Hello, and welcome to the Physics World weekly
podcast.
I'm Hamish Johnston.
Coming up in this episode, I'm in conversation
with an expert on 4 d printing,
who explains how the technology can be used
in applications as diverse as medicine and flat
pack furniture.
And he also explains how he's used A3D
printed material
to create
self healing asphalt.
But first, physics world's margaret Harris is in
conversation with a neuroscientist
and physicist
who discovered by accident that diamond dust is
a highly effective
contrast agent for magnetic
resonance
imaging.
I'm speaking with Il La
At the Math Planck Institute for intelligent systems.
Her background is in physics and also in
neuroscience research. Hello, Is Elena.
Hi. Hello Margaret.
So
why don't you just begin by telling me
a little bit about your general research program
at the Max planck? What are you trying
to do in your research?
So I can just save and I first
came here for an interview. I decided out
of the blow to apply for the Max
planck institute, there was actually very interesting
advertisement.
For somebody who is who has background in
the Mri magnetic resonance
imaging to do some robotic imaging. And I
will super interesting and curious. What is it
about, and I applied, and they invited me
for an interview.
And then I kinda got into this world
of,
micro robots, and I have to see it
that my boss met city.
Is actually super super shameless us in this
area.
And he does all these robotics that I
didn't know about, and I think lot of
people that come to visit our lab are
like super stoked when they learn about the
research. So in the nutshell, what we are
trying to do here is we are trying
to lose robotics, to deliver the drugs to
the body. So
instead of, let's say, take the drugs is
usually through mouth or
I,
the drugs will end up everywhere. So we
are trying to actually have a focus delivery,
which will bring those drugs all in and
their are where they're needed. So for example,
if you have to treat the cancer when
we have to kill all the cells in
your body in order to treat the cancer,
but you just delivered the drug that will
actually go the racket to the cancer, and
then you also have the mechanism to release
this drug. So it's called on demand
driver release, and we can also navigate these
robots to the place
where it's needed it.
So super
interesting.
So I think your your work is also
on... You've been doing some work about contrast
agents tell me a little bit about what
contrast agents, you know, for listeners who aren't
familiar with the concept to it. And what
are they designed to do?
So the contrast agent, basically in India mri,
they, I would say the were
revolutionized the Mri because,
for example, for the brain imaging,
brain is
in oregon, we are the
agent or more foreign an object can penetrate.
But now you have discussed first agent then
can go where the blood barrier is broken,
which is case and tumors
and they light up. And if you done
at this
agent, you might miss this like,
small, guess, tissue variances in signal that are
caused by tumors, but when we have additional
contrast agent,
basically, the signal and gets so much higher
in increase that you are very, it's very
difficult to my so it helps the doctors
decide how bad your tumor is
and,
yeah. And to actually visualize the tumor much
better. Special in the case in they're really
small. It helps basically
diagnose.
So it's for diagnostic
or
Okay. That sounds like a pretty important substance.
So so what what chemicals or what substances
are generally used for contrast agents.
Okay. So basically, it's ielts that the want
to these transitional elements and the most famous
is done you.
Because it has 7
electrons. They're are treat. And they lead it's
para,
so it's non magnetic, but it's slightly magnetic,
which is called para.
And because of that, it relaxes water molecules,
and that actually
basic needs to signal enhancement
by the mechanism of
t 1 rated imaging.
Okay. So it reduces the Ti, which is
1 you to demo relaxation time in the
Mri. It's a parameter and super confusing, for
people who familiar. In Mri, usually,
everybody's talking about Ti and t 2 rated
images, and Ti are these beautiful images because
if you have additional contrast agent. They basically
light up bright
We had some kind of problem.
So that they're the best quality images you
can get.
Exactly. Yes.
So... But I guess, you know, there's no
free lunch. There's always some sort of just
disadvantage.
What's the disadvantage of ga as a contrast
agent? So a disadvantage of ga?
