BioMEMS (Biological Micro-Electro-Mechanical Systems) technology, especially for biosensors, plays a critical role in the process of information gathering with the technologically advanced development of our civilization. ?Surface stress- based biosensors? are a relatively new class of biosensors, which make use of the free energy change, the underlying concept in any binding reaction, and hence offer a universal platform for biological or chemical sensing. In the book, a new surface stress-based polydimethylsiloxane (PDMS) micro membrane biosensor is proposed, designed, fabricated and tested. Each sensor consists of two micro membranes, one acts as active membrane and the other as reference. This design has sensitive surface stress measurements associated with specific analytes interactions on the active membrane''s surface.