complicated a picture.
Let's simplify it a bit, though.
(Laughter)
With what I now know.
When I apply an electric field, these pluses and minuses begin to travel.
Those that are outside are not shown at all. They have no problem traveling.
Those that are surrounded by the membrane, though,
come up against the membrane and cannot cross it. Why?
Why?
When we put salt in water, sodium chloride or potassium chloride,
the potassium and chlorine each go their own way and are surrounded by water,
just wandering about a bit, in this case the potassium and chlorine.
When we set up an electrical field
plus ions start to go towards the minus and the minus towards the plus
and we call this an electric current.
Our body is actually an electrolyte, that is to say salt dissolved in water,
as well as some membranes.
When, under the influence of the electrical field, these membranes
prevent the ions from traveling,
they start to accumulate at the membrane,
with a surplus of plus on one side and a surplus of minus on the other.
The membrane is extremely thin,
a few nm, 4 - 5 in this case.
The ions dissolved in the water cannot pass through the membrane
because the membrane is made to resist water
and now because a very high electrical field across the membrane,
the water starts to orientate into this field and a pore is created,
that allows ions to move from one side to the other.
In this way, to transpose to the present, with the flow of electroporation
other molecules dissolved in water can also now pass through the membrane.
I mentioned at the start that electroporation can also be irreversible,
which means that, at the end, the cells die.
Orange juice is good if it is freshly squeezed.
Better than what we buy in the shops.
On the upper shelf you can see freshly squeezed juice;
with that on the extreme left we do nothing, merely close it and store it.
After a few days, and certainly after a few weeks,
even if it is in the refrigerator, it becomes strange;
some floats to the top, in the middle is something transparent
and on the bottom is some sediment, certainly not juice you want to drink.
On the far right side on the upper shelf is thermally treated juice,
pasteurized juice, like you usually buy in a shop.
Such juice, treated at 90°C
doesn't spoil for a long time, even several weeks.
And in between on the upper shelf, you can see the juice
processed with various parameters of electroporation
but the temperature is never raised above 50°C.
The juice keeps as long as the thermally treated juice, it does not spoil,
while we have not decreased the anti-oxidants
and destroyed the vitamins, because we have not heated the juice.
You mainly buy heat pasteurized juice
but it is already possible to get pasteurized juice by electroporation.
Sugar.
One of the ways of obtaining sugar
is by pressing the sugar juice from sugar beet.
If you press sugar beet, juice does come out
but most of the sugar and water
is captured by the membranes in cells.
If we electroporate it before pressing it, we can squeeze more juice from it.
In the established procedure,
the beet is heated to 72°C,
increasing the permeability of the cell membrane, raising the temperature
to the point at which the membrane is damaged and, when the beet is pressed,
exactly as much juice is extracted as you get by prior electroporation.
However, if we use electroporation instead of heating,
colleagues from Germany have done the calculations and shown,
we use 100 times less energy.
Translating the savings into release of greenhouses gases, it means
that if in Germany electroporation was introduced
in all sugar factories,
the effect would be the same as taking 200,000 cars off German roads.
Now French fries.
At home we peel a potato, cut it and submerge it in oil.
If we're completely honest, practically nobody does that at home any longer.
We normally go to one of those fast food places or to a cafeteria
and there treat ourselves to chips, and a little mayonnaise to go with them.
In contrast to animal cells, plant cells
have cell walls as well as membranes.
Pressure is higher inside the plant cell than outside-turgor pressure.
Turgor is responsible
for the plant's rigidity and firmness of texture.
If we now electroporate the membrane, a little water runs out
and we can now make a knot out of the raw potato.
Try to do that without electroporation.
Not just that: if electroporated potatoes
are compared to unelectroporated potatoes when they are cut in a factory
in which production is fifty tons an hour and more,
we see the edge of the left hand potato, which was electroporated,
is much smoother,
the right hand potato has some cracks
and is actually broken during processing,
so that we get these small, broken chips that nobody likes.
We all want the nice long ones.
Oil enters into the potato through these cracks when we fry.
It appears that 10 - 20% less oil is used
with electroporation treated potatoes.
This of course means
that a huge quantity of oil is saved.
It also of course means that the potato is less greasy,
so also less good.
But we can replace that with mayonnaise, remember?
(Laughter)
Cooking, if you didn't know, is why our brains are as they are,
the reason why we can ask
who I am, why I am,
and also why we go to the TEDx events.
We cook food for two reasons.
First, to destroy micro-organisms, those that could spoil the food,
and perhaps also pathogens that could harm our health.
Maybe even more important,
if we look at what food actually is,
it is now a simplified cell again - food is actually sugars,
fats and proteins, which are for the most part located within cells.
The second reason for cooking food is that these molecules,
these sugars, must enter the blood and our cells,
which can then use them for food.
Cooking therefore increases the availability of these molecules
for our enzymes, for our digestive system.
We normally do this by heating.
Well, if you think that you have the most modern cooker
just because you have an induction one at home, you're wrong.
The most modern cooker is a cooker that uses electroporation.
I'll now show you, as an example,
how food cooked with electroporation looks.
A premier, the first in Slovenia.
We need less than a second to cook meat with electroporation.
We must still heat it a little and the food must obtain a little color
so we use another two to three minutes for meat
and perhaps a minute or two longer for vegetables.
If you want to see such food for real or to taste food prepared in such a way,
then you must come to the first Congress of Electroporation next year,
which will be held in Portorož, Slovenia.
Thank you very much.
(Applause)