I would say, first of all, Ga aluminum
is very toxic, and I forgot to mention
that ga aluminum ions are extremely toxic. So
in order to actually inject them into the
human body, they're being c, so they're attached
to the chemicals
to make them more inert, so they are
actually fixed to these chemicals, so they cannot
make any reactions with anything in the body.
So what happens later, nobody knows if the
leaning
eventually can escape the key later.
But what recently has been found
Well, 1 is that it's causing the kidney
shoes with people who actually have that kidneys
to begin with. And the second is it's
very
specific, so it goes everywhere so it correlates
in the tissue in including the brain tissue
despite the blood brain barrier
which actually protect the brain from the foreign
objects or foreign toxins
that's the purpose.
However,
like with the time, it's actually shown that
it can go through a blood brain barrier.
Even if it's intact and actually it can
accumulate. And I think Fda is still keeping
it very close. I don't got linen and
it's trying to
basically rule out better. There is some consequences
to out. Or it's actually just there and
it's not doing anything.
Yeah. So the food and Drug administration has
has said, don't don't use it unless you
absolutely have to, which I guess, If you're
a cancer patient, then, you know, they benefits
outweigh the costs, but also,
if you're a cancer patient, you're probably having
multiple scans, so any effect of the ga
is gonna be enhanced?
Correct. Yes.
So
what are the alternatives? Are there any alternatives
to get be So basically, so far, there
is.
People came up with these iron monoxide, there
is small iron monoxide nano particles that are,
like, 122
nanometers
size that can mimic.
However, the problem is they only work at
a very low field, which means like 0.5
tesla to 1 tesla
I think now the standard for the clinical
scanner is already 3 tesla, it used to
be 1.5,
but I think in United States it's already
the 3.
So they will not work as good because
they had much fire
monetization than got.
So they will start they will not be
as right.
Right. Okay. Okay.
So I think we're coming up to the
work you did now So maybe you could
just explain what experiment you're were doing and
and what you... What made the Eureka moment,
I guess for you. Oh, I can.
So, basically, I was working, as I said
from the beginning of the...
Let's say, interview,
on the
small capsules
to
to use them for the drug delivery. Choose
them for this targeted on demand drug delivery.
And I was using
nano diamonds because They I wanted to heed
the capsules using magnetic field or the radio
frequency field
Sorry electromagnetic field.
And diamonds were there just to help with
the sheet because they have very high sheet
capacity.
And I was mixing diamond. I was mixing
gutter ingredients, some,
also ga to actually be able to see
them. And then 1 day, I was very
frustrated because ga aluminum kept leaking, and you
can see that it's leaking because all the
son in the background. He's goes to very
bright because God both everywhere. And I said,
okay. No more.
I'll just do without.
And that I was very surprised because
the capsules are are still very bright. And
I said, wow, this must be due to
the diamond.
These small nano diamonds that I was mixing
in the in the capsules.
And then I basically just abandoned my
research
and started focusing on the nano as a
contrast agent because I thought that would be
something big because there are no alternatives.
And now there are these design particles that
all suddenly, you know, have the ti 1
abilities
So from then, on, I think I... For
the 2 years,
basically,
working on the weekends working king all the
time,
I finally yeah, came out with the paper.
We are we put all our efforts
together.
So what are nano diamonds I mean, does...
Is it just was the name sounds? Like
tiny tiny pieces of diamond?
So another diamonds are actually made from d
definition. So,
I think summer in Russia, they were d
the explosives such as Tnt.
And then there is not explosive or
d, I think
and then somebody discovered because they're are full
of carbon
that you actually have
all a sudden appearance of these diamonds.
And then they started cleaning them, and that's
how the diamonds the narrow diamonds came about.
They are very small between... They are actually
very
similar in size between 3 to 10 nanometers
and what else it's interesting. Yes. They're very
cheap because if you're trying to make some
money by getting rid of the explosives,
you actually d them land the diamonds, and
then you can
resell them. And I think 1 gram is
something about, like, 30 euros
so it's not very expensive.
Okay. And how much, you know, supposing them
I'm, I know we're getting ahead of ourselves
here. How much would be used in a
typical sort of dose as a as a
contrast agent.
