10th Anniversary Issue: France

Historically, France was not one of the pioneering countries in microfluidics. Some rather early papers,^1,2 using crude “hand-fabricated” microflow systems, can a posteriori be considered as early steps into the field, but it seems fair to rather date the significant entry of the French scientific community to the start of this millennium. Since then, French microfluidics has risen to an excellent standard in academic terms, to be on par with the major European countries in the field with respect to total number of publications/communications. This rather rapid development was strongly rooted in some specific strengths of French science, which in turn gives “French microfluidics” (if such a generalization can have any meaning, in a field so intrinsically diverse) a specific colour.

First, a number of contributions from French groups are rather fundamental in nature, and rooted in a strong tradition in theoretical physics, solid state physics and soft matter. Notably, the “spirit” of the Nobel Prize winner Pierre Gilles de Gennes, who promoted the application of fundamental thinking to practical problems, e.g., semi-quantitative “scaling laws” approaches, still fertilize the field and a number of his “intellectual heirs” contributed to the emergence of microfluidics in France. A good example is probably the now very popular family of devices for flow management in microchannels based on asymetric structures,³ which directly took its inspiration from a series of works by Prost and Ajdari in the mid-nineties, themselves exploring the consequences of the Curie principles on the fluctuation-dissipation equation.^4,5 Some articles, such as those by Mignard (DOI: 10.1039/c0lc00058b), Baroud (DOI: 10.1039/c0lc00104j) and Tabeling (DOI: 10.1039/c0lc00192a), in this issue are examples of this rooting of French microfluidics in fundamental physics. This "physically-inspired" innovation also penetrates progressively the analytical chemistry community, as exemplified e.g. in DOI: 10.1039/c0lc00510j

A second specific nature of French microfluidics is its close connection with “biology inspired physics”, also a strong field in France. This has led to a series of developments, such as the work presented in this issue by the group of Ladoux (DOI: 10.1039/c0lc00221f) and earlier papers by this group and others.^6,7 This line of research is somewhat at the “frontier” of microfluidics, but I believe that they offer a vast field of exploration and will certainly in the near future lead to a very fruitful convergence.

Third, in the last ten years, strong efforts were dedicated by French institutions to develop infrastructures in micro and nanotechnologies. Although these efforts were initially focused mainly on “hard” micro-nanoelectronics or MEMS, as in other countries they also served as nucleation points for microfluidic groups with the potential to develop very complex and/or nanoscale devices. This is exemplified by the paper by Haghiri-Gosnet et al. (DOI: 10.1039/c0lc00079e) in this issue, or a series of developments in digital microfluidics by the Grenoble LETI⁸ group. Besides this inspiration from microelectronics, a strong demand has also been emerging in the last year for fast, low-cost and high throughput “soft” or “plastic” technologies for chip production. Indeed several companies (e.g., Microfluidic Chip Shop, Dolomite, Ikerlan, and others) have been developing in Europe, but to our knowledge there is in France no dedicated “microfludic foundry”. This lack has stimulated the recent launch in Paris of the “Pierre Gilles de Gennes Institute for Microfluidics” (opening expected in 2013), which will gather microfluidics groups and a company incubator around a microfabrication facility entirely designed for microfluidic technologies.

Finally, one may acknowledge that the translation of these different research strengths into practical and industrial applications is somewhat lagging in France. Rhodia, a major French company in chemistry, has created in Bordeaux a large joint laboratory with CNRS entirely dedicated to microfluidics applications (see e.g. the paper by Mignard (DOI: 10.1039/c0lc00058b) in this issue), but besides this remarkable initiative, the involvement of the French industry in microfluidics is limited. A probable reason is a general weakness of the instrumentation industry in the country. In spite of interesting governmental incentives for the creation of startups, to our knowledge only a few have achieved international recognition. For instance, a recent survey of microfluidic companies in “FluidicMEMS” ⁹identified only two French-based ones (against e.g. 14 in Germany, 4 in the UK or Netherlands): Fluigent¹⁰, based in Paris, is now well recognized for its microfluidic flow controllers and developing diagnosis applications; Cytoo,¹¹ in Grenoble, is developing microwell plates for cell assays, a technology not microfluidic per se, but related to the new “frontier” of microfluidics in cell biophysics discussed above. It is worth mentioning also Kloe,¹² a provider of direct-write microfabrication tools, now also developing integrated microfluidic-optic components. The major French diagnosis companies, such as Bio-Merieux, are also involved, but they remain small as compared to international “giants” such as General Electric, Johnson & Johnson, Roche, Abbott and others. Thus, regarding industrialization French microfluidics groups definitely have to think at the European level.

References

1. L. Mitnik, C. Heller, J. Prost and J. L. Viovy, Science, 1995, 267, 219–222.
2. P. Mayer, J. Bibette and J. L. Viovy, Mater. Res. Symp. Proc., 1997, 463, 57–67.
3. A. D. Stroock, S. K. W. Dertinger, A. Ajdari, I. MezicI, H. A. Stone and G. M. Whitesides, Science, 2002, 295, 647–651.
4. A. Ajdari, J. Prost and C. R. Acad, Sci. Ser II, Paris, 1992, 315, 1635–1639.
5. J. Rousselet, L. Salomé, A. Ajdari and J. Prost, Nature, 1994, 370, 446–448.
6. M. Thery, V. Racine, M. Piel, A. Pepin, A. Dimitrov, Y. Chen, J. B. Sibarita and M. Bornens, Proc. Natl. Acad. Sci. U. S. A., 2006, 103, 19771–19776.
7. M. Poujade, E. Grasland-Mongrain, A. Hertzog, J. Jouanneau, P. Chavrier, B. Ladoux, A. Buguin and P. Silberzan, Proc. Natl. Acad. Sci. U. S. A., 2007, 104, 15988–15993.
8. R. Bavière, J. Boutet and Y. Fouillet, Microfluid. Nanofluid., 2008, 4, 287–294.
9. http://fluidicmems.com/list-of-microfluidics-lab-on-a-chip-and-biomems-companies/ .
10. http://www.fluigent.com/ .
11. http://www.cytoo.com/ .
12. http://www.kloe.fr/ .

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