ABSTRACT
The fluid flow in microfluidics is based on the classical theories of fluid dynamics: low-Reynolds number flows. Some common fluids that are used in microfluidics include protein or antibody solutions, buffer solutions, bacterial or cell suspensions, and blood samples. The movement of a fluid through a microfluidic system is facilitated by capillary forces. A fluid flows when the adhesive molecular forces are stronger than the cohesive intermolecular forces present in the fluid. In the early days, the fabrication of microfluidic devices mainly relied on techniques transferred from the conventional two-dimensional integrated circuit (IC) and silicon-based two- or threedimensional MEMS processes. This includes photolithography, thin film metallization, and chemical etching. Later, glass-based, glass silicon, glass-polymer mixed microfluidic fabrication techniques and devices started to garner more interest. Most common materials that are used for microfluidic chip manufacturing are low fluorescence Schott Borofloat glass, Corning borosilicate glass, fused silica, quartz silicon, PMMA, SU-8, PDMS, steel, aluminum, and copper.
