Shear-Driven Micro- and Nanofluidics

During the last decade, miniaturization has been a major issue in analytical and bio-analytical chemistry. Microsystems have generated a considerable activity at economic and scientific levels, and their importance in our everyday life is expected to increase considerably over the next few years. The drive towardminiaturization follows from an ever-increasing demand (from such fields as organic (polymer) synthesis, medical diagnostics and therapeutics, genomics, etc.) for analytical tools capable of identifying and quantifying all compounds within small sample volumes. Furthermore, methods should generate more precise results, higher sensitivity, and this in the fastest possible way. An efficient handling of minimal sample consumption can become possible by miniaturizing the analysis systems. Miniaturized fluidic systems can have several applications, such as amplification, digestion, and analysis of deoxyribonucleic acid (DNA) sequences or the separation and analysis of single defective cells in order to diagnose specific diseases at early stages. With the completion of the Human Genome Project, the analysis of gene and protein functions creates a huge demand for advanced biotechnological systems. These systems can only be realized using miniaturized fluid handling systems, which allow the rapid and efficient analysis of structures and functions with minimal sample volume. Due to this increasing demand, microfluidics has rapidly turned into an interdisciplinary research field equally including physics, chemistry, materials science, and engineering. The generation of a stable and controllable fluid flow in microfluidic devices is a major issue, and a lot of research work has been put into optimizing the flow driving methods. Not only conventional methods (derived from macroscopic applications) like pressure-driven and electroosmotic flows have been scaled down, but also novel methods like shear-driven flows (SDF) have been introduced.