Optical detection in microfluidics: From the small to the large

Herein we discuss two broad approaches for performing high sensitivity optical detection within microfluidic environments. First, we describe recent work in which fluorescence lifetime imaging has been shown to be a sensitive probe of environmental parameters such as pH, viscosity, molecular concentration and temperature. Additionally, we demonstrate how dynamic fluorescence lifetime imaging can be used to probe mixing dynamics in segmented-flow microfluidic systems. Moreover, we describe recent work at Imperial College London in which semiconducting polymer light emitting diodes and polymer photodetectors are integrated with microfluidic systems to define a novel format for point-of-care diagnostics.