Abstract
Recently, functional droplet-based microfluidic systems have played an important role in chemistry, biology, biomedicine, and industry applications due to their capabilities on uniform dosage control, multifunctional sample assay, reaction time reduction, and high throughput operation. The formation of micro droplets in gaseous or liquid environments can be achieved by either droplet ejection in atmosphere/vacuum, emulsification in microchannels, or electrokinetic forces on solid surfaces. This paper reviews some of the recently developed micro droplet generation techniques on the aspects of droplets generation principles, manipulation methods, technical capabilities, and potential applications. Advances in the capacity, efficiency, and stability of micro droplet generators provide the opportunity to realize lab on a chip (LOC) or digital micro fluidic (DMF) systems for versatile practical applications.