Lab Profile: Dr Natalie Plank, Victoria University of Wellington

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Dr Natalie Plank leads the Nanomaterials Devices Group at Victoria University of Wellington, and is a Principal Investigator of the MacDiarmid Institute  Her group explores low cost fabrication techniques for nanomaterial devices. She is interested in using carbon nanotubes and nanowires for sensing and other electronic applications. Laurie Winkless spoke to her to learn more about her work…

What is your academic background?

I did astrophysics at The University of Edinburgh for my undergrad, but by the end of my final year, I’d realised that I was more interested in atomic and molecular physics. One of my lecturers pointed me to the Engineering department, where Prof Rebecca Cheung had just started her research group. She agreed to take me on for a one year research masters, where I’d work on etching silicon carbide. Moving from astrophysics to a much more practical science was a bit daunting, but Rebecca was very supportive. I was also lucky to learn from Alan Gundlach, who was a guru on all things microelectronics. During that year, I spent a few months at TU Delft, in Dr Emile van der Drift’s group. It was amazing to get that sort of training so early in my career.

One benefit of being in Delft in the early 2000’s was that the Cees Dekker Group there had started doing interesting stuff on carbon nanotubes (CNTs). I was only a student at the time, but I’d heard about it and it all sounded really exciting. I went to a conference on the topic when I got back to Edinburgh, and was totally hooked. I wrote up my masters, and started a PhD on carbon nanotubes in Rebecca’s group.

One of the most memorable experiences of my PhD was the six months I spent in Japan. At the time, our lab had close links to NEC, so when I was given a travel scholarship by the Royal Society of Edinburgh, I used it to go to NEC Japan. I worked in the group of Sumio Iijima, the discoverer of carbon nanotubes. It was such a fun, formative trip, and it gave me a taste for travel.

Did you ever consider working in industry?

Briefly, after finishing my PhD. Because things had gone reasonably well, I had some papers, and there were good options to stay in Scotland. But I was a bit young and restless, so I started looking further afield. I was eventually was offered two jobs, one at Philips Research in Leuven, and the other a postdoc at the University of Cambridge. Both were really good options, but in the end I chose the academic route, and went off to Cambridge. There I worked on solar cells with Prof Sir Mark Welland, in close collaboration with Prof Sir Richard Friend's group, for just over three years.

What brought you to New Zealand?

I met my now-husband (Professor Justin Hodgkiss) when we were both doing postdocs at Cambridge. It got to a stage where we’d both decided we wanted a change. Justin is a kiwi and I’m a scot, so we were looking in both places. Justin was the first to get a permanent job offer, here at Victoria University of Wellington. We looked into New Zealand a bit more – my PhD supervisor had started her career here, and had lots of good things to say about the country. I was also interested in what the MacDiarmid Institute were doing – it’s a virtual institute that encourages open collaboration across NZ materials science – and it sounded like it could be a good environment. So, we made the move, and have been here since 2009.

When did you join Victoria University of Wellington?

Very early on. I was offered a one-year postdoc position with Prof Joe Trodahl and Assoc Prof Ben Ruck, to work on thin film growth. That led to me being asked to build a new cleanroom fabrication facility here at the university, which still amazes me! At around the same time, I was granted a Foundation for Science Research and Technology (FRST) postdoctoral fellowship, and I got a Marsden Fast-Start grant. That was the springboard to starting my own research and setting up my group.

What are the major themes of your group’s research?

Everything is about nanomaterial electronics. I'm especially interested in what you can do with random networks of nanomaterials. I’ve used carbon nanotubes and nanowires as different types of sensing platforms. Some of my research is quite fundamental, for example, I want to understand more about the physics of conduction in these devices. But my work has lots of different applications.

One of our current projects, supported by the Marsden Fund, is in collaboration with Prof Colleen Marlow at Cal Poly SLO and Assoc Prof Charles Unsworth from The University of Auckland. We’re using aptamers on networks of carbon nanotubes to sense hormones, so oestrogen, progesterone, and testosterone. Ultimately, we want to use that as a blood test platform, but it might also be interesting for water contamination.

In addition, we’re working with Plant and Food Research, with Dr Colm Carraher and Dr Andrew Kralicek. We take odorant receptors from fruit flies and stick them onto our CNTs – we’re basically making ‘electronic noses’ that can detect a wide range of odours. And my MacDiarmid research, in collaboration with Professor Simon Brown, is on using random networks of silver-silver sulphide nanowires for neuromorphic computing.

What’s the secret to running a successful lab?

For me, it’s treating everybody as a person; an individual with different needs, skills, and priorities. Everyone does things slightly differently, but I think about how we can work together to tackle a problem. I was lucky to have a kind, supportive PhD supervisor, so I want to do the same. And I think because I’m quite sensitive, I expect other people to have feelings too – I don’t get angry over unimportant things. I also like to set expectations, and have regular catch-ups with my students.

At the moment the group includes one postdoc and three active PhD students. I've got one PhD student who's just finishing up, and another one due to start in January. We usually take on a final year undergrad or master’s student every year too. That size of group tends to work well for me, both in terms of getting access to the fabrication facilities, and just from a people management point of view.

Selected publications

Thanihaichelvan Murugathas, Han Yue Zheng, Damon Colbert, Andrew V. Kralicek, Colm Carraher, and Natalie O. V. Plank, Biosensing with Insect Odorant Receptor Nanodiscs and Carbon Nanotube Field-Effect Transistors, ACS Applied Materials and Interfaces, 2019, 10.1021/acsami.8b19433

Thanihaichelvan, M., Browning, L.A., Dierkes, M.P., Roger Martinez Reyes, Andrew V. Kralicek, Colm Carraher, Marlow, C.A., Plank, N.O.V. Metallic-semiconducting junctions create sensing hot-spots in carbon nanotube FET aptasensors near percolation, Biosensors and Bioelectronics, 2018, 130, 408-413

Maddah, M., Unsworth, C. P. & Plank, N.O.V. Selective growth of ZnO nanowires with varied aspect ratios on an individual substrate. Materials Research Express, 2018, 6, 015905

C. P. Burke-Govey, U. Castanet, H. Warring, A. Nau, B. J. Ruck, J. Majimel and N. O. V Plank. Realizing field-depending conduction in ZnO nanowires without annealing, Nanotechnology, 2017, 28,124003.

H.Y. Zheng, O. A Alsager, B. Zhu, J. Travas-Sejdic, J.M. Hodgkiss, N.O.V. Plank. Electrostatic gating in carbon nanotube aptasensors, Nanoscale 2016, 8 (28), 13659-13668.

Han Yue Zheng, Omar A Alsager, Cameron S Wood, Justin M Hodgkiss, Natalie OV Plank. Carbon nanotube field effect transistor aptasensors for estrogen detection in liquids, Journal of Vacuum Science and Technology B 2015, 33: 06F904. [Editor’s pick]