Episode 55      19 min 53 sec
Calming Nanotechnology Fears

Dr Amanda Barnard talks about how scientists measure and address the potential hazards of nanotechnology. With science host Dr Shane Huntington.

"Nanoparticles are actually so small that they can pass through our bodies, through cell membranes, which is fantastic for drug delivery. Unfortunately though, from a hazardous point of view, it also means that if this isn't done in a controlled way they can still pass through our body and through our cells and produce protein misfolding or oxidative damage." - Dr Amanda Barnard




           



Dr Amanda Barnard
Dr Amanda Barnard

Dr Amanda Barnard is Future Generation Fellow in the School of Chemistry at the University of Melbourne.  Amanda received her Ph.D. (Physics) in 2003 from RMIT University, on the topic of nanocarbon phase stability. After 2 years as a Distinguished Fellow in the Center for Nanoscale Materials at Argonne National Laboratory (USA) she moved to the United Kingdom, where she held the senior research position of Violette & Samuel Glasstone Fellow at the University of Oxford and an Extraordinary Junior Research Fellowship at The Queen's College. By combining thermodynamic theory and ab initio computer simulations, her research focuses on relating the size, structure and shape of nanomaterials to reactivity and stability for the study of environmental impacts and risk assessment. Amanda is a world renown leader in theoretical and computational nanoscience, and a winner of the 2008 L'Oreal "For Women in Science" award for her work modelling nanoparticles in the environment.

Credits

Host: Dr Shane Huntington
Producers: Kelvin Param, Eric Van Bemmel and Dr Shane Huntington
Audio Engineer: Craig McArthur
Theme Music performed by Sergio Ercole. Mr Ercole is represented by the Musicians' Agency, Faculty of Music
Voiceover: Paul Richiardi

Series Creators: Eric van Bemmel and Kelvin Param

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Calming Nanotechnology Fears

VOICEOVER
Welcome to Melbourne University Up Close, a fortnightly podcast of research, personalities and cultural offerings of the University of Melbourne, Australia.  Up Close is available on the web at upclose.unimelb.edu.au. That’s upclose.u-n-i-m-e-l-b.edu.au.

SHANE HUNTINGTON
Hello and welcome to Up Close coming to you from Melbourne University, Australia. I’m Dr Shane Huntington.

Over the past few decades there has been an extensive interest in nanoscience and new nanomaterials.  The resulting nano technology has many potential benefits for our future but with these benefits comes potential sets of hazards.  The unique and surprising properties of nanomaterials mean that their impact on the world is currently somewhat unknown.  As with all new materials we must determine this impact and put in place safeguards where appropriate.  

Today on Up Close we are joined by one of Australia’s leaders in predicting the hazards of nanotechnology, Dr Amanda Barnard from the School of Chemistry and University of Melbourne, Australia.  Welcome to Up Close, Amanda.

AMANDA BARNARD
Thank you, Shane.

SHANE HUNTINGTON
Now, let’s talk about the term nano first.  We hear it all the time these days.  What does it mean, what does nano actually mean?

AMANDA BARNARD
Well, nano actually means literally a millionth of a millimetre in size.  So when we talk about nanomaterials, we’re talking about the everyday materials we see around us but tiny, tiny little miniature versions of this.

SHANE HUNTINGTON
Now nanoscience, and I guess the end point of that, nanotechnology, has gained incredible interest over the last couple of decades.  Why is that the case?

AMANDA BARNARD
Because there are a fundamental range of properties that nanomaterials have that the big macroscopic counterparts do not possess.  If we can use these properties to create new technologies we can do a wide variety of things that we could never do before.

SHANE HUNTINGTON
Now, let’s talk a bit about the nanoscale.  You know, we’re getting down to atomic level type scenarios here.

AMANDA BARNARD
That's right.

SHANE HUNTINGTON
Why are things different on that scale and how are they different?  So, for example, I have a gold ring around my finger.  Gold is a very inert material in this form.

AMANDA BARNARD
That's right.

