Profile

Albert van den Berg

Professor of BIOS, The Lab-on-a-Chip Group, MESA⁺, University of Twente, The Netherlands

I live in a nice small town called Nijverdal in the eastern part of Holland with my ever sunny wife, Trudy Vos, and three great kids: Line (11), Joran (8) and Remo (5). In our life, we try to combine two careers with an intensive and happy family life, and with both Trudy and myself being home one day per week, I believe we have quite well achieved this goal. The place where we live is located just in between our places of work, and one of the few areas in our flat country with slight elevations (I would not even dare to call them hills) covered with forests. Hills and mountains have always been a part of my favorite hobby: cycling, hiking or skiing in the mountains are activities I cannot live without.

I was born in 1957 in Zaandam, an industrial town close to Amsterdam, surrounded by several ‘polders’ (regained land below sea level), where I grew up with three brothers. Playing football, rowing and swimming in the summer and ice-skating in the winter were among the preferred things to do, while in the mental domain I was a reasonably talented chess and bridge player at a young age. I have always been interested in technical topics, not least as a result of the continuous stimulation of my parents; my late father, a building contractor, challenging us with questions like ‘which of these bulldozers has more horsepower?’ or at a later stage ‘do you think cars will ever be able to drive on solar energy?’. He was also the person that awoke my interest in mathematical and physical puzzles, and solving ‘brain-teasers’ is something I still fancy very much.

At secondary school I developed an interest in mathematics and physics, and for my university study I was torn between studying physics in Amsterdam or technical physics at the University of Twente. A combination of the university campus at Twente, lots of sporting facilities and being at a relative distance from my parental home made me decide to choose the latter in 1975.

Although I could follow this study with reasonable ease, it still took me considerably longer than normal; those were the days of self-reflection and discovery, living in community-like student houses with, admittedly, a healthy amount of partying. Interestingly enough, my M.Sc. thesis work consisted of the study of sensitization of tin oxide (wet) solar cells using dye-containing Langmuir-Blodgett monolayers, a topic that has later gained a lot of attention by the excellent work of Michael Grätzel.¹ Apparently already at that stage the combination of solid-state/semiconductor physics and (organic) chemistry held my attention.

Education/Employment
M.Sc. Applied Physics, University of Twente
Ph.D. Technical Sciences, University of Twente
Scientist at CSEM, Chemical Sensors Department
Senior Scientist at IMT
Program Director μTAS at MESA, University of Twente
Part-time appointment as Full Professor ‘Microfluidics’
Program Director MiCS at MESA⁺, University of Twente
Simon Stevin Award, STW
2002 – the present: Full Professor at ‘BIOS’-chair, The Lab-on-a-Chip Group

Ph.D. work

After my masters thesis I was offered a Ph.D. position on the topic of chemically modified ISFETs (Ion Sensitive Field Effect Transistors) in 1983, in a joint project supervised by Piet Bergveld and David Reinhoudt. In these 4 years my scientific curiosity, and academic attitude was very much formed. Piet Bergveld, well-known for the discovery of the ISFET, taught me to have an independent mind and a problem-solving approach, whereas in the group of David Reinhoudt I became aware what ‘big science’ was about. Reinhoudt, nowadays one of the most prominent of Dutch chemists, very much stimulated me to ‘look around’ and read Science and Nature, for which I am still very grateful (I am even much more grateful for the fact that I met my wife Trudy in Reinhoudt’s lab, exactly 20 years ago). Working in two completely different groups (a Biosensors lab and a basically organic synthesis lab) was quite a challenge, but it offered several opportunities, as for instance combining the best of both worlds. I was lucky enough to do a lot of travelling: to Japan and the U.S. and started to develop a sense for the ‘global perspective’ of research.