So a typical dose, I don't know for
humans because they're only work with chicken so
far.
But,
so I would say maybe 10 milligrams. I
don't know. I would have to go back
and complete. But it's a small fraction of
of a gram. So it's you're talking about
fraction. Less than exactly 30 euros to do
the contrast agent for for an imaging. Yeah.
I think the other thing that can be
very interesting with use of nano diamonds, if
you wanna track tumors or something like that.
My vision, of course, you have to check
that because I did not have appropriate tumor
model to check this. The diamonds will accumulate
in the tumors
and then they can stay there and because
they don't need anything. Basically, the contrast is
there just because of these particles, the diamonds,
you can track them, and I don't think
you need to rein inject the patient. So
once you introduce the patient
with Diamonds, you can basically
use these diamonds, let's say, forever
to to reenter to repeat the imaging. And
also, even what's more more the
Research is the
drug delivering using diamonds. I think a lot
of researchers are using diamonds as the platform
because they're are non toxic to actually deliver
drugs.
And I think somebody will have to finally
decide better
such a, like, particulate.
If you have, like, particles as a carrier,
is there advantage from the standard like a
pill. We are, basically, everything is down to
the audience and molecules
here and you're actually dealing with the particles
that are Yes. They are nano sized, but
they're are still particles.
Right. Right? And they have to go out
sun in somehow. So
I think that's also needed... That also needs
to be researched for another because I has
to take these diamonds, they will probably go
kidney, they will go to liver, and then
the question is Gary going to get rid
of them eventually.
So... Yeah. So you Obviously, diamond is just
a form of carbon. So in our bodies
are are made of of carbon. Where carbon
based being. So you would think that you
know, possibly there wouldn't be any toxicity, certainly
not as much as gall, but you still
do have to do the research to find
out.
Exactly.
And also, maybe there is some small opportunity
because these dialects,
I think the collaborator of mine told me
that they were able to dissolve them in
a sulfur acid.
So we have in our cells, like likewise,
and other organ
that he have very high ph, actually, sorry,
very low ph and maybe they can also,
like, these all these diamonds. So
so there could be some reaction that's going
going on. Exactly well some some mechanism to
actually dispose them. Mh. Yes. Because I think
you know, obviously,
diamond is carbon and we're made of carbon.
But you wouldn't want to inhale a bunch
of diamond dust. It would be probably be
very bad for your lungs. So it it
does depend on where where the drug is
or where the the the substance is.
Correct.
So what are the next steps in this
research? You know, you... So you you've shown
that Diamond can act... You know, actually, first
question,
why why do you think the diamond is
acting like a contrast agent?
That is very good question. And I don't
think we still have a very good answer.
1 is... We actually found that issue air
ox them. So you you hidden them further
you actually enhanced 6 times
rate, which is actually quite a lot.
And why is that we still don't to
know exactly. So if there, like,
what people refer to
are the defects in the crystal lettuce So
these are diamond particles. We know that because
we did the text,
test using, like, x rays spec spec,
and other methods, so they are crystals. We
also observed and leonard T, so they have
the crystals structure.
But they probably have some defects in the
crystal structure
And the other possibility
is,
from impurities, like from d destination chamber, they
can have some iron
So maybe from this iron molecules or ios,
did they have the team on
properties we don't well.
So that's also maybe something to
research further
to investigate.
So what are the the next steps for
you? Are you continuing to work on this?
Or if you pass it on to someone
else or...
I think I will still continue because I'm
still super curious well to find out what
exactly makes them
to have these relativity properties.
And also, I would like to use them,
I would love to collaborate with somebody who
has a tumor models to actually see better,
you know, what we are actually guessing that
can happen that we can really use them
to to visualize the geo.
So I would like to establish some collaboration.
And then,
use them for the drug delivery maybe,
and then, of course, go back to my
original s exactly great search.
Eventually.
So what is it about... You know, you
talked about, you know, sort of working, you
know, all all the hours that God sends
to get this paper done? What is it
this sort of keeps you going and is
so excited about this stuff. You know, what
is it
that keeps you going?