SHANE HUNTINGTON
But I’m assuming on the nanoscale it’s very different?

AMANDA BARNARD
That's right, and that's because the surfaces of gold have very different properties to the bulk of gold and your gold ring is dominated by those bulk effects.  If we would take it down to the nanoscale – so we’re looking at particles of gold that contain around 10,000 atoms – then the surface properties dominate and golf becomes a very powerful catalyst.

SHANE HUNTINGTON
What about some of the other properties like colour and texture?  I mean, how do these things change when we change the structure to the nanoscale?

AMANDA BARNARD
Gold is another good example here.  It has what’s called surface plasmon resonances and these surface effects give rise to a variety of different colours.  The medieval stained glass windows that we see in cathedrals around the world are actually coloured using silver and gold nanoparticles.  Of course, back then they had no idea what they were dealing with but it gives rise to these beautiful colours.

SHANE HUNTINGTON
Surface plasmon resonance affects; I’m going to get you to explain that for our listeners.

AMANDA BARNARD
Okay, so that’s the interaction of when light interacts with a surface it creates a wave of electrons on the surface and when these resonances decay they emit light as well, effectively.

SHANE HUNTINGTON
Okay.  What other sorts of things can be tailored on the nanoscale?  What other sort of properties can we deal with?  Can we look at things, for example, like conductivity?

AMANDA BARNARD
Conductivity, for example, we could make a nanowire – that is, the same as everyday wire but something that is only maybe five millionths of a millimetre in diameter.  Depending on the orientation of that wire with respect to the material, we can achieve different types of levels of conductivity or resistance and potentially make much more efficient conductive materials for new devices.  Once you introduce these types of little wires into devices there’s issues around heat dissipation and all kinds of other factors that come into play.  It’s difficult to pinpoint what kind of advancement we’d get by having a particular size or a particular material in a particular device.

SHANE HUNTINGTON
Is a lot of this about us building things smaller or is it primarily about getting different affects out of already known materials?

AMANDA BARNARD
It’s a little bit of both.  We want to make things smaller; using less material makes us much more efficient, there’s a lot less need for natural resources if we can use a little bit less of everything.  But, in addition to that, there are properties that we just can't get any other way.  So, in addition to making things smaller and cheaper and faster, we’re new and novel and different.

SHANE HUNTINGTON
Can you give us some examples of the sorts of things that consumers might be seeing on the shelves already as a result of this work?

AMANDA BARNARD
Okay, the silver nanoparticles are used in sticky plasters for wound dressings.  Because silver nanoparticles are antimicrobial it allows us to heal our wounds cleanly and much more efficiently, and those are available in stores now.  Also sunscreens containing nanoparticles which give us more efficient protection from the sun are available in stores now.

SHANE HUNTINGTON
You mentioned better protection but am I correct in assuming some of these are also clear?  So, rather than having that very colourful, very Australian zinc type cream, you know, where we colour our noses here in the southern land, there are some sunscreens now that work as well but they are perfectly clear to the eye, is that right?

AMANDA BARNARD
Yes, that's right.

SHANE HUNTINGTON
Have they achieved this – I mean, what’s happening there compared to a normal sunscreen?

AMANDA BARNARD
Fundamentally, using nanoparticles means that they’re more efficient.  The nanoparticles can deliver the same protection as the old-fashioned style coloured zinc creams on the nose, but we need much less of them in the cream so we can use a very translucent or transparent lotion and still achieve the same results.

SHANE HUNTINGTON
I want to move now into some of the concerns that are existing around nanotechnology.  I suppose, as with many new areas of science – and this is common among new areas of science – nano also comes with a set of risks that have to be assessed and determined and considered.

AMANDA BARNARD
Yes.

SHANE HUNTINGTON
What is it about nanomaterials that separate them from existing materials – gold being a good example?  We know gold is not problematic environmentally but when we talk about nanogold it’s a different kettle of fish.  What is it about nanomaterials that really, you know, pulls out these concerns?

