Microfluidics is a science and technology of manipulating and controlling fluids, usually in the range of microliters (10-6) to picoliters (10-12), in networks of channels with lowest dimensions from tens to hundreds of micrometers. This emerging discipline takes its origin in the early 1990s and has grown dramatically since then, due to the increasing popularity of microscale analytical chemistry technique and the development of microelectronic technologies. It is a multidisciplinary field intersecting engineering, physics, chemistry, biochemistry, nanotechnology, and biotechnology. Microfluidics is a very attractive technology for both academic researchers and industrials since it considerably decrease the sample and reagent consumption, shortens the time of experiments, and thereby, reduces the overall cost of applications. Thanks to the volume required, microfluidics represents a promising alternative to conventional laboratory techniques as it allows achieving complete laboratory protocols on a single chip of few square centimeters. Basic idea of the microfluidic biochips is to integrate the sample preparation, pretreatment, and detection on one chip. Microfluidic systems have widespread applications in medical industry including blood cell separation, pathogen/toxin detection, biochemical assays, chemical synthesis, genetic analysis, drug screening, electro-chromatography, organ-on-chip, and many others. Microfluidic biochips can be fabricated using silicon, glass or polymeric (i.e. PDMS, PMMA) substrates using micromachining techniques.