We know about pumps which lifts water from well to the overhead tanks, but can we imagine a molecular size pump which can do a specialized job? These types of pumps, sensors, boats etc at micro and nano size can lead to a new kind of machines called MEMS which can be used to capture foreign particles or delivery of drugs to specific locations. Integration with biological systems they result in BioMEMS which can provide interface between micro and nano worlds and between biological and electromechanical worlds.