AMANDA BARNARD
It basically boils down to their surface properties and the reactivity of their surfaces.  The way they react to environment stimuli – being wet, being dry – the way they interact with our bodies or other biological organisms.

When we’ve got a bit piece of it, the surface to volume ratio is very, very low.  So, although we are reacting with the surface, it’s a very minimal effect.  Over time, environment and our bodies have learned to evolve to protect ourselves from this naturally.  But nanoparticles are almost all surface, so the surface reactivity really dominates and because of that, we haven't evolved to be able to cope with that level of reactivity.  We can’t on one side say, these offer a great range of possibilities for new devices, but on the other side say, that we know they’re completely safe and we know everything about them.  Unfortunately, it doesn't work that way.

SHANE HUNTINGTON
I’m assuming with all of these new properties come new ways of interaction with our environment as well.  How can we possibly determine what they’ll be doing when they’re, you know, out in the environment in uncontrolled conditions?

AMANDA BARNARD
That's right, and it is the difference between the controlled environment of a laboratory and the unpredictable, uncontrolled environment of the natural world that poses the problem.  We’re getting very good at predicting in the lab the properties and how to look after them, how stable they are and the way they will behave.  But when we transplant them into a completely unpredictable, random type environment we need to make sure that safeguards are put in place.

Moving from one environment to another creates a problem because nanoparticles will react to their environment.  So somewhere along that path from the lab to the device that we use, and then we ultimately throw it away, things could change.  We need to be able to predict what those changes are along the way so that we know at the end we’ve got what we think we’ve got and our knowledge of safety will still be in play.

SHANE HUNTINGTON
What sort of parameters are we talking about?  I mean, I know reactivity with other materials is one thing, but with nanomaterials I assume we can tailor all sorts of interesting aspects of their interaction.

AMANDA BARNARD
We can.

SHANE HUNTINGTON
Give us some examples of those.  What sort of other things can we tailor beyond just the reactivity of the material?

AMANDA BARNARD
By changing the dimensions of the material we can also induce quantum confinement affects, which means that the electronic structure of the material is confined by the fact that it is finite.  This means that the band gap which is used for electronic devices, for example – semiconducting devices – can change; it can go larger so a semiconductor will become an insulator, or it can shrink and then a semiconductor could become a conductor.  So by tailoring the type, the shape, the size and the structure of the material we can also tailor its fundamental properties as well.

SHANE HUNTINGTON
Many of these characteristics would be presumably affected by changes in temperature and pressure and so forth when released in the environment.  Do we have an understanding of how that would affect some of these nanomaterials?

AMANDA BARNARD
No, not at this stage.  This is an enormous problem to deal with.  There are so many different possibilities in our natural environment; we’re talking about a multi‑multidimensional problem to deal with and to test all possible permutations in this space is not possible.  In order to do that, what we really need is predictive models to highlight areas that we should be doing the experiments in.

SHANE HUNTINGTON
I understand there have already been some indications that in certain fish tumourous growths can be, I guess, initiated as a result of exposure to nanoparticles.

AMANDA BARNARD
Yeah, the fullerenes can pass through the blood-brain barrier and product oxidative damage in the brains of fishes.

SHANE HUNTINGTON
Right.  This is a scenario where a simple carbon molecule, is it –

AMANDA BARNARD
Right.  C60, 60 carbon atoms.

SHANE HUNTINGTON
Yeah, is entering through so it’s actually making it through that protective area of the brain.

AMANDA BARNARD
Nanoparticles are actually so small that they can pass through our bodies, through cell membranes, which is fantastic for drug delivery – just think of the medical implications of being able to target a nanoparticle to a tumour within the body.  Unfortunately though, from a hazardous point of view, it also means that if this isn't done in a controlled way they can still pass through our body and through our cells and produce protein misfolding or oxidative damage, for example.

SHANE HUNTINGTON
How do we protect against that sort of threat?