The initial description of my Ph.D. work aimed at the realization of chemically modified ISFETs by monolayer chemical coating,² but it soon appeared that it would be practically impossible to eliminate the intrinsic pH-dependence of the surface in this way. Thus, it was decided to coat ISFETs with ion-selective polymers to create CHEMFETs, and special attention was paid to realise a reversible interface by the introduction of an intermediate hydrogel layer (which additionally appeared to reduce the CO₂ interference).³ My work was the start of a series of almost 10 Ph.D. students, and resulted in a commercial product now used in Dutch greenhouses for environmental control. A small, but quite interesting element of my work was to reveal the origin of anionic sites in PVC (a much used polymer for ion-sensitive electrodes that exhibits an intrinsic permselectivity), probably my nicest publication of that time.⁴

The Swiss years

After my Ph.D., I accepted a job at the Swiss center for microelectronics (CSEM) in Neuchâtel, where I became responsible for the development of chemical sensors. Apart from continuing the CHEMFET work, an amperometric microsensor for detection of active chlorine (hypochloric acid) in drinking water was successfully developed.⁵ This sensor, with a ppb detection limit, is now still used by one of the largest water distributors in France. A very important turning point was when I met Nico de Rooij, a world-famous MEMS researcher and a very fine person, who was MEMS professor at IMT at the University of Neuchâtel. Apart from numerous common adventures at conferences, to me, he is the person of the pragmatic approach. Like no one else I know, he has a very good nose for industrial applications. Together with a colleague and friend in these years, Bart van der Schoot, my first μTAS activities started. It was during this same period that I met a certain young, enthusiastic researcher in the elevator in the CSEM building, who had very ambitious plans: ‘I want to build a complete analytical lab on a chip’. That person, whom I knew from work on ion-selective microelectrodes was Andreas Manz.

After 4 years of seemingly endless ‘holiday time’ in Switzerland (cycling and hiking in the mountains, skating on frozen lakes and many, many ski-outings) my wife and I decided it was time for a great party, and we got married, resulting a year later in the birth of our daughter Line.

μTAS work at MESA

For a variety of personal reasons we decided in 1993 to return to the Netherlands, where I was offered a position to set up and coordinate a μTAS research program at MESA, University of Twente, at that time directed by Jan Fluitman. With a one year salary guarantee and 25 k$ for organizing a workshop, it meant writing lots, lots of proposals in order to get the program going. The workshop, organized first in 1994, happened to become the first of the successful μTAS series. The μTAS research orientation, though started slowly, resulted in about 30 researchers working now on this topic in MESA⁺. Although the years 1993–1997 were not very productive in terms of research output, I was lucky enough to engage Richard Schasfoort, with whom, in a creative moment, we were able to conceive and realize the FlowFET (Fig. 1), a device able to switch the electroosmotic flow (EOF) by electrically changing the zeta potential of the channel wall.⁶ This original work generated a lot of enthusiasm and momentum, and was a significant factor in my nomination as Full Professor in 1998. By then, my research interests had broadened: a strong focus on microfluidics based upon silicon technology,^7,8 besides work on analytical systems (e.g. a flow injection microsystem for ammonia detection⁹ and a chip-hydrodynamic chromatography (HDC) system¹⁰) and microreactors, both coordinated by Han Gardeniers.¹¹ While working with EOF-related microfluidics I became more and more interested in further scaling down the dimensions, and thus focusing at nanofluidics was a logical consequence. In the meantime the chair of Piet Bergveld had become available, and I was very happy the faculty gave me a chance to take over this chair in summer 2002 with Piet’s retirement.

Former μTAS group at summer school in Riederalp (CH).

Fig. 1 FlowFET structure (from ref. 6).

