How can mankind take advantage of electricity? What can you do with a transistor? What is a PC supposed to do on the internet? Most of the pioneers of the modern information age have been ridiculed by these questions in the early stages of their discoveries. And also many of these fine people have undountedly underestimated the impact of their research much like it is hard for parents to predict the future achievements of their children from their elementary school education. They just know that on the basis of a decent education, "something good" will happen.

While the potential of microelectronics and information technology is now widely acknowledged, there is still a lot to explore in its neighborhood. How about integrating mere information processing with the acquisition of information from the real world. In a traditional laboratory, for instance, ,information is usually obtained from a measurement setup which interfaces over an electronic bus system with a computer. Can we integrate physical data acquisition and processing?

Microtechnology has demonstrated that incorporating physical, chemical and optical sensing capability with microelectronics is indeed feasible. On the analogy, molecular biology is now on the verge of turning presently often empirically guided medicine into an information science. Even though this development is still in its infancy, experts forecast that this step will revolutionize medicine and biology from a predominantly emperical sciences more towards the "exact" sciences like physics.

For this to happen, the gap between the nanoworld of complex biomolecules and cells as well as our manipulation and sensing tools has to be bridged. One way is direct interaction, for example with modern tools like atomic force microscope tips. However, this mechanical approach is cumbersome in practice and does not comply with the natural mode of interaction. Almost all biomolecules in a living organism are within or at least in contact with some kind of a liquid matrix - mostly water - by which they are transported and herethey encounter there reaction partners.

Microfluidic devices in a certain sense mimic this natural environment. Engineering allows to equip these artificial systems with functionality to manipulate and detect biomolecules and cells in their natural environment. Over the last decade microfluidics has unquestionally evolved to one of the key enabling technologies in the life sciences.

Microfluidics is the science of hydrodynamics confined to typically multi-scale environments with (some) characteristic dimensions on the micron-scale.