Surface-tension-confined microfluidics and their applications.

This article is a brief overview of the emerging microfluidic systems called surface-tension-confined microfluidic (STCM) devices. STCM devices utilize surface energy that can control the movement of fluid droplets. Unlike conventional poly(dimethylsiloxane)-based microfluidics which confine the movement of fluids by three-dimensional (3D) microchannels, STCM systems provide two-dimensional (2D) platforms for microfluidics. A variety of STCM devices have been prepared by various micro-/nanofabrication strategies. Advantages of STCM devices over conventional microfluidics are significant reduction of energy consumption during device operation, facile introduction of fluids onto 2D microchannels without the use of a micropump, increased flow rate in a special type of STCM device, among others. Thus, STCM devices can be excellent alternatives for certain areas in microfluidics. In this Minireview, fabrication methods, operating modes, and applications of STCM devices are introduced.