BIOS-chair: Bio-nanofluidics research

During my time at MESA (nowadays MESA⁺), I always maintained very good contacts with the MEMS group of Miko Elwenspök, and in particular his two ‘wizard’-technicians, Erwin Berenschot and Meint de Boer. With Niels Tas, as senior scientist, a lot of top-down nanofluidics work was realized (see Fig. 2), during which we discovered exciting science such as negative pressure and negative slip length, thus far unknown to us.^12–14 In 2002, I was awarded the Simon Stevin award from the Dutch Technical Science Foundation (STW), which meant 500 k$ ‘free-spending’ project money. The award was used for starting a nanofluidic program, later slightly reoriented by some Scandinavian influence towards Nanofluidic Single Cell Analysis (NanoSCAN).¹⁵ This program illustrates my most recent research interest: making micro/nanotechnology available to life-science and biomedical researchers and utilizing and investigating single (living) cells with these new tools. With all of the actual ‘buzz’ about nano and its potential threats (‘the Grey Goo’), a living cell, nature’s own and ultimate nanotechnology, with all its complex functions like recognition, multiplication, selective transportation, parallel operation and self repair, appears the perfect object AND inspiration for new research.¹⁶ As a first application example, the study of cell-apoptosis using nanotools as a function of local biochemical and electrical stimuli has our interest, but of course also simpler microfluidic systems for cell studies are being developed.

BIOS group at winter school in Riederalp (CH).

Fig. 2 Bubblepump structure (from ref. 12).

Research philosophy

Throughout my career, multidisciplinarity has been a central theme. Bringing together different communities and cultures has always been a challenge to me. It is amazing to see how little is known within one research area about well-established knowledge in another field. Conferences are one very effective means of breaking down these barriers, and I think last year’s Gordon conference on microfluidics, that I had the privilege to chair, was a nice example of this multidisciplinarity. In addition, it was held in a marvelous place, Big Sky resort in the Rockies, giving people a chance to combine the useful with the agreeable. The Gordon format, with free spendable afternoons that give you a chance for some outdoor activities, has stolen my heart and we have adapted it in our group in recent summer- and winterschool meetings in the Swiss Alps.

In the future my scientific motivation will continue to find its base in two tracks, ‘understanding phenomena’ and ‘application of micro/nanotechnology’, but with two new additional elements: using the (living) cell as a central theme, and biomedical as the application environment.

Conclusions

Looking over the past, I conclude that I was lucky that my research topic became very popular and the field expanded rapidly. With μTAS, MEMS technology was brought to analytical chemists. Research on microreactors currently does the same for chemical engineers, and the recent focus on cell-related research will make micro- and nanotools available to researchers in the life-science area. Thus, there is no such thing as a ‘killer-app’ for micro-and nanotechnology in these areas but rather an infiltration of new technologies in several research fields that open up new opportunities. With an optimistic view I believe that nanotechnology and nanotools will generate new knowledge that can be used to better control and utilize phenomena at the cellular level to improve our lives.

So far, my R&D career has been very exciting and inspiring, and with my actual research group, BIOS, with open-minded, creative and enthusiastic people, I look forward with full confidence to an even more adventurous and challenging future!

For more information about BIOS: http://mesainfo.el.utwente.nl/mutas/bios/index.php

Conferences
(Co)-chairman μTAS ‘94
Chairman μTAS 2000
Chairman GRC on Microfluidics 2003
Chairman Nanotech 2003
 
Journals/books
Section editor μTAS in S&A B
International Advisory Board of Lab on a Chip journal
(Co)-Editor Lab-on-a-Chip, Kluwer Academics, Dordrecht, The Netherlands, 2003.
 
Memberships
Scientific Committee of the European Conference on Micro and Nanotechnologies for Life Sciences (NanoTech).
Scientific Committee of the μTAS meetings.
Technical Programme Committee ‘ESSDERC 99’
Technical Programme Committee ‘Eurosensor XIII’ and ‘Eurosensors XIV’
Technical Programme Committee ‘MEMS 2000’, MEMS 2003
Scientific Committee of the International Conference on Microreaction Technology (IMRET)
Advisory Board of the International Micromachine Symposium series.
Advisory Board of the International Micromachine Meeting
Delegation Leader of Benelux for the International Micromachine Summit
Member of AAAS
Scientific Advisor Sentron CMT BV
NEXUS Academic Working Group