Oh, because research is like, rabbit hole you
can go on and on and there is
always some real clue that, like, you go
to bed and you see
I have to try this. And then, literally,
I cannot out do it to come to
work and actually try something.
Or if I put something for scanning,
I would, like, get up in the middle
of the night just to see the results.
So I would say that I'm, like, extremely
curious,
and then it's my curiosity that drives me.
So
simply, I can't wait to see the results.
I would think about something
I mean there are thousands of possibilities.
I was saying these diamonds, I was very
lucky,
more lucky than clever because I will read
something and I would say, oh, this such
a great idea, like air oxidation, I have
to try that, or I would talk to
my colleagues, and they will tell me, but
what about this? And then I will try
that. So
I would say that this group of Met
city is extremely stimulating group. We have so
many smart colleagues.
And it's like super stimulating environment. And then
you're in such an environment, I mean, you
have to succeed.
And I really like how he's making his
students very very successful
individuals. I think when they are finished with
their Phd,
they're already super successful. They have papers, probably
nature science,
all these, like, super high
impact papers.
Or
journals?
Y elena Las.
Thank you very much. I hope you go
down some more interesting rabbit holes in your
career. Thank you.
There was Elena
La
Z
of the Max planck Institute for intelligent systems
in
conversation with Physics World's Margaret Harris.
1 of the most exciting manufacturing techniques to
capture the
imagination
so far in the 20 first century
is 3 d printing.
That's creating an object by adding layers of
material.
Using a computer guided machine.
4 d printing
extends this concept into the dimension of time
as our next guest
explains.
I'm joined down the line from Nottingham Trent
University
by Marty Bo,
who is a senior lecturer in the universities
department of engineering,
school of science and technology.
Hi, Maddie. Welcome to the podcast.
Hi, Hamish. It's a pleasure to be here
today. Thank you for having me. So first
things first, I'm, mad, what is 4 d
printing?
Because I'm guessing probably some of our listeners
have heard of 3 d printing,
but what what is that extra dimension?
Yes. So for the printing
is an advanced form of trade printing or
additive manufacturing.
And introduces time as the forced
dimension.
So this process
involves
painting dynamic objects
that can change their shape, properties
or functionality
in response to external steward,
such as temperature,
light, moisture,
electric, or magnetic fields.
So to put it simply
for the printing is 3 printing of the
smart materials
to create dynamic
structures
that adapt or respond over time.
I see. And can you give us a
few examples of systems that have been created
using for d printing?
Yes. Sure. So a key example of the
4 d printing is self folding a structure.
So these cell falling structures can assemble themselves
when, for example, if we hit them, these
technology technologies is used in many applications, such
as biomedical stands,
So these self expanding your sands can expand
when you deliver them inside the blood cells.
And they opened the blood kind of blocked
arteries.
All another example could be in flat pack
furniture.
So these structures can,
self
assemble themselves, and,
when they... You unpack them.
So another example
is variable
excel. These texts are can adjust
kind of pros.
To regulate the body temperature.
So
another example could be the building ventilators.
So these building ventilators,
kind of, they have adaptive windows, and they
can automatically open and close to regulate the
indoor climates.
Marty, can we go back to the first
example that you gave, and that is of
a a biomedical
stent. Can we talk a bit about how
40 d printed objects are used in medicine.
I I assume what happens is that the
the the object is put into the body
and there it responds to some sort of
change
and activates
itself. Is is that what happens?
Yes. Exactly. So at the moment, we 4
the print biomedical
stands,
so those,
small tubes
And, you know, when when we ages our
arteries,
becomes narrow
becomes narrower. Okay? So for opening that blocked
arteries, we need some kind of devices like
their stands.
So 4 d printed stands can help us
to open those
cages.
Okay? So that's 1 of their applications in
into biomedical
field
And bear in mind,
the the stimulus could be the blood temperature
that can activate the cells and it can
close and it can open
the blocked artery, or it could be magnetic
fist. You can also use the magnetic fields
remotely and activate those stats. So
when it's complete activation, it could be directly,
like, the blood temperature, or it could be
remotely, like the magnetic fit.
