Microfluidic platforms for lab-on-a-chip applications

Abstract

We review microfluidic platforms that enable the miniaturization, integration, parallelization, and automation of biochemical assays. Nowadays, there is an unmanageable variety of alternative approaches that can do this in principle. Here, we focus on those kinds of platforms only that allow performance of a set of microfluidic functions-defined as microfluidic unit operations-that can be easily combined within a well-defined and consistent fabrication technology to implement application-specific biochemical assays in an easy, flexible, and ideally monolithic way. The microfluidic platforms discussed in the following sections are capillary test strips, also known as lateral flow assays, the 'microfluidic large-scale integration' approach, centrifugal microfluidics, the electrokinetic platform, pressure-driven droplet-based microfluidics, electrowetting-based microfluidics, SAW driven microfluidics, and, last but not the least, 'free scalable non-contact dispensing'. The microfluidic unit operations discussed within these platforms are fluid transport, metering, mixing, switching, incubation, separation, droplet formation, droplet splitting, nL and pL dispensing, and detection.