References

1. B. Oregan and M. Gratzel, A Low-cost, High-efficiency Solar-cell based on Dye-sensitized Colloidal TiO₂ Films, Nature, 1991, 353(6346), 737–740.
2. A. van den Berg, P. Bergveld, D. N. Reinhoudt and E. J. R. Sudhölter, Sensitivity Control of ISFETs by Chemical Surface Modification, Sens. Actuators, 1985, 8, 129.
3. E. J. R. Sudhölter, P. D. van der Wal, M. Skowronska-Ptasinska, A. van den Berg, P. Bergveld and D. N. Reinhoudt, Modification of ISFETs by Covalent Anchoring of Poly(hydroxyethyl methacrylate) Hydrogel – Introduction of a Thermodynamically Defined Semiconductor Sensing Membrane Interface, Anal. Chim. Acta, 1990, 230, 59.
4. A. van den Berg, P. D. van der Wal, M. Skowronska-Ptasinska, E. J. R. Sudhölter, D. N. Reinhoudt and P. Bergveld, Nature of Anionic Sites in Plasticized PVC Ion Selective Membranes, Anal. Chem., 1987, 59, 2827.
5. A. van den Berg, A. Grisel, E. Verney-Norberg, M. Koudelka-Hep, B. H. van der Schoot and N. F. de Rooij, An On-wafer Fabricated Free-Chlorine Sensor with ppb Detection Limit for Drinking Water Monitoring, Sens. Actuators, 1993, 13(1–3), 396–399.
6. Richard B. M. Schasfoort, Stefan Schlautmann, Jan Hendrikse and Albert van den Berg, Field-Effect flow control for microfabricated fluidic networks, Science, 1999, 286, 942–945.
7. A. van den Berg and T. S. J. Lammerink, Micro Total Analysis Systems: Microfluidic Aspects, Integration Concept and Applications, Topics Curr. Chem., 1997, 194, 21–50.
8. Y. Fintschenko and A. van den Berg, Silicon Microstructures and Technologies in Separation Science, J. Chromatogr., A, 1998, 819, 3–12.
9. R. M. Tiggelaar, T. T. Veenstra, R. G. P. Sanders, E. Berenschot, H. Gardeniers, M. Elwenspoek, A. Prak, R. Mateman, J. M. Wissink and A. Van den Berg, Analysis systems for the detection of ammonia based on micromachined components modular hybrid versus monolithic integrated approach, Sens. Actuators, B, 2003, 92(1–2), 25–36.
10. E. Chmela, M. T. Blom, J. G. E. Gardeniers, A. van den Berg and R. Tijssen, A pressure driven injection system for an ultra-flat chromatographic microchannel, Lab Chip, 2002, 2(4), 235–241.
11. M. Brivio, R. H. Fokkens, W. Verboom, D. N. Reinhoudt, N. R. Tas, M. Goedbloed and A. van den Berg, Integrated microfluidic system enabling (bio)chemical reactions with on-line MALDI-TOF mass spectrometry, Anal. Chem., 2002, 74(16), 3972–3976.
12. N. R. Tas, J. W. Berenschot, T. S. J. Lammerink, M. Elwenspoek and A. van den Berg, Nanofluidic bubble pump using surface tension directed gas injection, Anal. Chem., 2002, 74(9), 2224–2227.
13. N. R. Tas, J. W. Berenschot, P. Mela, H. V. Jansen, M. Elwenspoek and A. van den Berg, 2D-confined nanochannels fabricated by conventional micromachinin, Nano Lett., 2002, 2(9), 1031–1032.
14. N. R. Tas, P. Mela, T. Kramer, J. W. Berenschot and A. van den Berg, Capillarity induced negative pressure of water plugs in nanochannels, Nano Lett., 2003, 3(11), 1537–1540.
15. http://mesainfo.el.utwente.nl/mutas/bios/index.php.
16. H. Andersson and A. van den Berg, Microtechnologies and Nanotechnologies for Single Cell Analysis, Curr. Opin. Biotechnol., 2004, 15(1).

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