I say, And are these 40 d materials?
Is there always some sort of external
stimulus that's required to to cause the change
or or could you create A4D
material that I don't know it. It... It's
it's structure evolves
slowly over time,
without a stimulus.
You know, I'm I'm sort of thinking of
something that's sort of spring loaded and and
moves it mechanically.
Yes, actually. So sometimes,
we need kind of,
external
stimulus,
like the magnetic feed electric field, moisture
temperature so on. And sometimes it's internal
kind of
stimulus. So when it comes to Internet, again,
you need a trigger. As you mentioned, if
if for example, we before the printed structure
and kind of induce some forces inside the
material, Again, we need a trigger.
To release that force to release that the
spring. So
I was say to to my knowledge, we
always need the trigger.
And I I also wanted to have a
chat with you
about work that you've done on 3 d
printed
materials. And and 1 of the things that
you've worked on recently
is the use of 3 d printed
lap meta materials
in self healing asphalt?
So so what is self healing asphalt?
And how can it benefit from the addition
of
advanced materials.
Yes. So self healing asphalt fault is designed
to repair itself.
And close the cracks in the micro and
me scales that naturally developed over time.
So
it extends the as for the life span
and reduces the main maintenance cost. So our
research, that was a collaboration between
universities of nottingham ne,
focus on the use of the 3 d
printed mechanical
materials.
As the innovative solution in the field. So
in,
process, are, I should perhaps introduce mechanical or
materials.
So these
mechanical materials are
engineered my materials with unique and
presented mechanical properties.
So back to your question and our research,
we embedded these mechanical materials into the asphalt.
These materials could a kind of,
help as fault, absorb higher energy. So compared
to the, kind of traditional as far, these
are
kind of,
better in absorbing their energy during you know,
kind of, because of the weight of their
vehicles is that those
dynamic loading.
So we offer them as a replacement to
encapsulate.
So these meta materials
not enhanced self healing
capabilities,
but also mitigate as for unraveling and improved
overall
durability and resilience.
I see. And and when you when you
say that this is put into the asphalt
is is the road
or the pavement still mostly
asphalt with with maybe a bit of meta
material in it or is the meta material,
a significant
chunk of the,
overall
makeup of the of the roadway.
So these are not major elements.
These are minor elements. So we have a
stones, aggregates
as the the to kind of main
on major
elements,
we have mas as a media
And also we embed those
minor elements to enhance energy absorption. So... Because,
you know, wrote as for this, you know,
it's dumb quite long, and then we do
not have capability and even the material to,
make those long
roads, but they are just kind of a
add on.
Right? And so so we can sort of
picture the... I'm picturing the meta material sort
of being in the spaces
between the the stones in the asphalt and
perhaps,
affecting how how how the the system,
responds to force and impacts and things like
that. Yeah. Exactly. Yeah you're right. So they
are kind of,
the, kind of a middleman man. So they
are between the me... They inside the emilia,
and they are between the zones
and because of the flexibility
because they mechanical
materials.
So they provide more flexibility
to absorb their energy compared to their stones.
So have having kind of
20 30 percent of the dose mechanical materials
can enhanced energy absorption
and reduce the kind of, maintenance calls,
clocks
and kind of increase in life.
I see. Okay. And and we we've spoken
a bit about medical
applications. You work on 3 d materials for
medical
applications. Can can you talk about
some of your research in that field?
Yes,
sure. So in the in the medical field,
our focus has been on the design,
and trigger printing of the lattice scaffold
for ortho orthopedic
and
applications. I mean, for the external an internal
use it. Right? So for the orthopedic,
we've developed metal scaffold force, that mimic the
mechanical
and biological called behavior of the bones and
tendons.
So
they are, used to support tissue growth and
regeneration. And they for the organ repair and
replacement
trap.
So on the
side,
we've designed and really 4 the printing devices
like active hand trimmer,
stock suppression
overseas.
