Professor Frank Caruso, physical chemist and materials scientist

Physical chemist and materials scientist

Professor Frank Caruso

Professor Frank Caruso completed an honours degree in physical chemistry at the University of Melbourne. In 1994 he received a PhD for his research into the dynamics of molecules. He then took up a postdoctoral fellowship at the CSIRO Division of Chemicals and Polymers to study how to modify surfaces to enable the detection of specific molecules.

In 1997 he was awarded an Alexander von Humboldt Research Fellowship to work at the Max Planck Institute of Colloids and Interfaces in Berlin. There he developed a strategy to modify the surface of nano-sized colloid particles, using the technique of self-assembly. The resulting nanoparticles can function in new roles (eg, biosensors) and can be used to fabricate advanced materials.

Caruso has received medals from the Royal Australian Chemical Institute (2000) and from the Royal Society of Chemistry-Royal Australasian Chemical Institute (2001). In 2002, Caruso received a Federation Fellowship to return to Australia as Professor in the Department of Chemical and Biomolecular Engineering at the University of Melbourne.

Interviewed by David Salt in 2002.


A new focus in nanotechnology and biotechnology

Frank, after five years of working in Germany on nanotechnology and biotechnology, you have just returned to a new position in Australia. What is your new job?

This job is as a Federation Fellow in the Department of Chemical and Biomolecular Engineering at the University of Melbourne. It will involve performing research in nanotechnology and biotechnology, and also teaching.

It is great to be back in Australia. This country has given so much to me, in terms of education and other things. I am very much looking forward to collaborating with colleagues here and to making innovative progress in the science that we will be doing at the university to contribute to Australian society.

You have been lured home with a prestigious Federation Fellowship from the Australian Research Council. Why are nanotechnology and biotechnology seen as such critical areas of research for Australia?

Well, because matter behaves very differently at the nanolevel, one can exploit the properties of matter in order to derive functional systems or materials that otherwise would not be possible. It has been recognised around the world that such research has huge implications, and Australia has now started to heavily fund research in this area. For me, it is great to be involved in nanoscience and nanotechnology, and if you go a step further and couple them to biosciences, then you also start to open up new possibilities in the biological sciences. You can do marvellous science which should have a positive impact on Australian society – and the economy – when new companies are formed as a result of discoveries that originate from that research.

So, in nanotechnology, what scale is a nanometre?

Effectively, the nanorealm is about 1 x 10-9 metres – a billionth of a metre, remarkably small. Usually it is defined as lying between one nanometre and 100 nanometres, which is between 1 x 10-9 metres and 100 x 10-9 metres. In order to see some of these systems, or particles, one would typically need to use electron rather than optical microscopes.

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An exciting pathway into nanotechnology

What led you into this exciting area?

My starting point in science was a decision to pursue science as my major subjects – chemistry, physics and mathematics – at high school. I was very much motivated by the encouragement and enthusiasm shown by the excellent science teachers there. It was exciting to be in chemistry and physics practicals, and to learn about the mathematics behind a lot of these subjects. I really enjoyed the possibility of discovering new things and trying to understand how things work.

What did you study at university?

After high school I went to the University of Melbourne and did a science degree, majoring in chemistry. That was extremely exciting. I then moved on and did my honours degree with Professor Franz Grieser. He has been an excellent scientific mentor, and has guided me significantly in my scientific career. And as a result of that, I conducted a PhD in physical chemistry at Melbourne University, from 1991 to 1994.

Is physical chemistry a good pathway to follow to get into nanotechnology?

Physical chemistry is one pathway, yes. It’s an excellent way forward. Chemistry in general, physics, engineering, mathematical sciences also, can lead you into different areas of nanotechnology, as can biology, biochemistry – a whole range of different science subjects can be studied, to move into nanotechnology and biotechnology. I believe the pathway to nanotechnology, nanoscience, is through a science degree, an engineering degree or a related degree in those areas.

Postdoctoral experience: surfaces for biological detection

Following university you did a couple of years with CSIRO Chemicals and Polymers. What were you working on there?

I was looking into designing surfaces for biological detection – effectively, taking surfaces and modifying those specifically to detect biological specimens or analytes, or drug compounds, for example. That involved a lot of surface chemistry, a lot of protein science, and it proved to be very fruitful. It resulted in quite a bit of scientific know-how, which was what the projects were aimed at, and elements of the research have been integrated into other projects at the CSIRO. And I understand that some of the biosensors which have subsequently been developed are about to be marketed.

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A big move: nanoengineering in Berlin

In 1997 you made your big move to Berlin, to work at the Max Planck Institute of Colloids and Interfaces. Could you tell us a little about that?

