Microfluidics is a branch of physics and biotechnology that studies the behavior of fluids at the microscale and mesoscale, that is, fluids at volumes thousands of times smaller than a common droplet. It also concerns the design of systems in which such small volumes of fluids will be used.
The behavior of fluids at the microscale can differ from 'macrofluidic' behavior in that factors such as surface tension, energy dissipation, and electrokinetics start to dominate the system. Microfluidics studies how these behaviors change, and how they can be worked around, or exploited for new uses.
It is a new science, having emerged only in the 1990s, so the number of applications for this technology is currently small. However, it is potentially significant in a wide range of technologies. Microfluidics is used in the development of gene chip technology, as well as in micro-thermal and micro-propulsion technologies.