Critical aspects in microfluidic systems design

Classical microfluidic systems can be constructed in three major formats: microarray, droplet and continuous-flow systems. The format of construction is dictated by the intended practical application and therefore is dependent on the compatibility between the non-biological and biological components of the microfluidic system. Understanding the physical aspects of microfluid dynamics is critical because in droplet-based and continuous-flow microfluidic systems, fluid surrounds and interacts with encapsulated respectively or nonencapsulated molecules. This review highlights the key requirements in the design and construction of droplet-based and continuous-flow microfluidic systems, and provides an overview of the respective roles played by the surface of the microfluidic device, its channel geometry, and the properties of the microfluids.