Application of multi-dimensional fluorescence imaging to microfluidic devices

The field of microfluidics has developed rapidly with promising applications such as ´lab on a chip´ devices for micro-assays and efficient chemical reactions and processes, including e.g. DNA sequencing. The design of microfluidic devices requires an understanding of fluid flow and dynamics, which we demonstrate can be enhanced by direct observation using (time-resolved) multi-dimensional fluorescence imaging (MDFI). As well as providing opportunities to study fluid dynamics, MDFI provides new opportunities for read-out and analysis which may be applied to assay development and to studies of reaction kinetics e.g. stop-flow experiments. We present our first results using time-gated fluorescence imaging, resolved with respect to 2 or 3 spatial dimensions. Time-resolved imaging of fluorescence polarisation anisotropy may be used to image mixing in a microfluidic device via maps of the rotational correlation time, which is proportional to the local fluorophore solvent viscosity