So,
we also create,
at the moment, we also create mechanical
lattice phrases for supporting the broken bones or
tendons,
and even most recently
we've, kind of begun trigger painting oral sensing
braces that can
manage
saliva and detect the kind of different diseases.
I see. And and what are the benefits
of of using these
special materials
over, I suppose more traditional?
Materials that are used to make medical
appliances.
Yeah. So
so when come to the
inside the human body,
actually, we well, ddr pioneering technology.
So
at the moment, if you look at it
traditional way for the, you know,
kind of orthopedic.
So they they are mostly using the,
kind of bulky key
metal based things, and and even, you know,
since some some cases we borrow, for example,
part of bone from the other parts,
to replace it. So at the moment, these
technologies
are a kind of pioneering
so they they they kind of held us
to
reduce the rely and the the the body
of the person, imagine if it's elderly,
and they do have,
a lot of bone in their body. So
where to borrow some bones. Right? So some
of them are unique opportunities for us.
To in to enhance the health system and
Health care
quality.
And where come the
application was
outside of the body.
Yeah. For example, we have different braces.
But at the moment,
we use the meta materials and for printing
to reduce the, kind of,
the matter material stage,
the cost of the
production, and also make it customized.
So so when it's to the 3 printing,
we can produce the devices in a kind
of customized way, for the patient, kind of,
specification?
I see. And when when you're designing these
materials, are you are is there any sort
of bio
involved or you. If if if you want
to if you want something that will go
and help a bone heel to you sort
of make it look a bit like a
bone in terms of its structure so it
provides
a scaffold.
Yeah. So by and by inspiration are keys
in the developing those kind of
tissues for regeneration. So
what we do and the many such as
do They look at the, kind of
natural
tissues. They get inspired from the design from
the properties from the materials.
That modern nature or the use. And then
they from the debt inspiration, they try to
mimic a structure
that kind of offer very similar,
mechanical and biological
properties.
Yep.
So, Mad, you're on the editorial board of
the journal,
smart materials and structures.
You give us a few examples
of smart materials and structures
that we haven't spoken about today, and you
would find...
You would find papers about them in the
journal.
Yeah. Sure. So small as and structures are
indeed like magical materials.
Because they have extraordinary in features.
We discussed some of them earlier about the
4 d printing.
And
I can add a few more. So for
example, let's considered the piezo electric materials.
These piezo materials can generate electricity
from the mechanical stress. And,
it's incredibly useful for sensing and energy harvesting
applications. And,
when you apply electric field to these materials
they can induce mechanical stress inside the structure
or material.
Another fascinating group of the small mat materials
is the shade memory atoms and polymers,
so they can return
to the original shit by kind of
activation. It could be again, Thermal
thermal, electrical or magnetic fields. And other class
could be
for crystals. They change the color,
when you expose them to the light.
And
as you can see, these materials are versatile
and have many applications. Ranging from aerospace automotive
to Health,
and we use them actually. So the aim
of using this small materials is
we use them were
adaptive and autonomous behavior we provides significant benefits
So when there's kind of
the, you know, there's a lot of barriers
about the, kind of controlling the situation, For
example, in the space or deep in ocean,
we use this as small materials because they
can offer this autonomous
and
adaptive behavior.
I see. No. That's really interesting. Well, thanks,
Maddie. Thanks for coming on the podcast and
talking about your research and 4 d and
3 d printing and also,
about smart materials in general.
Thank you so much. Hamish for having me
on both,
That was Marty.
Bo,
of Nottingham trent university.
I'm afraid that's all the time we have
for this week's podcast.
Thanks to Marty,
Elena, and Margaret for joining me today. And
a special thanks to our producer, Fred Isles,
we'll be back again next week. But in
the meantime, if you've missed our first physics
world live panel discussion, which was on quantum
sensors.
You still have a chance to view it.
Just click on the Physics world live button
at the top of the Physics World homepage.
And when you're there, you can register for
our next live event, which is on the
20 sixth of September.
Then
we're con a panel of experts who will
ponder the future of particle physics.