MESA+ University of Twente
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Maarten van Megen (promotion date: 12 July 2013)

Redox cycling at nanospaced electrodes
Towards electrochemically amplified biomolecular sensing

Promotion date: July 12.

Promotor: Albert van den Berg

Assistant promotor: Wouter Olthuis

Molecule synthesis is convenient on the small scale while electrode fabrication is more convenient on the large scale. In this project they meet each other halfway for the development of a twin electrode design featuring surface attached molecules undergoing redox cycling. Research has focused on novel applications of the redox cycling phenomena, fabrication of electrodes with an inter electrode spacing in the nanometer range, and the electrochemical behaviour of surface attached ferrocene labelled polyethylene glycol (PEG). This knowledge is combined in experiments where the PEG molecules are cycling between two electrodes spaced < 100nm apart. This setup can be used as the transducing element of an electrochemical sensor if the molecules are labelled with an additional recognition element.

Was your research application oriented or more fundamental in nature?

It turned out to be more fundamental than expected, so to say. We thought it a good idea, and feasible indeed, to combine two techniques. Attaching electrochemically labelled polymers to an electrode and redox cycling. Depending on the polymer used, this could give information on the amount of molecules present in the solution. In this way the setup would, for example, be able to function as a new kind of DNA sensor.

In trying to realize this kind of platform, it turned out some additional parameters were involved, making this principle function differently and less stable than was expected beforehand. Therefore we changed our strategy, in a successful way. We found a good theoretical model that we analysed and simulated thoroughly, and which we were able to validate by experiments and measurements in a nice way.

I’m convinced in the future these combined techniques will prove beneficial in their sensing capabilities. Then, the way towards applications will be open as the chips for this kind of redox cycling phenomena are already existent.

In what way did you develop personally, as a researcher and scientist?

At the beginning of the thesis project, I was lingering in theory for too long a time, building experiments only after understanding the theoretical backgrounds completely. It turned out that this method was slowing down the scientific progress too much. It is much more efficient - especially in my field where the experiments are relatively easy to construct– to do some bold experiments in a quite early stage already. This is a matter of attitude that develops along the way. One cannot learn it in one day. It takes some time.

Also I learned a big deal of chemistry, an area of research I was unfamiliar with when starting the PhD work. The experimental skills, I learned mostly along the way as nice colleagues helped me out a lot. The theoretical knowledge in the field, I focussed on during the first year of the project. In scientific literature I managed to find all relevant issues quite well. I assume this is one of the most important skills one is building up in this period of life: being able to quickly master the knowledge and relevant skills in a specific branch of research. This skill remains useful as most research, in academics and in industry, is multidisciplinary in nature. This means that wherever you go next, there will always be contact with fields that are new to you.

What are your future plans?

When I started, I was ready to go and work in industry. Then they offered me this great opportunity as a PhD student. Now it is completed, I would like to work in R&D in industry, favourably in sensor or signal processing technology. The precise setting can be manifold and is of minor importance to me. I would like to be involved in developments close to market applications. It will be a nice change compared to my current project, to be able to explain my daily work at social gatherings, and showing in what products my contributions will be present.

Did you feel part of the Mesa+ community during your PhD project?

Yes, very much so. The BIOS group in itself is quite multidisciplinary. In my project I collaborated nicely within Mesa+, for example with the Molecular Nanofabrication Group which helped me a great deal in fabricating the molecules while I was concentrating on the devices. Also the Nanoionics group was of great help, allowing me to perform measurements on their setup.

Being a member of Mesa+ and working in the great cleanrooms, makes it an easy job profiling oneself on a national or international level. I guess, the outreach activities Mesa+ offers should continue, for example by giving demonstrations and being present on various events. The visibility in the region is important in my view. In that way everyone can identify with the work Mesa+ is doing, especially the public in Twente and in the Netherlands.

Creativity is important here. It isn’t a good thing if Mesa+ is positioning the institute in a style that is never changing for years and years. So, I hope Mesa+ will succeed in surprising the public time and time again.