AMANDA BARNARD
Ultimately, they’re going to enter the environment because we’re using a lot of biodegradable products.  The way to protect against that is to modify the structure, the shape and the size to protect ourselves.  Also looking at different ways of coating them so as to reduce their reactivity, so that when they are introduced into the body they’re benign and they don’t create any inflammatory response.

SHANE HUNTINGTON
As scientists – and I include myself in this group of people – we have made a few mistakes over the years.

AMANDA BARNARD
Yeah.

SHANE HUNTINGTON
I think asbestos and DDT are probably ones that people think about.  How do we respond to the concerns of the general populace with regard to nano, given, as you say, there’s so much we don’t know?

AMANDA BARNARD
The important point, I think, to reassure the public is that Governments all around the world are aware of this problem and they are starting to put into all of their science funding, specific funding to look at these issues.  This means that for all the scientists out there creating the next generation of wonderful devices, at some point the toxicology will be checked so that the most safe version of those devices is the one that ultimately reaches the shelves.

SHANE HUNTINGTON
You're listening to Melbourne University Up Close.  I’m Dr Shane Huntington and we’re speaking with Dr Amanda Barnard about nanohazards.

Amanda, many of these materials are incredibly new and surprising in terms of their applications and their functions.  Now, you work on the modelling of these materials and how that will give us information about what they will do when they’re in the environment.  How do you do that?  How do you model something so complex?

AMANDA BARNARD
Okay.  There’s a combination of two features; one is a theoretical model, which is basically a lot of math, and then a parameterization of that.  The equations contain a number of materials properties, for example, that pertain to a specific nanomaterial.  These can either be obtained by experimental methods where available or, in my case, I calculate most of them using highly accurate first principal supercomputer calculations.  Then, plugging those in, we can use those models to rapidly sample structure space.

SHANE HUNTINGTON
What sort of properties about these materials do you need to sort of have an understanding of before you can actually model them?

AMANDA BARNARD
In my case, looking at thermodynamic modelling I need to know all about the materials properties and, in particular, the surface properties because the surfaces dominate nanoparticles in terms of their stability and reactivity.  By calculating a range of different surface properties and inputting them into the model, it’s possible to see how they may respond if they’re heated up, if you get them wet or if they’re exposed to air, of course, which are all things that in the natural world they will be exposed to.

SHANE HUNTINGTON
Let’s talk a little bit about thermodynamic modelling.  What exactly is that, how do you go about that?

AMANDA BARNARD
Well, in my case it’s a geometric summation – so a summation over the geometric features of the particle such as the facets, the edges, the corners and it sums up all their energetic properties from an equilibrium standpoint.  So we’re looking at, ideally, if the nanoparticle was given enough time and perturbation what would it prefer to be, what sort of structure would it prefer to adopt?

SHANE HUNTINGTON
Then you give it some sort of external stimuli to see how it will react?

AMANDA BARNARD
That's right.  So maybe we heat it up, so we’d look at how that structure might change as a function of temperature and optimise the shape and the phase along the way.  If there’s a phase transition or a fundamental change in the shape as a function of temperature then we might pinpoint at 500°C we may have a problem here – experimentalists go away and check out this nanoparticles at 500°C, for example.

SHANE HUNTINGTON
Right.  Can you give us some examples of the nanoparticles you're examining and which ones are of interest?

AMANDA BARNARD
Okay, well actually about to come out in the American Chemical Society journal, ACS Nano now here at the end of 2008 is the first phase map for titanium nanoparticles.  This actually maps the preferred phase anatase or rutile in a size‑temperature manifold.  Therefore we can sort of basically pinpoint at a given particle in water, so it actually shows the change in the phase stability line as a function of surface chemistry.  So in water what can we expect the stable phase to be if we were to heat it up over a range of temperatures?

SHANE HUNTINGTON
Okay. Anatase and rutile.

AMANDA BARNARD
Anatase and rutile.

SHANE HUNTINGTON
Yeah.  The detail on that?