I was awarded an Alexander von Humboldt Research Fellowship. The Humboldt Foundation funds foreign researchers in Germany. There are many Max Planck institutes in Germany – more than 50 – and I moved to the Max Planck Institute of Colloids and Interfaces, in Berlin. It is a marvellous establishment, with approximately 200 scientists, including staff and technical assistants. It provides an excellent environment of high-quality scientists from around the world to conduct cutting-edge and world-leading research, and it provided a basic foundation for me to perform science in an area that I was interested in. So I was funded by the Humboldt Foundation, and had infrastructural support and additional support from the Max Planck institute. The section I was working in was directed, and still is, by Professor Helmuth Möhwald, who has been another excellent and pivotal scientific mentor in my career.

For me it was a wonderful move, not only because many of the things that we performed scientifically have attracted world attention, but also socially. I really appreciated this excellent opportunity to move to the other side of the world, the northern hemisphere, and experience a different culture, a different language. Berlin itself is a very diverse, multicultural city, very cosmopolitan, and it broadened my view of life in many ways. So it was an exciting time, professionally and socially.

Did you make any scientific breakthroughs while you were in Berlin?

There were a number of scientific breakthroughs that have been considered as significant. Some were basically on how to modify colloid particles – even very, very small particles in the nanometre regime, between about 50 x 10-9 metres and about 100 nanometres in diameter. We developed a very versatile and flexible strategy to modify the surfaces of these particles and introduce new functionalities to them, using self-assembly. And in doing so we have created a whole range of new colloid or nanocomposite particles that we are now interested in using to self-assemble into other structures to fabricate advanced materials.

The effects of reducing materials to the nanoscale

Let’s look a bit more closely at some of the concepts you have been referring to. For example, how do things behave differently at the nanometre scale?

An example related to my group’s area of research would be metals. Many people would be familiar with the fact that a gold metal film can be reflective and has a yellowish appearance. If you have the same material sized down in the form of particles in the nanometre range, these particles exist, for example, in an aqueous solution and they can be red in colour. So they have totally different optical properties – on one hand you have a yellowish reflective coating; on the other hand, in the nanoregime, it is a colloidal dispersion, which to the eye appears red. That is an example of extreme differences that arise. And there are many analogous examples of differences in optical properties, in electronic properties, in magnetic properties and others, simply as a result of going down in size for these and other materials.

So a lot of nanotechnology is about trying to work out and exploit the properties of the substance when you take it from its bulk form and reduce it to nanometre-size particles?

Yes. That’s precisely what is interesting in nanotechnology, that material at the nanoscale level behaves very differently from similar material which is not at that scale. And one can utilise those properties to create advanced systems, structures, materials, for various applications.

Manipulating nanoparticles and nanosystems

How do you manipulate objects at the nanometre scale?

This is very challenging. A variety of techniques are used. Some involve state-of-the-art instruments – specifically-designed microscopes and others – but self-assembly, under controlled conditions, can also be used to manipulate some of these materials.

Self-assembly is essentially the ability for compounds or species, or materials for that matter, to assemble by themselves into various structures. Nature is full of examples of self-assembly, for example coral, a whole range of different materials. Self-assembly is very important because it enables us, in many instances, to prepare structures that otherwise we would not be able to. New avenues and methods are becoming available now to manipulate nanoscale systems in order to form advanced structures, but self-assembly provides a flexible and viable approach to creating structures by taking these nanoparticles or nanosystems and allowing them to assemble, on their own, into a desired final material or product.

So, for example, if you take a surface and pattern it with various functionalities, then you can assemble some of these nanocomponents onto certain areas on that surface. You can use pre-formed surfaces or you can use specially designed mechanical manipulators, but it is extremely challenging. This is where I believe there are going to be significant advances in the near future.

In our research we manipulate the materials through controlled assembly, in essence modifying the properties of the colloidal dispersions, through salt and pH – acidity, basicity of the solution – and that enables the dispersions to behave differently.

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Possibilities presented by colloid particles

So what are colloids, and why is it important to be able to modify their surface properties?

Colloids are particles dispersed in a different phase, and they are present all around us, for example in milk, paints and also fog. The simplest case, of particles dispersed in water, is known as a colloidal dispersion. And if you would like to administer drugs to a body, for example, you can have colloidal drug delivery systems. If you can nanoengineer particles – that is, introduce new properties, new functions to those particles – you can manipulate those particles in terms of how much drug can be loaded and how the drug can be released in various applications. That then should have immediate translation to medicine in the area of drug delivery. That simple example is a very important one, as there is immense scope for improvement, just in being able to modify and control particles in solution.

Are you talking about loading the drug into these colloid particles?

