**Abstract**

Microfluidic devices are based upon the behavior of fluids at the microenvironment level. They offer innumerable applications in the field of science and technology. Their scope is not limited to single field and now have applications in various fields such as biomedical, energy, chemicals and environment as well. Their major advantages are low experiment to cost ratio, and fast response time. Surface wettability is one of the factors contributing to the working of microfluidic devices. Surface wettability measurement is a very critical technique to measure the flow of micro fluids in microfluidic applications. In microfluidic devices the detection of small volume change with change in fluid properties is very minor because of the micrometer range. In order to detect this small change in micrometer range, an *in situ* wetting measurement is required. In this chapter, we have discussed about types of taxis, microfluidic devices: an application of taxis, microfluidic applications and role of surface wettability in microfluidic devices.

**Keywords:** microfluidic, devices, surface wettability, lab-on-chip, applications, biomedical