AMANDA BARNARD
They’re both titanium dioxide, titanium-2 oxygens.  They both tetragonal, which means they both have the same crystal system, but they have a different structure which means that the atoms arrange in a different way.  This gives rise to different properties.  They’re both photocatalysts, so they both react with light, but one of them is used in the self-cleaning glasses and things like that and one of them is used in sunscreens.

SHANE HUNTINGTON
Right.

AMANDA BARNARD
One of them is nice and reactive and produces free radicals so that your glasses self‑clean but that’s not the one we want on our skin.

SHANE HUNTINGTON
Now, I know from my high school days that the periodic table has not changed too much over the last 20 or so years with, you know, minor amendments here and there.  Are we looking at producing almost a second periodic table of the nanoelements and the way in which they would interact and what we should expect from them on the nanoscale?  Is that where we’re heading with this sort of thing?

AMANDA BARNARD
Yes, that is where we’re heading but, unfortunately, this brand new periodic table is pretty empty right now because we don’t really know what to put in it.

SHANE HUNTINGTON
Right.  We hear people talking a lot about the safety of nanomaterials and nanotechnology and for the end user.  One thing we never hear about is the safety for the people in the lab.  In fact, when we go to an average chemistry laboratory anywhere around the world we would find material safety data sheets pinned up everywhere indicating what the materials could possibly do to them, what the hazards are and what the actions required, should people be exposed, would be.  Is the same set of sort of information becoming available for researchers that are working on nanomaterials?  How do we keep up-to-date with that, given they are the ones constructing them?

AMANDA BARNARD
This is a very difficult problem.  Currently there is not a complete set of safety sheets for nanomaterials for workplace safety.  There are people working on this issue and there are a number of institutions around the world that are collecting together the information to start to create this type of framework.  People that are working in the labs, of course, are well aware of the potential hazards and are adopting somewhat of a cautionary approach to the problem – perhaps overprotecting themselves, in a lot of cases, to make sure that they’re not at risk.

SHANE HUNTINGTON
You're in the theoretical sort of area of this work.  Is there a group of people in that area pushing the sort of knowledge of what these nanohazards would be or is it a relatively new field, just as nano itself sort of was 20 years ago?

AMANDA BARNARD
Well, I think it’s maybe relatively new – either that or they’re out there and they’re hiding and I can't find them.  But I find myself quite alone in respect of a theorist who’s sort of thinking about these imminent problems.

It is an area where theory and experiment can work very well together.  Ultimately, the theoretical models we need to look at environmental impacts need to be fed from experiment to highlight how to make them more realistic and more reliable.  In the same way, the theoretical modelling will indicate what areas are of concern so the experimentalists are using all of their resources to tackle the most important problems.

SHANE HUNTINGTON
Dr Amanda Barnard, from the School of Chemistry at the University of Melbourne in Australia, thank you very much for being our guest on Up Close today and I certainly hope that your work continues, is a success and keeps us away from those nanohazards where they are.

AMANDA BARNARD
Thank you, Shane.

SHANE HUNTINGTON
Relevant links, a full transcript and more information on this episode can be found on our website at upclose.unimelb.edu.au.  We also invite you to leave your comments or feedback on this or any episode of Up Close.  Simply click on the ‘add new comment’ link at the bottom of the episode page.  Melbourne University Up Close is brought to you by the Marketing and Communications Division in association with Asia Institute of the University of Melbourne, Australia.  Our producers for this episode were Kelvin Param and Eric van Bemmel, audio recording by Craig McArthur, theme music performed by Sergio Ercole.   Melbourne University Up Close is created by Eric van Bemmel and Kelvin Param.  I’m Dr Shane Huntington.  Until next time, goodbye.

VOICEOVER
You’ve been listening to Melbourne University Up Close, a fortnightly podcast of research, personalities and cultural offerings of the University of Melbourne, Australia.  Up Close is available on the web at upclose.unimelb.edu.au, that’s upclose.u-n-i-m-e-l-b.edu.au.  Copyright 2008 University of Melbourne.


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