Yes. There is a variety of colloids that one can make or modify. Some of these can be solid colloid particles, or they can be hollow. In the case that they are solid, one can imbed the drug within the particle; in the case that they are hollow, one can infill the particle with the drug. So you can infill or you can imbed in a different matrix or material, and then release those under certain conditions.

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Applying nanotechnology to the biosciences

Where is your group’s work heading?

My group’s current focus is on manipulating particles in solution to form advanced structures and functional materials, and also manipulating those particles in solution in order to target various biological applications. We are looking at moving into the biosciences, preparing advanced drug delivery systems, functional biocatalytic systems – in essence, the biological sciences, with the application of nanotechnology in those specific areas.

Would functional biocatalytic systems be used to speed up other reactions?

Yes. In essence, you can perform biocatalysis with enzymes that are deposited on a solid support, for example glass. To have those enzymes on particles represents a much more attractive system because particles in themselves have a much higher surface area, which you can utilise to get a much higher activity or bioactivity for your system. And that is attractive for a variety of technological reasons.

However, one must understand the basic science behind these systems. How can one put multishell components on particles, in a sequence where one is putting multiple layers of enzymes on particles and keeping each particle dispersed, or as an individual entity in solution? So we are working through ways in which to give these particles uniform coatings, to keep their stability as such and to apply them in biocatalysis, for example.

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A long-term vision for Australian research

What is your vision for your group at Melbourne University?

A long-term vision would be for the group and the department that I am in, and other associated departments, to be recognised as one of the leading centres for nanoscience and nanotechnology, including biotechnology, in the southern hemisphere – to compete at the global scale, internationally, and to undertake cutting-edge, innovative research.

Besides drug delivery, what sorts of real-world applications are there for this research?

Nanotechnology will impact on many things in society, from the way we are entertained – computer systems, television, media – to the way we travel, such as by aeroplanes made of advanced new superstrong, lightweight components, painted with new kinds of paints and using new types of computer systems.

Nanotechnology is widely and broadly applicable to a range of areas. It is an enabling technology – its breakthroughs and discoveries will be translated into various aspects of society.

Where does Australia stand in the world of nanotechnology?

Australia is putting significant funding into nanotechnology. The US leads the world in funding for the area, Japan is very much up there, and Europe is also increasing its funding. So it is timely that the Australian government, through the Australian Research Council and other initiatives, is increasing the funds available in Australia for such research. There are various examples of areas of nanoscience and nanotechnology where Australia is leading the world; however, I would say there is enormous scope for improvement.

Funding, though essential, is only one element of successful research. People are very important. Talented, skilled scientists are crucial to successful research. The flexibility and creativeness of Australian scientists, together with increased funding, should provide a unique and attractive environment for nanotechnology and nanoscience in Australia for the future.

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Gaining enjoyment, motivation and enthusiasm in the science world

What do you get up to outside of work?

I enjoy sports – cycling, running, tennis and squash – very much, but one of my favourite things is to travel. Science, being an international career, has given me the opportunity to move to Berlin, and I’ve had a wonderful time there. I have explored many different countries during my time in Europe and that has provided me with a wonderful learning experience and many friendships with people of various cultures. It has been absolutely marvellous.

It used to be said that to see the world you should join the Navy! Do you think it is important for young people to spend some time overseas in their science careers?

Yes, one of the main reasons being that it can give scientists a greater appreciation for the international nature of science and for the types of science being done in different countries, different institutions or universities. They can interact with scientists who have diverse backgrounds but for whom the common ground is the science. It is fascinating to see people from different countries so motivated and enthusiastic about science, regardless of where they come from. For me that was very exciting, and there was also an element of the science being relevant, people on the other side of the world being interested in science that is being done on this side of the world.

Taking up a career in science provides a wonderful opportunity to travel – not only to be located at a given university or institute, but frequently to attend conferences and meetings all over the world.

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Bringing together the ingredients of success

What are the ingredients of your success?

I think it is important for a scientist to have excellent scientific mentors and excellent colleagues, and also to be motivated and focused. Also, in my view, success in science requires an element of creativity to be present. To move through science, these elements are certainly important, but they are not necessarily the only ones.

It has been very helpful for me to have mentors throughout my scientific career, and also to benefit daily from being with fellow scientists who are highly motivated and very interested in what they are doing. If you are in such an environment it is great. And it works well for science.

So the secret is not just what you do, but also the type of people you associate with?

I believe the environment in which a scientist works is very important. And to have expert, world-leading scientists around you is a bonus, an important motivating factor.

Would you recommend nanotechnology to today’s science students?

Yes, because nanotechnology is an enabling technology, and a technology of the future. I studied science because I found science interesting, so I was enthusiastic and motivated about it. Now that I find myself in this area – nanotechnology, nanoscience – I am enjoying it very much. I would certainly recommend students to look at it as a serious option for the future.

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